Colorado Potato Beetle - Salisbury Greenhouse AB Colorado Potato Beetle By Rob Sproule The Colorado potato beetle (Leptinotarsa decemlineata), alias potato bug, alias 10-striped speaman, is the most destructive potato crop pest in Canada. After entering Canada via Ontario in 1870, it has become a ravenous and economically destructive pest across the Maritimes, hitting New Brunswick and P.E.I. especially hard. It’s a nuisance across the Prairies, though not as pervasive. Unlike many garden pests, which originated in the Eastern Hemisphere and invaded across the oceans, Colorado potato beetles came from…wait for it…Colorado. From there, it has spread almost worldwide and has shown a remarkable ability to become immune to even the harshest insecticides (it even developed a defence against DDT in 1950s). Identification You’ll know one when you see one. About 1 cm long, adults sport five bold, brown stripes down the length of their golden back. If they weren’t so destructive, we’d say they were downright beautiful. The larvae are striking, with a dark red body, black head and jaws big enough to rip your potato leaves to smithereens.

Life Cycle Potato beetle adults overwinter in the soil around their victimized potato plants. In spring, they emerge to seek host plants, feed for a few days, and lay up to 500 yellow or orange eggs in early July. Although they can produce multiple generations per year in warmer countries, in Canada, the prohibitive climate typically limits them to one generation; being cold has its advantages. Damage These beetles are ravenous and can strip potato fields bare with alarming speed. The larvae can chomp up to 40 cm2 of foliage per day, per critter. Multiply that by each female laying up to 800 eggs, and the math proves terrifying. Adults clock in at 10 cm2 of foliage per day. Plants without leaves can neither photosynthesize nor produce big spuds. Eventually, weakened plants will simply die from stress. Control Make sure to rotate your potato crop every year so that the emerging beetles have a tougher time finding hosts in spring. Laying down an organic mulch, such as straw, can confuse emerging larvae enough to keep them wandering until starvation. Potato beetles have a host of predators, and some of them have even been harnessed for commercial use.

From ground beetles, parasitic wasps and nematodes to a pathogenic fungus, sometimes your garden army will mobilize itself to keep invaders under control. Curbing your chemical use in all areas, and fostering a healthy ecosystem, will go a long way to supporting the predators. Colorado potato beetles are famous for their ability to withstand and evolve against insecticides, so applying chemicals will do more harm than good. After all, this is an insect that lives exclusively on leaves from the Nightshade family, which is toxic to almost everything else. A World Player Not many bugs have been accused of being covert Cold War agents. Potato beetle history reads like a spy novel. In the early 1950s, the Warsaw Pact accused the CIA of air-dropping potato beetles across East Germany to destroy their crops. After fields that American planes flew over were suddenly afflicted, a propaganda campaign, complete with posters, sprang up. Children across East Germany were sent out after school to collect and destroy the beetles, which were labelled amikafer, or “Yankee beetle.” The allegation was never proven one way or the other. In the 2014 Ukrainian conflict, pro-Russian rebels sported colours of St.

George to show their allegiance to Moscow. The black and gold armbands have earned them the derogatory nickname kolorady, meaning “Colorado beetle” in both Ukrainian and Russian. – Keep in Touch with what’s happening at Salisbury Greenhouse Related Posts: Colorado potato beetle - 必应 Sign in Colorado potato beetle The Colorado potato beetle (Leptinotarsa decemlineata), also known as the Colorado beetle, the ten-striped spearman, the ten-lined potato beetle or the potato bug, is a major pest of potato crops. It is approximately 10 millimetres (0.39 in) long, with a bright yellow/orange body and five bold brown stripes along the length of each of its elytra. It can easily be confused with its close cousin and look-alike, the false potato beetle. Colorado potato beetle History The beetle was discovered in 1824 by Thomas Say from specimens collected in the Rocky Mountains on buffalo-bur, Solanum rostratum. The origin of the beetle is somewhat unclear, but it seems that Colorado and Mexico are a part of its native distribution in southwestern North America.

In about 1840, the species adopted the cultivated potato into its host range and it rapidly became a most destructive pest of potato crops. The large scale use of insecticides in agricultural crops effectively controlled the pest until it became resistant to DDT in the 1950s. Other pesticides have since been used but the insect has, over time, developed resistance to them all. Colorado potato beetle Life cycle Colorado potato beetle females are very prolific; they can lay as many as 800 eggs. The eggs are yellow to orange, and are about 1 mm long. They are usually deposited in batches of about 30 on the underside of host leaves. Development of all life stages depends on temperature. After 4–15 days, the eggs hatch into reddish-brown larvae with humped backs and two rows of dark brown spots on either side. They feed on the leaves. Larvae progress through four distinct growth stages (instars). First instars are about 1.5 mm long; the fourth is about 8 millimetres (0.31 in) long. The larvae in the accompanying picture are third instars.

The first through third instars each last about 2–3 days; the fourth, 4–7 days. Upon reaching full size, each fourth instar spends an additional several days as a non-feeding prepupa, which can be recognized by its inactivity and lighter coloration. The prepupae drop to the soil and burrow to a depth of several inches, then pupate. Depending on temperature, light-regime and host quality, the adults may emerge in a few weeks to continue the life cycle, or enter diapause and delay emergence until spring. They then return to their host plant to mate and feed. In some locations, three or more generations may occur each growing season. Colorado potato beetle As a crop pest Colorado beetles are a serious pest of potatoes. They may also cause significant damage to tomatoes and eggplants. Both adults and larvae feed on foliage and may skeletonize the crop. Insecticides are currently the main method of beetle control on commercial farms. However, many chemicals are often unsuccessful when used against this pest because of the beetle's ability to rapidly develop insecticide resistance. The Colorado potato beetle has developed resistance to all major insecticide classes, although not every population is resistant to every chemical.

In the United Kingdom, where the Colorado beetle is a rare visitor on imported farm produce, it is a notifiable pest: any found must be reported to DEFRA. High fecundity usually allows Colorado potato beetle populations to withstand natural enemy pressure. Still, in the absence of insecticides natural enemies can sometimes reach densities capable of reducing Colorado potato beetle numbers below economically damaging levels. A ground beetle, Lebia grandis is a predator of the eggs and larvae and its larvae are parasitoids of the Colorado beetle's pupae. Beauveria bassiana (Hyphomycetes) is a pathogenic fungus that infects a wide range of insect species, including the Colorado potato beetle. It is probably the most widely used natural enemy of the Colorado potato beetle, with readily available commercial formulations that can be applied using a regular pesticide sprayer. Colorado potato beetle In Europe Further information: War against the potato beetle In 1877, the Colorado beetle reached Germany where it was eradicated. During or immediately following WWI, it became established near USA military bases in Bordeaux and proceeded to spread by the beginning of WWII to Belgium, the Netherlands and Spain.

The population increased dramatically during and immediately following WWII and spread eastward, and the beetle is now found over much of the continent. After World War II, in the Soviet occupation zone of Germany, almost half of all potato fields were infested by the beetle by 1950. The GDR government made the claim that the beetles were dropped by American planes. In East Germany they were known as Amikäfer (Yankee beetles). In the EU it remains a regulated (quarantine) pest for the UK, Republic of Ireland, Balearic Islands, Cyprus, Malta and southern parts of Sweden and Finland. It is not endemic in any of these Member States, although occasional infestations occur, as in Finland in the summer of 2011, when strong winds blew from Russia, where the species is endemic.

Colorado potato beetle In popular culture The beetle is documented in the documentary The Botany of Desire.[citation needed] In David Javerbaum's 2011 book The Last Testament: A Memoir by God, the eponymous deity states that on the sixth day he tried to create the perfect beetle over 400,000 times (all failures) until he settled upon the Colorado potato beetle. Commonly called a "tater bug", the striped thorax reminded old time musicians of the Italian style bowl-back mandolin, which are sometimes called "tater bug" mandolins. In Czechoslovakia, a children's book called "O zlém brouku Bramborouku" ("On the evil potato-eating beetle") by Ondrej Sekora was published in 1950. It presents the Colorado beetle as an enemy for communist agriculture from the West and instructs children to fight the beetle. ^ "Leptinotarsa decemlineata". Integrated Taxonomic Information System. ^ University of Florida (2007). "Featured creatures: Leptinotarsa spp.". Retrieved 11 August 2008.

^ J D Hare (Jan 1990). "Ecology and Management of the Colorado Potato Beetle, Annual Review of Entomology". Annual Reviews 35: 81–100. doi:10.1146/annurev.en.35.010190.000501 ^ Alyokhin, A., M. Baker, D. Mota-Sanchez, G. Dively, E. Grafius. (2008). "Colorado potato beetle resistance to insecticides". American Journal of Potato Research 85 (6): 395–413. doi:10.1007/s12230-008-9052-0 ^ Koloradonkuoriainen hyppyyttää tarkastajia perunapelloilla YLE news (Finnish) ^ Herrmann, Bernd (2009). "Schauplätze und Themen der Umweltgeschichte: Umwelthistorische Miszellen aus dem Graduiertenkolleg".

ISBN9783941875234. ^ James L. Skaptason. "Skaps' bug stamps". Retrieved 1 May 2006. ^ Memorabilia ^ Stamp ‹ Colorado beetle (Leptinotarsa decemlineata). colnect.com ^ David Javerbaum (2011) The Last Testament: A Memoir by God. Simon & Schuster. ISBN 1451640188 ^ a b c Sindelar, Daisy. "What's Orange and Black and Bugging Ukraine?". Radio Free Europe / Radio Liberty. Retrieved 18 May 2014.

Ukraine’s Reins Weaken as Chaos Spreads, The New York Times (4 May 2014) (Ukrainian) Lyashko in Lviv poured green, Ukrayinska Pravda (18 June 2014) ^ A guide to Ukrainian and Russian flags, The Economist (7 May 2014) Colorado Potato Beetle Colorado Potato Beetle Main_Content The Colorado potato beetle, Leptinotarsa decemlineata, is the most destructive pest of potatoes, eggplant, and tomatoes in the Mid-Atlantic region. This species has developed resistance to every known class of insecticides. A three-year study in fresh market tomatoes found that mass releases of Podisus maculiventris, a native predacious sting bug, and Edovum puttleri, an exotic egg parasite, reduced numbers of this invading pest. The stink bug was more effective and new studies will evaluate mass releases of this species combined with potato trap crops in order to protect the tomato crop.

Edovum puttleri emerging from crop pests and diseases – Page 4 – The Plantwise Blog Charlotte Elston 1 Comment Trinidad and Tobago Country Coordinator Shamela Rambadan sent the photo below of a Soursop (Annona muricata) plant brought into a clinic in County Victoria in Trinidad and Tobago by farmer Ramesh Ramnanan last month. The symptoms described included yellowed, distorted leaves and visible insects on the leaves, as seen in the photo. Plant health officer Zobida Mohammed diagnosed the symptoms to be caused by mealybugs and scale insects and recommended that the farmer used a suitable insecticide on the crop to avoid further damage. A photo of the leaves of a Soursop plant from a plant clinic in County Victoria. The insect pests are visible as white dots along the leaf veins. Image courtesy of Zobida Mohammed Charlotte Elston 2 Comments Roasted Arabica coffee beans.

Arabica coffee is highly prized as having the best flavour and quality of all coffee varieties, but the future of Arabica coffee is threatened by the impacts of climate change © Sage Ross, via Wikimedia Commons (License CC-BY-SA 3.0, 2.5, 2.0, 1.0) Coffee (Coffea) is the one of the world’s favourite drinks and the second most traded commodity after oil, accounting for annual retail value of US$ 90 billion. The two main species used in the production of coffee are Arabica coffee (Coffea arabica), which accounts for 70% of coffee production, and Robusta coffee (Coffea canephora). The productivity of Arabica and the distribution of many coffee pests and diseases are strongly linked to climate and seasonality. A series of recent studies have forecast the predicted effects of climate change on both the present and future distribution of Arabica coffee and the effects of climate change on the distribution and lifecycle of the world’s worst coffee pest, the Coffee Berry Borer (Hypothenemus hampei).

Charlotte Elston 6 Comments Coffee is one of our most popular drinks, but coffee production worldwide is threatened by the Coffee Berry Borer, a tiny beetle which affects the yield and quality of coffee beans © Frank Gruber, via Flickr (License CC-BY-NC-ND 2.0) The Coffee Berry Borer, Hypothenemus hampei, is a tiny beetle which is widely considered to be the most damaging pest of coffee plantations in the world. Originating in Africa, it is now found in almost all coffee growing areas in the world as an invasive species, with nearly 160 records from different areas worldwide on the Plantwise Distribution Map . Coffee is an extremely important commodity in many countries, including Brazil, Peru, Columbia, Vietnam, India and Indonesia. CABI is currently running a project led by Soetikno S. Sastroutomo in partnership with the Indonesian Coffee and Cacao Research Institute (ICCRI) and Papua New Guinea Coffee Industry Corporation Ltd (CIC) to address problems with the Coffee Berry Borer in Indonesia, where over 920,000 ha of coffee are infested, 95% of which are farmed by small holder farmers.

Papua New Guinea is one of the last two remaining coffee nations without the pest, so the project also aims to prevent the establishment of the pest in Papua New Guinea and save the country’s extensive coffee growing areas. The CABI project is applying knowledge from Coffee Berry Borer management in African and Latin American countries to create a country-specific management program with an emphasis on Integrated Pest Management techniques and training for farmers in order to combat the Coffee Berry Borer. A recent paper published this year highlights the potential for Integrated Pest Management (IPM) programs in the management of Coffee Berry Borer, using a case study from a large coffee plantation in Colombia. Farm managers and harvest workers received training workshops on pest management strategies based on prior research and the recommendations of the National Coffee Research Center in Columbia in order to implement effective IPM strategies. Continue reading → Charlotte Elston 3 Comments An adult Colorado Potato Beetle (License CC-BY-NC 2.0.

via Flickr) Eggplant or aubergine (Solanum melongena) is a crop often attacked by the Colorado Potato Beetle (Leptinotarsa decemlineata), a major insect pest of plants from the Solanaceae family including potato, tomato and eggplant throughout North America, Europe and Asia. This insect pest is exceptionally destructive to crops and readily develops resistance to a wide variety of chemical insecticides, making research into alternative control methods vital. Now new research has revealed that the use of clover cover crops in agricultural fields of eggplants may provide an economically and ecologically viable method of Colorado Potato Beetle management that is as effective as chemical insecticides in regulating the beetle populations. Charlotte Elston 2 Comments An Adult Soybean Aphid © Ho Jung Yoo, Purdue University (via Wikimedia Commons) Following on from a previous blog on the interactions between soybean plants and soybean pests, new research on soybean (Glycine max) responses to the soybean aphid (Aphis glycines) published in Molecular Plant-Microbe Interactions has revealed some of the complex and fascinating interactions between pests and their plant hosts.

This recent research led by Dr Gustavo Macintosh and Matthew Studham from Iowa State University has shown that soybean aphids can suppress the natural plant defense response of soybean plants to the aphids through the activation of what is known as an antagonistic decoy response. For example, the aphid will induce a plant defense that is not particularly effective against the pest (the ‘decoy’ defense) while suppressing the effective defense in order for it to continue feeding on the plant. It has further been found that aphids can actively suppress the effective defence responses of the plant while at the same time ‘hijacking’ the plant metabolism to improve the nutritional value of the plant for their own benefit. Soybean aphids do this by inducing asparagine synthase transcripts which improve the nutritional content of the phloem sap from which they feed.

Continue reading → Charlotte Elston Leave a comment Scanning electron micrograph of a soybean cyst nematode and egg © Ethan Hein via Flickr (License CC-BY-NC-SA 2.0) Soybean (Glycine max) is an important crop that provides a sustainable source of protein and oil worldwide in countries such as the USA, Brazil, Argentina, India and many African countries, including Nigeria, South Africa and Uganda. The soybean cyst nematode Heterodera glycines is a microscopic roundworm that feeds on the roots of soybean and is a major constraint to soybean production. This nematode causes more than US$1 billion in yield losses annually in the United States alone, making it the most economically important pathogen on soybean. For over 50 years the planting of resistant cultivars and crop rotation have been the main management strategy for this pathogen, and only a few resistant plant types are used due to undesirable traits in other resistant varieties of soybean. Moreover, the increase in virulent populations of the nematode on most known resistant plant sources coupled with the very limited knowledge of soybean resistance mechanism makes the development of new approaches for control of soybean cyst nematode a necessity.

Continue reading → Charlotte Elston 2 Comments Chocolate, a popular product of Cocoa © Andre Karwath (Wikimedia Commons, CC BY-SA 2.5 license) Cocoa, Theobroma cacao L. is the third most important export product in Ecuador; a country which produces 70% of the world’s highly prized Arriba cocoa. However, the sustainability of this crop is threatened by a number of devastating pest species including fungal diseases and insect pests. Among the most severe are the closely related fungal diseases Witches’ Broom Disease Moniliophthora perniciosa and Frosty Pod Rot Moniliophthora roreri, both of which occur in Ecuador. Frosty Pod Rot is an invasive disease which was originally identified in Ecuador in 1917 and has since spread rapidly to other Latin American countries. The fungal pathogen that causes Witches’ Broom Disease is a close relative of Frosty Pod Rot in the same Moniliophthora genus. In addition to the Moniliophthora diseases, Phytophthora spp.

can lead to Black Rot of cocoa.These fungal diseases are a principle constraint on world cocoa production and affect the pods, flowers, leaves and stems, causing a decline in production and reduction in bean quality with infested plantations suffering dramatic yield losses and in some cases total loss of production. Breeding for disease resistance in cocoa is a key factor in maintaining sustainability of cocoa, since there is widespread concern over fungicide resistance, the safety and effectiveness of widespread pesticide use and recent tightening of regulations regarding pesticide residues on cocoa. The INIAP , national research institute of Ecuador, in collaboration with Mars Chocolate and the USDA is investing in substantial cocoa breeding programs with the aim of developing more productive, disease resistant, high yielding cocoa plants for Ecuadorian cocoa farmers. Continue reading → Pests | Vegetable Crop Entomology Vegetable Crop Entomology Search for: Pests Below is an overview of many of the common arthropod pests encountered by Wisconsin vegetable producers. Aphids Aphids are small (1/10–1/5 inch) insects with two tailpipe projections (called cornicles) placed posteriorly on each side of the abdomen. Both winged and non-winged forms can be found on plants.

Feeding damage from large numbers of aphids can cause plants to wilt and yellow and may also cause distorted and stunted plant growth. Most aphid species will go through numerous generations during the growing season. Aphids also transmit virus diseases to many plants. There are a number of important species in Wisconsin. Image: Oklahoma State University ( source ) Asparagus aphid (Brachycorynella asparagi) The asparagus aphid is a recent import from Europe that causes a brooming distorted growth of the ferns of asparagus. It is bluish gray in color, and the cornicles aren’t readily apparent. Normally only isolated plants are affected and can be spot treated. Asparagus Aphid, Brachycorynella asparagi – Oklahoma State University web page Image: Eran Finkle, Flikr ( source ) Cabbage aphid (Brevicoryne brassicae) Cabbage aphids are gray in color and live in closely packed groups. Heavy infestations cause leaves to curl and may prevent head formation. Aphid damage is most serious on young cabbage and in the seedbed. Once cabbage heads form, this insect is difficult to control.

Image: Wikipedia ( source ) Green peach aphid (Myzus persicae) The green peach aphid is the most destructive and insecticide-resistant aphid in Wisconsin. Many crops are attacked including greenhouse transplants of pepper, tomato, and cabbage, along with beet, carrot, broccoli, Brussels sprouts, lettuce, eggplant, and potato. Green peach aphids are 1/8 inch long, yellowish green, peach, or dirty red in color, and can be found on the undersides of leaves. This aphid is a very efficient vector of many virus diseases. Scouting is usually done by examining the undersides of leaves and looking for aphid activity. In potatoes, remove 25 leaves per sample from the lower half of 25 different plants, with at least 10 sample sites per field. Treat if more than 10 aphids are found per 100 leaves in seed fields or more than 30 per 100 leaves in table stock or processing potatoes. Green Peach Aphid, Myzus persicae – Oklahoma State University web page Image: Univ.

of Tennessee ( source ) Melon aphid (Aphis gossypii) Melon aphid is a small dark aphid that can be found building up on the undersides of leaves of cucumber, squash, pumpkin, and melon. They can produce up to 10 generations per year and cause infested plants to yellow and wilt. Low numbers are most often controlled by natural enemies. Image: Washington State Potato Commission ( source ) Potato aphid (Macrosiphum euphorbiae) Potato aphids are larger than green peach aphids and come in both red and green. They attack eggplant, tomato, and potato and are most often found on young, actively growing tissue. To sample for potato aphids, remove leaves from the terminal parts of 35 plants and count the number of aphids. Repeat in at least 10 locations per field. When aphid counts exceed 20 per 100 in seed potato and 50 per 100 leaves in table or processing potatoes, control measures are suggested.

Image: University of Minnesota ( source ) Asparagus beetle (Crioceris asparagi) Common asparagus beetles are 1/5 inch long and orange with white dots on a dark background on the back. They overwinter as adults and emerge in April (earlier than the spotted asparagus beetle), and begin feeding and laying eggs on the spears. Spotted asparagus beetle adults may feed on spears but do not begin laying eggs until the plants have ferned out. When both species are present, both the spears and ferns can be heavily damaged. Asparagus beetle – UW-Extension garden facts Asparagus beetle – University of Minnesota fact sheet Vegetable crop news: wasp attacks asparagus beetle – Michigan State University web page on the parasitoid Tetrastichus asparagi Image: Marlin E. Rice source Bean leaf beetle (Cerotoma trifurcata) The bean leaf beetle is 1/4 inch long, ranges in color from yellow-green to red, and features four black spots in its back. Adult feeding can reduce plant vigor and yield by chewing small holes in leaves. Adults also feed on developing pods, causing distortions and making them more prone to infection from pathogens.

Larvae feed on roots, nodules, and below-ground stems. Adult bean leaf beetles overwinter in leaf litter close to fields where beans were planted the previous growing season. They become active in May or June, and often migrate to bean fields after the first cutting of nearby alfalfa. Two generations of adults are usually produced in southern Wisconsin before the beetle overwinters. To discourage overwintering adults, destroy plant debris and keep vegetation mowed near bean crops. Otherwise, an imidacloprid insecticidal seed treatment at planting should be used by growers who have had problems with the beetle in the past. Bean leaf beetle – UW-Extension Field Crops Pathology Soybean Plant Health Image: Wikipedia ( source ) Colorado potato beetle (Leptinotarsa decemlineata) The Colorado potato beetle is the most distinctive pest of potatoes. Both the yellow-and-black striped adults and the brick-red humped larvae feed on the foliage. Feeding normally is initiated on the terminal growth and can be severe. Adults overwinter and move to emerging potatoes early in the spring (May). The adults lay bright yellow egg masses, and larvae feed for several weeks in the summer before pupating in the soil.

Emerging adults then continue feeding throughout the season until no vines remain. Image source Cucumber beetles (genus Diabrotica) The striped and spotted cucumber beetles are 1/4-inch, yellow-green beetles that become active in very early spring. Adults feed on developing fruit and foliage and,more importantly, transmit bacteria causing wilt disease. Small numbers of beetlescan devastate a planting if they carry the disease, and they must be controlled before the disease appears. In the fall, adults of these beetles can chew holes in the developing fruit of vine crops such as cucumber, melon, pumpkin, and squash. New options for cucumber beetle control in cucurbit crops: review of corn earworm & tomato fruitworm management – UW Extension PowerPoint Flea beetles Flea beetles are frequently a pest of early plantings. These small, shiny black beetles, which jump when approached, chew small circular holes in the leaves. This damage is insignificant on large potatoes and tomatoes but young seedlings can be rapidly killed.Young seedlings or transplants of cabbage, broccoli, beet, tomato, eggplant, and all vine crops should be scouted on a weekly basis when they are young.

If flea beetle activity is seen, an insecticide rescue treatment will be needed. Flea beetles – UW-Extension garden facts Flea beetles – Colorado State University fact sheet Flea beetles: Organic control options – ATTRA publication Japanese beetles (Popillia japonica) Japanese beetle adults are 3/8 inch long and a metallic green color, with copper wing covers and a series of white dots along the side of the abdomen. The larvae are a serious pest of turfgrass in late summer. Adults are active from late June to September and feed on the flowers, fruits, and leaves of a wide variety of plants, including asparagus, tomato, and eggplant. Trapping measures may actually attract more beetles and cause more damage. Image: University of Illinois ( source ) Common stalk borer (Papaipema nebris) Eggs of this cutworm relative are laid in grassy weeds in September. In late May to July, the brown-and-white striped caterpillars migrate into fields and burrow into the stems of tomatoes, potatoes, beans, and other thick-stemmed plants. Once inside the stem, the insect cannot be controlled.

Fall grass control will prevent egg laying and is the best control method for common stalk borer. Image: UW Entomology ( sou rce ) European corn borer (Ostrinia nubilalis) European corn borer larvae are between 3/4 to 1 inch long and range in color from grey to creamy white, with a black head and numerous spots over the body. In most of Wisconsin, two generations of eggs are laid on the undersides of leaves. First generation larvae typically cause damage only to leaves and stalks, unless the corn is already tasseling, in which case the larvae will enter the ear. In Southern Wisconsin, begin checking early sweet corn for egg masses by June 15th. Second generation larvae develop from eggs laid in mid-August and cause heavy infestations in late-planted corn. Direct feeding on kernels may make sweet corn unmarketable. Moth populations can be monitored with blacklight traps. Scouting suggestions for both fresh market and processing sweet corn can be found here .

Image: Flickr user Katja Shulz ( source ) Tarnished plant bug (Lygus lineolaris) Plant bugs are 1/4 inch, tan to dark brown oval insects with piercing sucking mouthparts. They attack more than 50 different economic crops but are most damaging to strawberries, peppers, and all bean crops in Wisconsin. Feeding by these insects causes poor fruit set and gnarled fruit due to the toxic saliva they inject into the plant. They are highly mobile insects that overwinter in field debris. Large numbers of adult plant bugs migrate out of alfalfa fields when hay is cut. For both potatoes and commercial beans, take 25 sweeps with an insect sweep net per sample site with at least 10 sample sites per 100 acres. When counts exceed one tarnish plant bug per sweep on a field average, control measures are recommended in potato and snap bean. Leafhoppers Aster leafhopper (Macrosteles quadrilineatus) The aster leafhopper is an olive, wedge-shaped insect that is 1/6 inch long and has six black spots on the vertex of the head.

This leafhopper also migrates from southern states and carries the pathogen that causes carrot (aster) yellows disease. Aster yellows can be a serious problem on carrot, lettuce, celery, onion, and potato. For most crops, it is important to control the disease before symptoms show in the field. For susceptible crops such as lettuce and celery, one or two insecticide applications per week may be needed from seedling stage until harvest. (See “ Aster Yellows Index “) Images and information Potato leafhopper (Empoasca fabae) Potato leafhoppers are small (1/8 inch) wedge-shaped, bright green insects that blow up into the state every spring from the southern states. They may arrive anytime from late May to early July. Potato leafhoppers have a toxic saliva that causes injury to many plants. Leafhopper feeding will cause leaf edges to curl and turn yellow, and leaves may eventually brown and die. This “hopperburn” is most serious on potatoes, dry beans, and snap beans. Fields should be scouted on a weekly basis to monitor for this pest. Potato leafhoppers are best sampled with a sweep net.

For potatoes, take 25 sweeps with an insect sweep net per sample site, and carefully turn over 25 leaves per sample site. Select leaves from the middle portion of the plant. Use at least 10 sample sites per 100 acres. Control measures are recommended when a field averages one to two adult leafhoppers per sweep and there are more than 15 nymphs per 25 leaves, or if there are three or more adult leafhoppers per sweep and nymphs are present. For snap beans, take 25 sweeps per sample site with at least 10 sample sites per 100 acres scattered throughout the field. Nymphs are less mobile and are best scouted by leaf samples. Carefully turn over 25 leaves per sample site and count nymphs. Select leaves from the middle of the plant and use at least 10 sample sites per 100 acres. If counts exceed one leafhopper per sweep and one nymph per 10 leaves, then control measures are recommended.

Image: Cornell University ( source ) Cabbage maggot (Delia radicum) The adult cabbage maggot is a small gray fly that lays its eggs at the base of crop plants in the cabbage family. The small, cylindrical white eggs hatch into legless white maggots that feed on the roots. Seedling plants can be killed rapidly, while transplants tend to wilt and die slowly. Root crucifers such as radish and turnip show surface tunneling that is often accompanied by soft rots. Chemical controls require either soil application to seed furrows or transplant drenches. However, these treatments last for only 4 to 5 days and must be applied when the adults are actively laying eggs. The cabbage maggot has three generations in Wisconsin. The first emergence of adults from overwintering pupae is the largest and most damaging, therefore you want to plant after the pupae have emerged. This emergence and the egg-laying peak may be predicted accurately by keeping track of the degree days. Cabbage maggots do not develop below 43°F (developmental threshold). Peak emergence of first-generation cabbage maggots occurs when 300 degree days have accumulated.

For more information, see “Calculating Degree Days.” If planting is necessary during the time of peak emergence, then insecticide treatments are recommended. Cabbage maggot – UW-Extension garden facts Cabbage maggot – University of MN web page Image: Wikipedia ( source ) Onion maggot (Delia antiqua) Onion maggots are small whitish larvae found in the bulbs of onions. The adult is a grayish fly that resembles the cabbage maggot. Onion maggots are a problem after a series of cool, wet springs. The most effective way to control these insects is to apply an insecticide in the furrow when planting. Image source Seedcorn maggot (Delia platura) Seed corn maggot is by far the most serious pest of all beans. The white legless maggot burrows into the seed or seedling, causing very poor seed germination and emergence, and/or stems without leaves (snake heads). The adult is a small grayish fly that looks identical to the cabbage maggot. This insect overwinters in the pupal stage in the soil and becomes active early in the spring. Heaviest plant damage occurs during cool damp weather, in heavy organic soils, and after peak adult flights.

There are five generations per year, but most severe damage occurs in May and June. Peak activity of each generation can be predicted using degree days (200, 600, and 1,000 degree days–with a base temperature of 39°F–for first, second, and third generations, respectively). But since damage is severe for each of the first three generations, it is seldom possible to avoid activity periods. You can reduce damage by planting seeds during good germinating weather, using seed treated with insecticide, or sowing seed in higher than normal numbers. Planting seeds too early or directly into manure frequently increases problems with this insect. Other crops attacked include peas, corn, vine crops, and crucifers, but beans are the preferred host. For other hosts, damage is most severe when plants are planted before the recommended date or during cool springs. Seed corn maggot – UW-Extension fact sheet Seed corn maggot – UW-Madison Field and Forage Crop Entomology web page Thrips Image: University of CA ( source ) Thrips are small 1/25-inch insects that cause whitish scratches or brownish blotches on plant leaves. Hot dry weather is correlated with severe thrips problems.

Thrips attack cabbage and cause a brownish scarring in the head of processing cabbage. Thrips must be controlled before the plant heads out in order to assure proper coverage and control. In onions the injury looks similar to both ozone injury and some diseases. Use large volumes sprays (100 gallons/acre) with a wetting agent for thrips control. A second treatment 5 to 7 days later may be warranted. White Grubs Image: Marlin Rice ( source ) This insect, which is the larval stage of the June beetle, has up to a 3-year life cycle. Because the adults lay eggs in grassy sodded areas, fields located in plowed-down sodded areas are most susceptible. The characteristic C-shaped grubs feed on the roots of most plants. They are most damaging to root crops such as carrots or potatoes. Tilling the soil to expose the larvae during the spring and fall helps reduce numbers. Granular insecticides can be worked in the soil before planting in areas where damage is expected. Established weed-free fields should have few problems. Image: Kevin Black ( source ) Armyworms Armyworms are dark caterpillars measuring up to 2 inches long.

They have a dark stripe running lengthwise on the side with a yellow stripe beneath. Dark and light stripes alternate along their back. Armyworms move up from grassy weeds within cornfields or migrate into cornfields from small grain or forage fields. They may hide in soil crevices and beneath clods by day. At night, they chew corn leaves and weaken plants. Corn earworm / Tomato fruitworm (Helicoverpa zea) These varicolored, smooth caterpillars are up to 2 inches long and feed mostly on ear tips. Insecticide treatment is necessary for early market sweet corn and for late-season canning or market sweet corn (silking after August 15). Corn earworm – UW-Extension fact sheet Corn earworm – UW-Madison Field and Forage Crop Entomology web page Tomato fruitworm – University of CA IPM website Image: UW Entomology ( source ) Corn rootworm (genus Diabrotica) Rootworm larvae are white with black heads and grow 1/2 inch long. Northern and western rootworm larvae cannot be differentiated in the field.

They feed on crown roots from June to August, causing corn to lodge and “gooseneck.” Rootworms are most serious in loam soils but are of little consequence in muck or non-irrigated sandy soils. The larvae are not a potential problem unless corn is planted on the same ground in a “rootworm area” for 2 or more years in succession. Annual crop rotation controls these insects, because eggs overwinter in the soil. The adult beetle of the northern rootworm is yellow to green. The western species is yellow with three black strips. Because rootworm adults congregate in ear tips to feed on silks, large populations in August can impair corn pollination. If there are five or more beetles per plant (check silks), cornfields should be treated during the early silk period. This appraisal should be made prior to 75% silking. Late-season corn borer and earworm treatments reduce adult rootworms and eggs. Other fields may receive an economic population of overwintering eggs if 0.75 or more adults per plant are present around mid-August.

Corn rootworm – UW-Madison Field and Forage Crop Entomology web page Corn rootworm – UW-Extension fact sheet Image: UW Entomology ( source ) Cutworms These are the larval stage (caterpillar) of night-flying moths. They are whitish gray to brown worms, ranging from 1/2 to 2 inches long. They feed almost exclusively at night and hide in the soil during the day. All cutworms curl to a characteristic tight ball when exposed, making them easy to identify. Most cutworms cut plants off at or slightly below the soil surface, making recent transplants especially susceptible. Eventually, plants become too thick and tough for cutworms to feed. Adult females are attracted to tall grasses for egg laying, and cutworm numbers tend to be higher in weedy or trashy fields. Almost all commercial vegetable crops such as asparagus, beets, onions, carrots, celery, and potatoes can be attacked by cutworms. It is very difficult to predict when and where an infestation will spring up, and pre-plant insecticide treatments will not control heavy cutworm infestations. Scouting fields on a weekly basis is the best method for monitoring cutworm activity.

If damaging populations are found, a “rescue” treatment will be needed. Bait formulations are the preferred treatment if conditions are dry, whereas both baits and sprays can be used when the cutworms are feeding at the soil surface. Hornworm, genus Manduca The tomato hornworm is a very large green worm (up to 3 inches) with a spine on the posterior end and white side stripes. The larva feeds on both foliage and fruit, and because each larva eats three to four times its weight in food daily, the damage appears dramatic. The adult stage of this insect is a gray hawk moth that is often mistaken for a hummingbird because it feeds on flowers. Because they are usually found in small numbers, hornworms rarely need control. Hornworms – UW-Extension garden facts Imported cabbageworm – University of MN website Image: University of IL ( source ) Wireworms (family Elateridae) This insect is the larval stage of the click beetle and, like the white grub, lays eggs in grassy areas. Wireworms are also troublesome in low, poorly drained areas. Weed control is the best preventative measure.

Control procedures for white grubs will also control wireworms. Potatoes and carrots are the most susceptible crops. Grassy or old sod fields will have high populations of wireworms. A soil insecticide should be worked in pre-plant in these fields. Wireworms – UW Extension garden facts COLORADO POTATO BEETLE | CropWatch COLORADO POTATO BEETLE Share This Page COLORADO POTATO BEETLE Of all the potato insects, the best known and most wide spread is the Colorado potato beetle (Leptinotarsa decemlineata). The Colorado potato beetle (CPB) was first observed in Nebraska and then identified in Colorado. It is a well known pest in both commercial fields as well as home gardens. Its host range encompasses all members of the Solanaceous family, such as potato, tomato, pepper, egg plant, and weeds such all nightshades and buffalo bur. It can be a pesky pest defoliating whole potato fields in some parts of North America. Description CPB undergo complete metamorphosis: adult, egg, larva, and pupa. Adults are hard-shelled with a round, convex shape.

Their forewings are yellow with a total of 10 black stripes running longitudinal. They are about a half an inch long. Adults eat foliage until they pupate. Eggs are oval, yellow to bright orange. They are layed in clusters of 10 to 30 eggs on the underside of leaves. Larvae are slug-like with a soft shell. They are red to orange to tan depending on age and they have two rows of black dots on each side. The body which is humped enlarges with time and grows in four size stages. Larvae eat foliage as they grow and this is the most destructive stage. Pupae are small and are found in the soil . Life Cycle Adults overwinter four to 12 inch deep in the ground of harvested potato fields and emerge in spring around May. Adults do not migrate but will fly for several miles to find its Solanaceous hosts. Besides potato, these include weeds such as nightshades and include garden crops such as tomato and pepper. Adults then mate and lay eggs on the host plants. Egg laying may last as long as a month and may be as many as 500 eggs on a single plant.

After four to 10 days depending on temperature, eggs hatch. The cooler the air temperature the longer it will take for hatching. The hatchlings are tiny larva. The larva grow in four progressive stages (instars), eating the host foliage all the while. Depending on temperature, the larval stages will last two to five weeks or when about 400 degree days have accumulated. Then, the larva will go into the ground, three to six inch deep, and pupate. The Pupa last for five to 10 days after which new adults emerge. The emerged adult travels around, looks for mates, and after seven to 10 days begins to lay eggs. The full cycle takes five to eight weeks per generation. Usually, there are two generations per season in Nebraska, early to mid June and early to mid August. In cooler States, less than two generations may occur. At the end of the season, remaining larva move into the soil and overwinter as pupa. Damage CPB larvae are the most damaging form but adults also feed on the foliage. Due to feeding, leaflets have holes of varying sizes usually starting around the margins.

The leaf blades are eaten often leaving a skeleton of veins and petioles behind. This results in defoliation. Defoliation threshold levels are reported as 25% before tuber bulking, 10% during the first half of bulking, four to six weeks and 25% after bulking. Vine damage results in yield loss due to loss of foliage to support tuber growth and mis-shaping of tubers is also possible. Severe damage may result in plant stunting as well. Scouting Monitoring the edges of fields, nearby gardens and surrounding weeds especially nightshades will give warning when CPB are entering the field. Since they are poor fliers, CPB enter a field along the edge usually at a corner that is closest to the previos year’s crop. Economic threshold levels have been reported. Management 1-3 2-4 * Values are numbers of larval-infested plants per 100 feet of row. Do not apply products unless the average infestation level is greater than these values. Bechinski, E.J., Sandvol, L.E., and Stoltz, R.L. 1994. Integrated Pest Management Guide to Colorado Potato Beetles.

Univ Idaho Coop Ext Circ #757. Mechanical The trench method is a semi-successful mechanical control of CPB mostly applicable to small acreage. In areas where close rotations are used or potatoes are grown adjacent to last years potato fields, this method may help to alleviate first generation CPB damage. A trench is plowed between overwintering sites and this year's potato field. The trench should be at least 12 inches deep with sides sloping 45 to 90o. Emerging beetles walk to find their early season hosts and become trapped in the trench. A fine coating of dirt on the plastic prevents the beetles from being able to get out of the trench. Note some CPB adults may fly over the trench; however, this method can be surprisingly effective at trapping beetles. Using a flamer is another mechanical method for controlling CPB. Its best fit is also in areas where trap crops are used to congregate immigrating beetles for easier control. Flaming is used on plants that are up to 8 inches tall with little adverse effects on them. Larger plants will provide more protection for the beetles and effectiveness is reduced.

Flaming involves using two propane-powered flame jets that are directed in an offset manner toward the row. A single unit can be bought for under $3,o00 or constructed. Propane usage is about 3½ to 5½ gallons per acre. Speed is also an advantage. As might be suspected, you don't want to go too slow with this type of machine. A speed of 4 to 6 mph is recommended. Control with the flamer should be done on a clear warm day so the beetles are up on the plants. Data for early-season control have been as high as 90% with this method. Moyer, D.D. 1992. Fabrication and operation of a propane flamer for Colorado potato beetle control. Cornell Coop Ext Bull. pp. 7. Olkowski, W., Saiki, N. and Daar, S. 1992. IPM options for Colorado potato beetle. The IPM Practitioner 14:1-21. Biological Several common beneficial insects, predators, are good agents for devouring CPB eggs and even attacking larva; see lady beetles and others.

Since CPB overwinter in potato fields, rotating crops is key and the following season’s potato fields should be planted a few miles away from the previous season’s potato fields. Since CPB will develop on weeds in the same family as potato, controlling these especially the various night shades is an important part of the management program. Bt products such as Dipel have been used to kill young CPB larvae but timing is crucial for efficacy. In the 1990s, potato clones began to be engineered (GMO) with Bt genes to protect plants from CPB. This technology is very successful in doing that but due to uninformed political pressure this GMO technology has been slowed on potato although common in corn and soybean. Chemical Most systemic insecticides applied at planting will kill the CPB's first generation. Most foliar insecticides will take care of later invasions by CPB. The key is not to let the population de-synchronize. If this happens, weekly applications of foliar insecticides could be needed. The best application stage is on the young larvae, first and second instar, because they have most of their eating ahead of them. Older larvae have less eating to do and also are less sensitive.

Killing adults works but the result may be so/so because they may have already laid eggs and you may be killing their predators such as lady beetles as well. These predators would devour the CPB egg masses. Since CPB enter fields along the edges and gradually move inwardly, with good scouting, often only the field’s perimeter needs to be treated. It is very important to note that the CPB is highly capable to develop resistance to insecticide products. On the East Coast and Great Lakes region, the CPB has developed resistance to combinations of products, multiple-resistance or “super” bugs. Therefore, management needs to be an integrated program of biological and chemical methods, at least until the consumer market allows resistant potato lines to return. Home Gardens To control CPB in garden potatoes as well as peppers and tomatoes, apply carbaryl (Sevin) to plants when the adults or young larvae are present. But be aware not to treat around flower areas to avoid killing honey bees needed for pollination.

Quick Review Colorado Potato Beetle: Organic Control Options | ATTRA | National Sustainable Agriculture Information Service Home > Master Publication List > Colorado Potato Beetle: Organic Control Options Colorado Potato Beetle: Organic Control Options George Kuepper © The Colorado Potato Beetle is native to North America and is the most important pest to potato crops in most areas of the United States. This publication discusses physical barriers and traps to control the beetle, as well as the use of flame applications. Biological and botanical controls are also discussed. Biopesticides based on the bacterium Bacillus thuringiensis (Bt) and on the fungal agent Beauveria bassiana are also reviewed. A reference and resource listing completes the publication. Table of Contents Additional Resources Introduction Colorado potato beetle (CPB), Leptinotarsa decemlineata, is native to North America. Its original range was restricted to the eastern part of the Rocky Mountains, where it fed on the buffalo bur, a plant of no economic importance. Once the potato was introduced to this region, the beetle quickly moved into the crop and began spreading eastward from potato patch to potato patch, reaching the East Coast by 1874.

The pest is now found throughout North America, except in parts of Florida, Nevada, California, and eastern Canada. The CPB is the most economically damaging pest to potatoes in most areas of the United States. If left uncontrolled, it can completely defoliate a potato crop. Although the potato is its favorite food, the beetle may also feed on tomato, eggplant, tobacco, pepper, ground cherry, petunia, and even cabbage crops. It also attacks a number of common weeds including jimson weed, henbane, horse nettle, belladonna, thistle, and mullein. ( 1 ) CPB has developed resistance to most registered pesticides, making it one of the most difficult insect pests to control. ( 2 ) The life cycle of the CPB varies according to where it is found. In northern Maine, it completes one generation per year; farther south it completes three generations per year. The adult beetles overwinter 12-18 inches below the soil surface in the potato field, and in protected sites around the field. The adults emerge in late spring, move into the field, establish themselves on a plant, and mate.

Females lay egg masses on the undersides of leaves in batches of approximately 25 eggs. A single female may lay up to 500 eggs. Because the eggs are laid in clumps, the larvae tend to be found in clumps as well. ( 2 ) Back to top Cultural and Physical Controls A combination of several strategies can help keep CPB populations under control. Crop rotation can delay CPB population buildup, but will not prevent an infestation unless fields are fairly well isolated. The effects of crop rotation and field proximity on populations of CPB and incidence of early blight (Alternaria solani) were quantified in a study done in the early 1990s. ( 3 ) The researchers noted that the infestations of both these pests were inversely related to the distances between rotated fields and the nearest locations where potatoes were planted the previous season. In other words, the farther this season's potato field is from last season's potato field, the fewer the pest problems. Research at Cornell University demonstrated the efficacy of flame technology in controlling overwintering CPBs. The most effective time for flaming is between plant emergence and 8 inches in height.

Taller plants are less heat-tolerant and the canopy shields many of the pests. Best control is achieved on warm, sunny days when beetles are actively feeding on top of the plants. In trials, flaming resulted in 90% control of overwintering adult CPB, whereas chemical insecticides provided only 25-50% control. Flaming also reduced egg hatch by 30%. ( 4 ) For more information on propane flame weeding, including specifications and sources of flame weeders, see the ATTRA publications Flame Weeding for Agronomic Crops and Flame Weeding for Vegetable Crops . CPB can be excluded from crops with the use of "floating row covers," a thin fabric spun from a synthetic material. The product allows air and moisture to travel through it, while preventing pest species access to the plants. For more information on row covers, see the ATTRA publication Season Extension Techniques for Market Gardeners . Another exclusion strategy is the use of plastic-lined trenches as a barrier to CPBs entering a potato field. ( 5 ) Beetles can walk on clean plastic mulch at an angle, but once the plastic is coated with fine soil particles, this becomes impossible.

Trenches with walls sloping at greater than 46° will retain an average of 84% of all adults caught under field conditions. A potato field surrounded by plastic-lined trenches might see its population of overwintered adult beetles reduced by nearly half. Small numbers of beetles escape from the trenches during periods of rain, but once the plastic dries, footing again becomes impossible for the insects. Further details on this strategy are presented in the 16-minute video from Cornell Cooperative Extension, mentioned above. In a similar vein, Canadian researchers have developed a portable field-edge trap to keep CPBs from entering potato or tomato fields after overwintering. ( 6 ) The first prototype was constructed from sheet metal, and a subsequent version was made of extruded plastic. The design, which received a U.S. patent, makes it easy for beetles to crawl up the sides, where they eventually fall into the trap. Dozens of CPBs per linear foot were trapped during field tests. According to another study, mulching with wheat or rye straw may reduce the CPB's ability to locate potato fields, and the mulch creates a microenvironment that favors CPB predators.

( 7 ) In the first half of the season, soil predators—mostly ground beetles—climb potato plants to feed on second- and third-instar larvae of the CPB. In the second half of the season, ladybird beetles and green lacewings are the predominant predators, feeding on eggs and on first and second instars. Mulched plots supported greater numbers of predators compared to non-mulched plots, resulting in significantly less defoliation by CPB. Tuber yields were increased by a third. A mechanical strategy that stimulated considerable interest in the late 1980s and early '90s was the bug vacuum. These were rather large, tractor-drawn machines that sucked insects from the crop plants and killed them, usually by shattering them against the fan housing. One particular unit—the beetle eater—was intended for use on CPB in potatoes. Interest in insect vacuums was not long-lived. Problems were noted with soil compaction, loss of beneficial insects, and lack of efficacy on heavier pests deep within crop canopies. ( 8 ) A few machines, however, remain in commercial use.

( 9 ) For further information, see the ATTRA publication Bug Vacuums for Organic Crop Protection . Back to top Varietal Resistance Several genetically-engineered potato varieties are available to commercial growers, but these are not permitted in certified organic production. A few traditional potato varieties (e.g., 'Russet Burbank') seem to be more tolerant of CPB than others, but none of them can be considered "resistant." The April 1989 issue of National Gardening highlighted research on planting early-maturing varieties that develop potato tubers before CPB populations explode. ( 10 ) It lists seven varieties that mature in 75 to 88 days—Caribe, Norland, Pungo, Redsen, Sunrise, Superior, and Yukon Gold—and illustrates the growth stage of the potatoes versus CPB emergence and larval development. This practice may prove especially beneficial to growers in northern regions, where cooler temperatures slow insect development. Back to top Biological Control CPB has several natural enemies, but they are rarely seen in commercial potato fields because of heavy pesticide use and lack of habitat to support them. Even under organic growing conditions, where natural enemies are more abundant, they will probably not completely control the CPB.

The generalist predators—ladybird beetles, lacewings, predatory stink bugs, spiders, etc.—provide some control. There are also a number of CPB parasites. Doryphorophaga doryphorae and D. coberrans are two species of fly that parasitize CPB larvae; a wasp, Edovum puttleri, parasitizes eggs. Increasing habitat for natural enemies by providing pollen and nectar sources along field borders or by planting insectary strips in the field can increase the effectiveness of these biological controls. ATTRA has more information on this technique in the Farmscaping to Enhance Biological Control publication. As mentioned above under Cultural and Physical Controls , mulching also favors CPB predators. Back to top Botanicals A few commercial botanical preparations are available for use on CPB. Rotenone is derived from the roots of a South American plant. Since it is somewhat slow at killing pests, it is often combined with pyrethrum for a faster "knockdown." Plant protection is relatively brief, usually lasting two days or less. Rotenone must be used with caution as it is quite toxic to fish and swine.

Rotenone is a restricted material, one that should be used only when other, less severe options fail to exert adequate control. Be certain to read the label directions for specific instructions and cautions. Various products with the active ingredient azadirachtin (from neem tree seeds) have some efficacy against CPB in the early crop stages. These include Neemix™, BioNeem™, and Margosan-O™. However, spray concentrations of 1% and greater may cause phytotoxicity on potato plants. ( 11 ) Furthermore, though they were once considered benign to beneficial insects, neem products have demonstrated some negative impacts. Washington State research has found neem to be toxic to ladybeetles, especially in their early larval stages. ( 12 ) Meanwhile, research in Maine found neem less effective than Bacillus thuringiensis (see Biopesticides below). ( 13 ) Pyola™ is a natural insecticide product that combines canola oil with pyrethrins. It is recommended for use on cucumber beetles, flea beetles, Mexican bean beetles, squash bugs, aphids, mites, and CPB.

( 14 ) However, since much of the canola oil on the market is derived from genetically engineered plants, this product may or may not be acceptable for organic production. Growers should contact their certifying agent before purchase and use. A number of herbs and herbal extracts are also reputed to repel or inhibit CPB, though research has been far from thorough. Among the plants believed to have some effect are: catnip, tansy, sage ( 15 ), hemp ( 16 ), oak extract ( 17 ), wild potato (Solanum chacoense) ( 18 ), and citrus oils. ( 19 ) Back to top Biopesticides Several biopesticide products based on the bacterium Bacillus thuringiensis (Bt) have become available in recent years. M-One™, made from B. thuringiensis ssp. san diego, is genetically engineered and therefore is not allowed in certified organic production. Novodor™, produced by Valent USA Corp. ( 20 ), contains B. thuringiensis ssp. tenebrionis, a form of Bt that is not genetically engineered and can be used by organic producers in most states.

One source of Novodor is Peaceful Valley Farm Supply. ( 21 ) Bt is effective only if ingested by the pest, and then only in the larval stage. Furthermore, Bt sprays are generally effective only against newly hatched CPB larvae. Applications should be made within one to two days whenever one or both of two criteria are met: densities of egg masses reach or exceed 4 per 50 vines and at least 25% of the oldest masses have hatched or are hatching; densities of small larvae reach the treatment threshold of 76 per 50 plants or stems. ( 22 ) Bt is most effective if applied when daytime temperatures reach or exceed 75°F, because larval feeding is then increased. ( 22 ) Another biopesticide, Mycotrol™, is based on the fungal agent Beauveria bassiana. Like Bt, B. bassiana is a naturally occurring organism. Unlike Bt, B. bassiana is effective against all larval and adult stages of CPB. Furthermore, once B. bassiana is applied, it can continue to propagate and provide a significant level of CPB control throughout the remainder of the season.

The most significant limitation of B. bassiana appears to be its sensitivity to high temperatures. Mycotrol works best between 70 and 80°F. Growth of the organism is much slower at warmer temperatures. ( 23 ) As a result, this may be a poor option for growers in southern states during much of the growing season. Emerald BioAgriculture Corp. ( 24 ), the manufacturer of Mycotrol™, recommends spraying when hatching occurs in 20-25% of the egg masses—timing similar to that for Bt. A possible strategy involves combining Bt with B. bassiana for optimum efficacy. While Bt is effective at killing early-instar larvae, it will also slow the growth of larger larvae and make them more susceptible to the fungus. ( 23 ) Parasitic nematodes are another control option. Commercial formulations of Heterorhabditis species are available and have been shown to be more pathogenic ( 25 ), to the CPB than Steinernema species of nematodes, which are also commercially available. Back to top References Metcalf, R.L., and R.A. Metcalf. 1993.

Destructive and Useful Insects, 5th ed. McGraw-Hill Book Co., New York, NY. p. 14.43-14.45. Hollingsworth, Craig S., et al. (ed.). 1986. Potato Production in the Northeast: A Guide to Integrated Pest Management. Cooperative Extension, University of Massachusetts, Amherst, MA. p. 355. Weisz, R., et al. 1994. Distance rotation and border crops affect Colorado potato beetle (Coleoptera: Chrysomelidae) colonization and population density and early blight (Alternaria solani) severity in rotated potato fields. Journal of Economic Entomology. June. p. 723-729. Moyer, Dale. 1992. Fabrication and Operation of a Propane Flamer for Colorado Potato Beetle Control. Cornell Cooperative Extension—Suffolk Co., Riverhead, NY. February. 7 p. Boiteau, G., et al. 1994. Development and evaluation of a plastic trench barrier for protection of potato from walking adult Colorado potato beetles (Coleoptera: Chrysomelidae).

Journal of Economic Entomology. October. p. 1325-1331. Anon. 2001. Field-Edge Trap for Colorado Potato Beetles. HortIdeas. March. p. 32–33. Brust, G.E. 1994. Natural enemies in straw-mulch reduce Colorado potato beetle populations and damage in potato. Biological Control. Vol. 4, No. 2. p. 163–169. Moore, Jim. 1990. Sweeping fields controls some pests. American Vegetable Grower. March. p. 10–11. Birt, Kathy. 2000. Bug off! Spudman. May-June. p. 26–27. Ruttle, Jack. 1989. Speedy spuds beat beetles. National Gardening. April. p. 55–57, 76, 77. Olkowski, Wm., et al. 1992. IPM options for Colorado potato beetle. The IPM Practitioner. September. p. 1–21. Banken, Julie, and John Stark.

1998. Multiple routes of pesticide exposure and the risk of pesticides to biological controls: A study of neem and the sevenspotted lady beetle (Coleoptera: Coccinellidae). Journal of Economic Entomology. Vol. 91, No. 1. p. 1-6. Murray, Kathleen. 1997. Utilization of a Neem Product in a Reduced Synthetic Chemical Insecticide Management Program for Colorado Potato Beetle. Sustainable Agriculture Network. November. Anon. No date. Pyola™. Gardens Alive Online Store. Grossman, Joel. 1989. Herbal folklore tested. Common Sense Pest Control. Spring. p. 4. Anderman, Robbie. 2000. Hemp leaf tea discourages potato bugs. Eco-Farm & Garden. Winter. p. 29. Williams, Greg, and Pat Williams. 1986. Oak extracts inhibit Colorado potato beetle feeding. HortIdeas. August. p. 86. Williams, Greg, and Pat Williams. 1988. Leptine vs. Colorado potato beetles. HortIdeas. February. p. 15.

Ellis, Barbara, and Fern Marshall Bradley. 1992. The Organic Gardener's Handbook of Natural Insect and Disease Control. Rodale Press, Emmaus, PA. p. 471. Valent USA Corp. 1333 N. California Blvd., Suite 600 Walnut Creek, CA 94596 Jones, Richard. 1999. Bad news for beetles. American Vegetable Grower. February. p. 12, 14. Emerald BioAgriculture Corp.

Question: The Colorado Beetle is a destructive pest of which crop?
Answer: POTATO