bluuebunny/crossref_metadata_2025_split huggingface dataset:
Susceptibility of the summer fruit tortrix moth, Adoxophyes orana (Lepidoptera: Tortricidae), to chlorpyrifos and strategies for insecticidal control in orchards
Authors: CROSS J V 
Published: February 2008

SummaryThe susceptibility of populations of the summer fruit tortrix moth, Adoxophyes orana, from apple orchards in Kent, England, to chlorpyrifos was determined in 1992, 1994 and 1995, by topically dosing larvae feeding on leaves or adults adhered to pheromone trap sticky bases. LD50 values (range 6.3 to 23.2 ng chlorpyrifos per individual) for first or second generation males, second generation females or for first generation fourth instar larvae collected in the field were significantly greater (2–3 fold) for populations from orchards with a long history of treatment with broad‐spectrum organophosphorous and other insecticides than for those from untreated orchards (range 1.6 to 8.1 ng chlorpyrifos per individual), though there was considerable variation between sites and years.Twelve replicated orchard experiments between 1993 and 1995 were used to examine a range of different strategies for insecticidal control. Applications of chlorpyrifos against overwintered larvae feeding in trusses in spring gave, at best, a 75% reduction in larval numbers, insufficient to prevent damage by the subsequent generation in summer. However, two applications of fenoxycarb (one immediately pre‐and one immediately post‐blossom of apple cv. Cox) completely prevented successful subsequent development of the pest, and a single (post‐blossom) spray nearly so.The timing of application of chlorpyrifos against first generation larvae hatching from eggs in June was shown to be critical and currently used methods of spray‐timing were unreliable. The effective persistence of chlorpyrifos was short (< 7 days). Though good control could be achieved with a single spray, a better strategy was to apply a series of sprays at 7‐day intervals to cover the egg hatch period. Sprays of Bacillus thuringiensis at the same timing intervals gave, maximally, an 80% reduction in larval numbers, but usually less: improved control was not achieved by applying a programme of sprays compared to a single spray, though a novel, more potent, formulation was significantly more active. Triazophos was also effective as an egg hatch spray. Sprays of chlorpyrifos or tebufenozide between late September and mid‐October 1995 against second or third instar larvae migrating to overwintering sites before diapause, failed to reduce significantly the numbers of subsequent overwintering larvae or the numbers that emerged to feed on blossom trusses in spring.
Development of pea bacterial blight caused by Pseudomonas syringae pv. pisi in winter and spring cultivars of combining peas (Pisum sativum) with different sowing dates
Authors: MANSFIELD P J , WILSON D W , HEATH M C , SAUNDERS P J 
Published: February 2008

SummaryPea bacterial blight occurred by natural infection in a field trial on peas in 1995. Disease development in the winter cultivars Rafale, Frilene and Froidure was compared with that in the spring cultivars Baccara, Conquest and Bohatyr, each sown on six dates in October, November, December, mid‐March, late March and April. Disease incidence had reached 100% plants affected in all treatments by mid‐July. Disease severity was greater in winter‐sown (October, November or December) than in spring‐sown peas of each cultivar at each assessment. Significant (P < 0.05) differences in disease severity occurred between cultivars in the winter‐sown plots in May and June and the spring cultivars were affected more severely than the winter cultivars. Comparison of areas under the disease progress curves for both disease incidence and severity also showed that the winter‐sown peas were more affected by disease than spring‐sown peas and that spring cultivars were more severely affected than winter cultivars. Yield was strongly correlated with disease severity. A linear regression model suggested that, for peas sown in October, November or December, a yield loss of 0.5 tha‐1 occurred for each 10% increase in canopy area affected by pea bacterial blight.
Factors determining recovery and reversion in mosaic‐affected African cassava mosaic virus resistant cassava
Authors: GIBSON R W , OTIM‐NAPE G W 
Published: February 2008

SummaryThe severity and persistence of symptoms of mosaic virus disease were monitored during the first six months of two growing seasons in cassava of the African cassava mosaic virus (ACMV)‐resistant cv. TMS 30572 either inoculated by grafting with a mild or severe strain or infected from the planted cutting. Symptomless shoots developed between January and March 1995 in two field trials differing in age by c. 6 months; this recovery occurred during particularly hot weather. Recovery was often only temporary in the plants inoculated with the severe strain and occurred later compared with those inoculated with the mild. In 1996, the weather was cooler and recovery that year was delayed until flowering, c. 7 months after planting, when recovered shoots were often produced from buds in the axils of symptomless leaves produced amongst diseased leaves. Most cuttings taken from the upper parts of diseased plants produced symptomless (reverted) progenies whereas most cuttings taken from the base of diseased plants produced diseased progenies. Reversion seemed to be associated with the recovery that had already occurred in the upper stems of the parent plants.
Determining the relative roles of different aphid species as vectors of cucumber mosaic and bean yellow mosaic viruses in lupins
Authors: BERLANDIER F A , THACKRAY D J , JONES R A C , LATHAM L J , CARTWRIGHT L. 
Published: February 2008

SummaryGlasshouse and field studies were done to determine the relative roles of different colonising and non‐colonising aphid species as vectors of two non‐persistently transmitted viruses, cucumber mosaic cucumovirus (CMV) and bean yellow mosaic potyvirus (BYMV) in narrow‐leafed lupin (Lupinus angustifolius) crops in Australia. The abilities of nine different aphid species in transmitting CMV from infected to healthy lupins and BYMV from infected subterranean clover to healthy lupins were compared in the glasshouse using 5–10 min acquisition access feeds. The percentage transmission efficiencies found with lupin‐colonising aphid species were (CMV/BYMV): Acyrthosiphon kondoi (6/15), Aphis craccivora (10/14) and Myzus persicae (11/77). With non‐colonising species the respective efficiencies were: Brachycaudus rumexicolens (0.9/0), Lipaphis erysimi (4/8), Rhopalosiphum maidis (9/6), R. padi (5/5), Sitobion miscanthi (2/11) and Therioaphis trifolii (4/5). When flying aphids were trapped in the field in four successive years (1993–1996) on vertical nets downwind of virus‐infected lupins, 13 different species were caught at a “wheatbelt” site and 18 at an urban irrigated site. Of 2833 aphids caught at the “wheatbelt” site, 64 transmitted CMV to lupin test plants. At the irrigated site, numbers of aphids transmitting CMV/numbers caught were 12/186 while the corresponding numbers for BYMV were 11/727. M. persicae, A. kondoi and R. padi transmitted both viruses, while additional vectors of CMV found were A. craccivora, Acyrthosiphon pisum, B. rumexicolens, L erysimi, R. insertum, T. trifolii and Toxoptera citricidus. Averaged over four years, A. kondoi accounted for 50% of CMV transmissions at the “wheatbelt” site, M. persicae for 16% and R. padi for 22%, and these three species were caught in the greatest numbers, comprising 28%, 13% and 37% respectively of the total catch. At the irrigated site R. padi accounted for half the CMV transmissions, while R. padi and A. kondoi together accounted for most of the BYMV transmissions. R. padi, A. kondoi, M. persicae and T. citridus were the most common aphid species at this site. These findings suggest that M. persicae, A. kondoi and R. padi are the aphid species likely to be most important as vectors of CMV and BYMV in narrow‐leafed lupins grown in mediterranean‐type climatic zones of southern Australia.
Effect of specific leaf nitrogen content on photosynthesis of sugarcane
Authors: ALLISON J C S , WILLIAMS H T , PAMMENTER N W 
Published: February 2008

SummaryIn the laboratory, rate of photosynthesis (P) of the youngest fully emerged leaf lamina on a shoot, whether taken from a 4 or 8 month old sugarcane plant, increased approximately linearly with specific leaf nitrogen content (SLN) from < 1.0 to c. 1.7 g m‐2; the rate of increase was greater the higher the incident photosynthetically active radiation (PAR) flux density, over the range 80 to 1600 μmol m‐2s‐1. In a field crop receiving standard fertiliser, including 150 kg N ha‐1, SLN of the green leaf canopy decreased more or less linearly with depth, from > 1.7 g m‐2at the top to c. 1.0 g m‐2at the bottom at 15 wk of age, and progressively with time to 1.2 to 0.85 g m‐2from top to bottom of the canopy by week 45. Where an extra 300 N ha‐1were applied in top‐dressings, the decrease in SLN with time was somewhat smaller, to 1.3 to 0.9 g m‐2from top to bottom of the canopy by week 45. Calculations with a model, using the data from laboratory and field, suggest a decrease of about 25% in canopy gross P and about 30% in canopy net P from wk 15 to wk 45 in the crop receiving standard fertiliser only; the calculated decreases where the crop received additional nitrogen were about 17% and 20% respectively. There would seem to be a need for a change in type of cultivar to make profitable use of augmented nitrogen fertiliser.
Observations on feeding and population structure of five New Zealand terrestrial planarians which prey on lumbricid earthworms
Authors: YEATES G W , BOAG B. , JOHNS P M 
Published: February 2008

SummaryThe feeding of five terrestrial planarians found in New Zealand on European lumbricid earthworms was studied. Under laboratory conditions between 60–83% ofArtioposthiaspp. fed in the first 24 h compared with 21–40% ofAustraloplanaspp. The mean percentage weight gain varied from 31% forAustraloplana sanguineavar.albato 113% forArtioposthiasp. 1. Analysis of the weights of the planarian species showed a mean 11‐fold difference betweenAustraloplana sanguineaandArtioposthia triangulataand that these body weights were not related to mean percentage weight gains after feeding. The relationship between the weights of egg capsules and pregnant female planarians was similar forAustraloplana sanguineavar.alba(11%),Artioposthia triangulata(12%) andArtioposthia testacea(13%). This study confirms that there are terrestrial planarians in New Zealand which have the potential to prey upon European lumbricid earthworms but which have not been detected in Europe. Greater knowledge of their biology is necessary to control the spread and impact of these organisms around the world.
Application of the most probable number method to estimations of entomopathogenic nematode populations in soil
Authors: HASS B. , GRIFFIN C T , KEATING J G , DOWNES M J 
Published: February 2008

SummaryThe calculation of most probable numbers (mpn) was used for the estimation of numbers of infective entomopathogenic nematodes in soil. The mpn concept was first introduced in bacteriology as a means of estimating numbers of organisms in a substrate without a direct count, in cases where direct enumeration could not be applied. In the work reported here, soil samples infested with infective juveniles (IJs) ofHeterorhabditis megidis(isolate HF85) were diluted with uninfested soil and the diluted soils were baited with mealworm larvae (Tenebrio molitor). The mpn of infective units of IJs in the undiluted soil was calculated. The mpn calculation was found to be applicable to entomopathogenic nematodes in soil under particular conditions. It could be successfully applied to data for the response of soil units but not to the data based on the response of individual insects, as the latter did not confirm to a Poisson series. The calculated mpn represented between 2.9 and 7.1% of the initial inoculum of IJs. It was suggested that IJs might act as a group in infecting an insect host. Using the data forTenebriomortality on parasitisation, the mpn based on quantal response of the mealworms would therefore not give the true density of IJs in the soil sample but the effective density, or the quantity of infective units. Although the biological significance of the infective unit needs further clarification, mpn was found to be a useful parameter for use in comparative experiments.
Evaluation of groundnut genotypes for heat tolerance1
Authors: CHAUHAN YASHVIR S , SENBOKU T. 
Published: February 2008

SummaryHeat tolerance of groundnut (Arachis hypogaea L.) genotypes was evaluated by solute leakage and chlorophyll fluorescence techniques in heat‐hardened and non‐hardened plants. To determine the appropriate hardening treatment, 1‐month‐old plants of two groundnut genotypes, ICGV 86707 and Chico were conditioned at five combinations of hardening (37°C) and non‐hardening (30°C) air temperatures over a 5‐day period. Heat injury, was assessed through measurements of electrolyte leakage after stressing leaf discs to 55°C for 15 min. The relative injury was significantly influenced by the conditioning temperatures and by the temperature during 24 h prior to measurement if those involved non‐hardening conditions. Relative injury and chlorophyll fluorescence were measured after stressing leaves of six genotypes at a range of temperatures between 49°C and 55°C. Significant genotype × hardening treatment interactions were observed in relative injury and chlorophyll fluorescence. Chico was susceptible to heat stress, the relative injury test identified ICGV 86707 as tolerant, and the chlorophyll fluorescence test identified ICGV 86707 as tolerant under hardened conditions and ICGV 87358 as tolerant when non‐hardened. When expressed as percentage of control values, the relative injury and chlorophyll fluorescence measurements over the 49–53°C stress temperature range were strongly correlated. Chlorophyll concentrations were increased by hardening in all genotypes except Chico. In Chico, chlb concentration was decreased and the chla/b ratio increased by hardening, and chlorophyll concentrations were correlated with chlorophyll fluorescence parameters. Chlorophyll concentration may therefore provide an alternative means of screening for heat tolerance.
Long term water stress inactivates Rubisco in subterranean clover
Authors: MEDRANO H. , PARRY M A J , SOCIAS X. , LAWLOR D W 
Published: February 2008

SummaryIn long‐term field experiments, during consecutive years, microswards of subterranean clover were irrigated to minimise water deficits or subjected to progressively increasing drought over 30 days. Both leaf water potential and relative water content steadily decreased during the experiments. Plants affected by drought grew more slowly and photosynthesis was decreased. Photosynthetic rate (A) and Rubisco were analysed in relation to midday water potentials and relative water contents. The difference in A between draughted and irrigated plants increased progressively, in part as a result of decreased stomatal conductance and CO2 concentration within leaf (Ci). However, A‐Ci curves suggest that the photosynthetic capacity in plants experiencing long‐term stress was reduced by 50% when compared with irrigated plants. Drought decreased both the initial and the total Rubisco activity per unit area in a similar way but did not reduce the amount of Rubisco protein per unit leaf area. Thus, the specific activity of Rubisco, rather than its activation state, decreased suggesting that under water stress the active sites were blocked by inhibitors.
Attachment microbes antagonistic against Botrytis cinerea—biological control and scanning electron microscope studies in vivo
Authors: COOK DARRYL W M , LONG PETER G , GANESH SIVA , CHEAH L‐H 
Published: February 2008

SummaryBacteria and yeasts, selected by an attachment assay for their ability to adhere to Botrytis cinerea hyphae or conidia, were evaluated for biocontrol potential against B. cinerea on excised tomato stems. Eight of the 12 bacteria and seven of the eight yeast isolates conferred 90% to 100% biocontrol activity when antagonist populations were applied at three to 80 times the pathogen inoculum density. Biocontrol was maintained at similar levels when biocontrol agent (BCA) application was delayed up to 48 h after pathogen challenge. Scanning electron microscopy showed extensive colonisation of B. cinerea mycelium or conidia by many of these isolates and also evidence of pathogen degradation.The biocontrol efficacy and potential for the assay are discussed with respect to cell‐to‐cell adhesion as a vehicle to deliver antagonistic mechanisms to highly specific pathogen sites.
The phenology of Lygus rugulipennis, the European tarnished plant bug, on late‐season strawberries, and control with insecticides
Authors: EASTERBROOK M A. 
Published: February 2008

SummaryThe phenology of Lygus rugulipennis, the European tarnished plant bug, was studied in fields of strawberries producing late‐season (July to September) crops. Adults invaded fields in small numbers, mainly in July. Large numbers of nymphs were found in late July and early August; these matured into adults from late August. Adults formed the overwintering population; some remained in strawberry fields but left in spring to feed on other host plants. All the insecticides tested, i.e. malathion, chlorpyrifos, heptenophos, cypermethrin, bifenthrin and trichlorfon, gave good short‐term control of nymphs.
Biological control of the black vine weevil, Otiorhynchus sulcatus (Coleoptera: Curculionidae) with entomopathogenic nematodes (Nematoda: Rhabditida)
Authors: KAKOULI‐DUARTE T. , LABUSCHAGNE L. , HAGUE N G M. 
Published: February 2008

SummaryTrials conducted under glasshouse conditions showed that control of Otiorhynchus sulcatus larvae in strawberry plants can be effective using Steinernema carpocapsae and Heterorhabditis megidis, given that temperature and moisture extremes are avoided. In field experiments, the double line T‐Tape® drip irrigation system performed better than the single line T‐Tape® system, effectively distributing the nematodes along and across strawberry raised beds, and placing them close to the root zone where O. sulcatus larvae feed. As soil temperatures are satisfactory for nematode infectivity from late spring to early autumn, nematode applications were aimed at late instar larvae during spring, and early instar larvae during summer. Late summer field treatment with S. carpocapsae induced 49.5% reduction of the early instar larvae, and field application of the same nematode species in late spring resulted in 65% control of late instar larvae. In the same trial, spring application of H. megidis caused 26% mortality of late instar larvae of O. sulcatus.
The use of chemicals, antagonists, repellents and physical barriers for the control of Lycoriella auripila (Diptera: Sciaridae), a pest of the cultivated mushroom Agaricus bisporus
Authors: WHITE P F. 
Published: February 2008

SummaryThe sciarid, Lycoriella auripila, is a serious pest of commercial mushroom production. A series of trials demonstrated that the use of early, specifically‐targeted, treatments of insecticides and/or antagonists and repellents, which distance treatment time from crop harvest, have the potential to play a useful part in the control of initial and subsequent generations of this pest. Of the treatments examined, those involving a drench treatment of the compost at filling (before pasteurisation) proved to be the most effective. Cyromazine and diflubenzuron were the most active insecticides tested, with cyromazine achieving a superior level of control of the initial infestation. Repellents and antifeedants were also effective, with calcium oxalate and sinapic acid both achieving about 50% control when applied at filling. Treatments applied later during the production cycle, unless in combination with a treatment at filling, were progressively less effective at controlling both the initial sciarid infestation and later generations of larvae. Multiple treatments caused greater reductions in fly populations than did the single treatments and continued to do so throughout the cropping cycle, the greatest reduction in the initial generation (79%) occurring with a triple treatment of cyromazine. With the exception of some diflubenzuron treatments, those that were effective resulted in increases in yield. The use of a physical paper barrier caused significant increases in both fly numbers and total yield.
Black Sigatoka disease of banana: spatial and temporal variability in disease development
Authors: SMITH M C. , RUTTER J. , BURT P J A. , RAMIREZ F. , GONZALEZO E H 
Published: February 2008

SummaryField observations of black Sigatoka disease symptom development were made on banana plants from four sites (30 m apart) within an unsprayed plantation of dimensions 100 m × 200 m in Costa Rica during two field visits: October 1993‐February 1994 (wet to dry season) and April‐September 1995 (dry to wet season). From these observations, estimates of the symptom‐free period and the average rate of symptom development (during the symptomatic phase) were made for each leaf. No significant differences were found between sites in rates of symptom development in either 1993/94 or 1995, or in symptom‐free period for 1993/94 (data were not suitable to test for between‐site differences in symptom‐free period for 1995). This suggests that forecasts would not have to take into account differences in location within this small plantation. Symptom‐free time decreased over the 1995 observation period, was less than in 1993/94 and correlated with increases in hours per day at a relative humidity (r.h.) of 100%. Because plantations may be sprayed many times per year, forecasts have to be sensitive to short‐term changes in disease severity. Seasonal trends in some more rapidly‐and easily‐assessed characters (number of disease‐free leaves, disease scores of specific leaves and average disease scores of entire plants) accurately reflected trends in the more detailed observations of symptom severity, hours per day at 100% r.h. and numbers of leaves unfurling per unit time. This suggests that these could be used as indicators of changes in disease severity in a forecasting scheme.
Studies on population dynamics and spatial distribution of leafhoppers in vineyards (Homoptera: Cicadellidae)
Authors: BOSCO D. , ALMA A. , ARZONE A. 
Published: February 2008

Summary.Thirty‐two species of Cicadellidae, including the Macropsinae, Agalliinae, Penthimiinae, Aphrodinae, Cicadellinae, Typhlocybinae and Deltocephalinae, 10 of which were already known as phytoplasma vectors, were captured in vineyards using yellow sticky traps. Adult population dynamics of the most abundant species of Penthimiinae and Deltocephalinae were studied over the whole growing season. Penthimia nigra was captured in May and June, Anoplotettix fuscovenosus in June‐August, Fieberiella florii in August‐October, Macrosteles sexnotatus in May and October, Scaphoideus titanus in July‐September, Thamnotettix spp. (Th. confinis, Th. dilutior, Th. exemtus, Th. zelleri) in April‐June, while Euscelidius variegatus, Neoaliturus fenestratus, Platymetopius major and Psammotettix spp. (P. alienus, P. confinis) were trapped throughout the growing season. The aggregation level of the above species was investigated by means of Taylor's power law. A. fuscovenosus showed a nearly random distribution in vineyards (0.95 < b < 1.11), while N. fenestratus, P. major and S. titanus were strongly aggregated (1.32 < b < 1.81). The other species showed intermediate levels of aggregation (1.12 > b < 1.32). The results indicate that at least six Deltocephalinae species, A. fuscovenosus, E. variegatus, F. florii, M. sexnotatus, N. fenestratus and S. titanus, known as phytoplasma vectors and commonly found in vineyards, could play a role in Grapevine Yellows (GY) epidemiology. GY transmission trials with these species are needed.