BIOLOGICAL CONTROL OF WHITEFLIES AND OTHER PESTS WITH A FUNGAL PATHOGEN

Abstract: The subject invention concerns a novel biopesticide and its use to control whiteflies and other pests which cause a significant amount of damage to plants throughout the United States and the Caribbean. These pests are particularly destructive in greenhouses and nurseries. A virulent isolate of Paecilomyces fumosoroseus in an agricultural composition, can be used to effectively control these insects. Exemplified herein is Paecilomyces fumosoroseus Apopka, ATCC 20874. By using this novel fungus, or mutants thereof, whiteflies and other pests can be controlled without the environmental and public safety hazards presented by chemical control agents.

Description: BIOLOGICAL CONTROL OF WHITEFLIES AND OTHER PESTS WITH A FUNGAL PATHOGEN Background of the Invention Whiteflies, mites, aphids, thrips, mealybugs, an other pests cause millions of dollars of damage each yea to ornamental plants and plants grown in greenhouses. Fo example, the sweetpotato whitefly Bemisia tabac (Gennadius) has appeared on poinsettias in California, Florida, Georgia, and North Carolina. During 1981, B. tabaci was responsible for crop and market losses of $10 million in cotton, cucurbits, and lettuce in California an Arizona. The whitefly is increasingly a problem in Florid where, in 1986, B. tabaci caused approximately $2 millio of damage to Florida's $8 to 10 million poinsettia crop. B. tabaci is also a pest of international importance, having been found on host plants throughout the mid-eas Caribbean and Central America. This insect is now known t feed on more than 500 different plants, many of which ar of importance in the Caribbean and Florida. For example cassava, sweet potato, squash, tomato, beans, lettuce cotton, pepper, carrot, cucumber, egg plant, and watermelo are all known hosts. This species of whitefly severel impacts infested plants by its feeding, production o honeydew with resultant growth of sooty mold, an transmission of plant pathogens. Most extensive losses t this pest have been through direct feeding damage an indirect damage through transmission of plant diseases. Whitefly borne diseases are of major importance i tropical and subtropical agriculture. More than 7 diseases caused by viruses and microorganisms are known t be transmitted by whiteflies, with most of them bein transmitted by B. tabaci. In Puerto Rico, this whitefly i a vector of at least seven diseases. One of these diseases is the bean golden mosaic virus, a disease affecting many legumes. B. tabaci (Gennadius) has proven to be very difficult to control with conventional pesticide applications. Many factors contribute to the lack of control obtained with pesticides. The most important factor is that this whitefly has demonstrated a broad spectrum of resistance to chlorinated hydrocarbon, organophosphorus, carbamate, and synthetic pyrethroid insecticides. Very few commercially available pesticides are effective against whiteflies, and those which do work are only effective if care is taken to make a very thorough application of the insecticide several times a week. The sweetpotato whitefly spends most of its life on the undersides of leaves, therefore, growers must adjust their management practices to permit increased pesticide coverage there. The spacing of the plants must be such that the chemical spray can penetrate the canopy and reach all surfaces of the plants. In addition to being largely ineffective, and difficult and costly to apply, chemical control of these pests has other significant drawbacks. For example, the use of chemical pesticides presents the further disadvantages of polluting the environment, creating potential health hazards to agricultural workers and to consumers, development of resistance to chemicals in target pest species, detrimental effect of these chemicals on non- target species resulting in secondary pest outbreaks, and phytotoxic reactions by treated plants. Because of the problems associated with the use of chemical pesticides, safer and more effective methods of control for pests are clearly needed. Although biological control agents are actively being sought-after, to date no biological control agent has been commercially successful for the control of this whitefly. Biological control agents are needed not only for B. tabaci, but also for other common pests of greenhouse and ornamental plants. These other common pest include mites, thrips, mealybugs, aphids, and scales. Twospotted spider mites, for example, feed on many species of plants and are a major pest of vegetables, ornamentals, fruit trees, hops, cotton, and strawberries. It is believed that widespread use of broad-spectrum insecticides destroy or greatl hamper natural enemies of spider mites and may thereb allow pest outbreaks to occur. Biological control agents have been tried for many, i not all, of these pests. However, availability, limite host range, cost and reliability have reduced the potentia for implementing the use of these biological contro agents. The development of broad spectrum mycoinsecticide will reduce the need for many of the petrσchemically base pesticides. By using fungi to control pests, the potentia for resistance development is minimized, which, in turn, will stabilize many of the pest management programs. Brief Summary of the Invention The subject invention concerns the use of a novel, highly virulent Paecilomyces fumosoroseus to control pest which attack ornamental plants and plants grown i greenhouses. Specifically exemplified herein is £ fumosoroseus Apopka. This fungus, advantageously, show virulence against whiteflies, mites, aphids, thrips mealybugs, and other pests. Also, the use of the claime biological control agent does not produce the environmenta hazards associated with chemical control agents. Th fungus can be applied directly to the insects or it can b applied to the plants which are to be protected. Th fungus can be used in greenhouses, nurseries, or any othe place that whiteflies, mites, aphids, thrips, mealybugs and other pests are a problem. The subject invention als includes mutants of P_. fumosoroseus Apopka which substantially retain the virulence of the parent strain against nursery and greenhouse pests. Detailed Description of the Invention A biologically pure culture of a novel isolate of Paecilomyces fumosoroseus of the subject invention, designated Apopka, has been deposited in the American Type Culture Collection (ATCC), 12301 Parklawn Drive, Rockville, MD 20852. Culture Accession number Deposit Date Paecilomyces fumosoroseus Apopka ATCC 20874 February 4, 1988 The subject culture has been deposited under conditions that assure that access to the culture will be available during the pendency of the patent application to one determined by the Commissioner of Patents and Trademarks to be entitled thereto under 37 CFR 1.14 and 35 USC 122. The deposit is available as required by foreign patent laws in countries wherein counterparts of the subject application, or its progeny, are filed. However, it should be understood that availability of a deposit does not constitute a license to practice the subject invention in derogation of patent rights granted by governmental action. Further, the subject culture deposit will be stored and made available to the public in accord with the provisions of the Budapest Treaty for the Deposit of Microorganisms, i.e., it will be stored with all the care necessary to keep it viable and uncontaminated for a period of at least five years after the most recent request for the furnishing of a sample of the deposit, and in any case, for a period of at least 30 (thirty) years after the dat of deposit or for the enforceable life of any patent whic may issue disclosing the culture. The deposito acknowledges the duty to furnish a sample when requested, due to the condition of the deposit. All restrictions o the availability to the public of the subject cultur deposit will be irrevocably removed upon the granting of patent disclosing it. The taxonomic description of the novel isolate o Paecilomyces fumosoroseus claimed here is the same as tha for other members of that species. See Samson (Samson, R.A. [1974] "Paecilomyces and some allied Hyphomyces, Stud. Mycol. 6:1-116) for a taxonomic description of P. fumosoroseus♦ The novel isolate claimed here, Paecilomyce fumosoroseus Apopka, differs from other members of tha species metabolically and biochemically in such a way tha it is virulent against a number of important pests, a described below. The novel fungus of the subject invention has bee successfully grown on several different media includin potato dextrose agar (PDA), v-8™ juice agar, lima bea agar, oatmeal agar, and mixed cereal agar. Based on th diameter of the colonies, the spore production, and th cost and availability of the agars, Difco PDA™ and V-8 provide the best mediums for growing the fungus of th subject invention. Colonies on PDA are very fast growin with multinuclear colonies developing on the same plat shortly after the first sporulation occurs. A diameter o 4 cm. is obtained within 14 days at 24 C. When whiteflies or other pests are exposed t Paecilomyces fumosoroseus the insects are killed when th fungus colonizes the insect. The fungus has been shown t colonize all life stages of the target insects thereb facilitating immediate and long-term control of the pests Table 1 shows the results of experiments accessing th fungus' ability to infect the pupae of B. tabaci. Th treatment group involved in these experiments was treated with Paecilomyces fumosoroseus Apopka at a concentration of 1 x 10" spores/ml. The control group was not treated with the fungus and were dipped in a 1.2 g/500ml CAPTAN™ (Orthocide) solution to kill all contaminants. Table 1. Infection rate of 50 papae of B. tabaci after treatment with 1 x 10 6 spores/ml solution of Paecilomyces fumosoroseus Apopka. Days post- ■treatment % infection control treatment 3 0 64 5 0 76 6 0 82 7 0 86 Results of experiments assessing the fungus' ability to colonize the larvae of 2 species of whitefly—Bemisia tabaci (sweet potato whitefly) and Dialeurodes citri (citrus whitefly)—are shown in Table 2. Table 2. Colonization of Sweet Potato Whitefly, Bemisia tabaci and Citrus Whitefly, Dialeurodes citri by the novel fungus Paecilomyces fumosoroseus Apopka. Concentration % of Bemisia % of Dialeurodes (# spores/ml) tabaci colonized citri colonized —none 0 0 1 x 10 6 39 27 5 x 10 6 41 38 1 x 10 7 73 50 In addition to whiteflies, the fungus claimed here has also been observed to have activity against Thrips tabaci (onion thrips), Spodopter littoralis, Spodoptera xigua (beet army worm), Leptinotarsa decemllneata (Colorado potato beetle), Lymantria dispar (Gypsy moth), Tetranychus urticae (Twospotted spider mite), Frankliniella (flower thrips), Echinothrips americanus, Planococcus citri (Citrus mealybug), and Phenaococcus solani (Solanum mealybug). Advantageously, the fungus of the claimed invention is not adversely affected by most chemical control agents. As Table 3 shows, very few of the commonly used chemical control agents show activity against the fungus. This means that the fungus can be used before, after, or in conjunction with chemical control agents. The chemical pesticides listed in Table 3 are all trade names known to persons in the pesticide art. Table 3. Activity of common chemical pesticides against the fungus Paecilomyces fumosoroseus. Activity against Chemical pesticide P. fumosoroseus Apopka Aliette 80% WP NO Avid NO Bayleton 25% WP NO Benlate 50% WP NO Bo ran 75W NO Carbamate 76% NO Chipco 26019 (50 WP) NO Cyprex 65% WP NO Daconil 2787 75% WP NO Dursban 50W NO Flutolanil NO Kocide 101 (77%) NO Lesan (35%) NO Manzate 200 (80%) WP YES Ornalin 50 WP NO Orthocide 50W YES Orthene NO Prσchloraz YES Spotless NO Subdue 2E NO Sufers Insecticidal Soap NO Sulfur NO Talstan 10 WP NO Terraclor 75% WP NO Terraguard YES Truban 30% WP NO Vitavax NO Vydate 2L NO Zineb NO Zyban 75% WP NO 1 Spraying is the preferred method of applying the fungus of the claimed invention. The fungus may be applied to insects directly, to the foliage of plants, or the surroundings. A fungal suspension containing from about 1 x 10 5 to about 1 x 10^ spores per milliliter of water and 2 drops of TWEEN™ per liter can be sprayed either on the insect or on the plants which are to be protected. The TWEEN™ acts as a wetting agent and other equivalent wetting agents can be used. In order to prepare the fungus for application, the spores can be harvested from a culture by pouring 0.05% TRITON™ in the petri dish and then diluting with sterile deionized water. The fungus may also be applied in conjunction with a powder or granular carrier. As with spray application, the powder or granular formulation may be applied directly to the insect, the foliage of the plants, or the surroundings. To prepare the fungus for mixing with the powder or granular carrier it may be scraped or otherwise removed from the surface of the growth medium and combined with rice or any other granular or powder material which does not inhibit the growth of the fungus. Although the fungus may be applied in conjunction with a granular carrier, application may be easier and more uniform if the carrier and fungus mixture has a powder consistency. If necessary to achieve a particle size appropriate for easy application, the fungus/particle mixture may be slowly ground until the desired consistency is achieved. This means of formulation results in the application of a mixture which comprises fungal spores and mycelia together with a carrier. The presence of both the spores and the mycelia facilitates rapid and widespread colonization of the target insects. The application of the fungus and powder carrier can be accomplished using an aerosol applicator.

Claims: Claims 1. A Paecilomyces fumosoroseus characterized as having the property of being virulent against Bemisia tabaci, Dialeurodes citri , Thrips tabaci, Spodoptera littoralis, Spodoptera xigua, Leptinotarsa decemlineata, Lymantria dispar, Tetranychus urticae, Frankliniella, Echi no thrips americanus , Planococcus citri , and Phenaococcus solani . 2. A Paecilomyces fumosoroseus , according to claim 1, which, when in its essentially biologically pure form, has the identifying characteristics of Paecilomyces fumosoroseus Apopka culture deposit ATCC 20874, and mutants thereof . 3. A composition for controlling a pest selected from the group consisting of Bemisia tabaci , Dialeurodes citri, Thrips tabaci, Spodoptera littoralis, Spodoptera xigua, Leptinotarsa decemlineata , Lymantria dispar, Tetranychus urticae , Frankliniella , Echinothrips americanus , Planococcus citri, and Phenaococcus solani, comprising Paecilomyces fumosoroseus , characterized as having the property of being virulent against Bemisia tabaci , Dialeurodes citri , Thrips tabaci, Spodoptera littoralis, Spodoptera xigua, Leptinotarsa decemlineata , Lymantria dispar, Tetranychus urticae, Frankliniella, Echinothrips americanus , Planococcus citri, and Phenaococcus solani, in association with an agricultural carrier. 4. A composition, according to claim 3, wherein said Paecilomyces fumosoroseus , when in its essentially biologically pure form, has the identifying characteristics of Paecilomyces fumosoroseus Apopka culture deposit ATCC 20874, and mutants thereof . 5. A composition, according to claim 3, wherein th agricultural carrier is a liquid, a powder, granules, o small particles. 6. A composition, according to claim 5, wherein th liquid comprises water and a wetting agent. 7. A composition, according to claim 3, wherein th agricultural carrier comprises rice or ground-up rice. 8. A composition, according to claim 3, wherein sai agricultural carrier is liquid and said Paecilomyce fumosoroseus is in the spore form at a concentration o from about 1 x 10^ spores/ml carrier to about 1 x 10- spores/ml of carrier. 9. A composition, according to claim 3, wherein sai Paecilomyces fumosoroseus, when in its essentiall biologically pure form, has the identifying characteristic of Paecilomyces fumosoroseus Apopka culture deposit ATC 20874, and mutants thereof. 10. A composition, according to claim 3, wherein th agricultural carrier is rice and said fungus is present i the form of spores and/or mycelia. 11. A process for controlling a pest selected fro the group consisting of Bemisia tabaci, Dialeurodes citri Thrips tabaci, Spodoptera littoralis, Spodoptera xigua Leptinotarsa decemlineata, Lymantria dispar, Tetranychu urticae, Frankliniella, Echinothrips americanus Planococcus citri, and Phenaococcus solani, which comprise applying a Paecilomyces fumosoroseus, characterized a having the property of being virulent against Bemisi tabaci, Dialeurodes citri, Thrips tabaci, Spodoptera littoralis, Spodoptera xigua, Leptinotarsa decemlineata, Lymantria dispar, Tetranychus urticae, Frankliniella, Echinothrips americanus, Planococcus citri, and Phenaococcus solani onto said pests, the foliage of plants, or the surroundings. 12. A process, according to claim 11, wherein said Paecilomyces fumosoroseus, when in its essentially biologically pure form, has the identifying characteristics of Paecilomyces fumosoroseus Apopka culture deposit ATCC 20874, and mutants thereof. 13. A process, according to claim 11, wherein said fungus and a liquid carrier is applied directly to individual pest or to small groups of pests. 14. A process, according to claim 11, wherein said fungus is applied, along with a liquid carrier, directly to the foliage of plants. 15. A process, according to claim 11, wherein said fungus is applied, along with a powder, small particles, or granular carrier, directly to the foliage of plants. 16. A process, according to claim 11, wherein said fungus is used to control whiteflies. 17. A process, according to claim 11, wherein the target pests are mealybugs. 18. A process, according to claim 11, wherein the target pests are of the order Diptera. 19. A process, according to claim 11, wherein the target pests are of the order Hymenoptera. 20. A process, according to claim 11, wherein the target pests are of the order Lepidoptera.

Inventors: OSBORNE LANCE S, OSBORNE, LANCE, S.
Applicants: UNIV FLORIDA, UNIVERSITY OF FLORIDA RESEARCH FOUNDATION, INCORPO
Application year: 1989
Main classification: C12N1
IPC codes: A01N63, C12N1, C12R1