Evaluating sex-pheromone- and kairomone-based lures for attracting codling moth adults in mating disruption versus conventionally managed apple orchards in Pennsylvania

BACKGROUND: Effectiveness of different types of commercial sex‐pheromone‐ and kairomone‐based lures for attracting codling moth adults may vary under different pest management practices. The attractiveness of four types of codling moth (CM) lures (CM L2 Long‐Life^®, CM 10X Megalure^®, Pherocon CM DA^® and Pherocon CM‐DA Combo^®) was evaluated in commercial apple orchards either treated with sex pheromone mating disruption (MD) or only conventional insecticides (non‐MD) in Adams County, Pennsylvania, in 2006 and 2007. RESULTS: CM DA Combo lure was most effective in terms of mean seasonal weekly moth capture as well as mean cumulative moth capture in MD orchards. In both years, the CM L2 lure was as attractive to adult moths as the CM DA Combo lure in non‐MD orchards. The CM DA and CM 10X lures caught significantly fewer moths in both MD and non‐MD orchards compared with the CM DA Combo lure. CONCLUSIONS: ON the basis of mean seasonal weekly moth capture as well as mean cumulative moth capture, the CM DA Combo and CM L2 lures were found to be significantly more effective for monitoring CM adults in both MD and non‐MD orchards. In contrast, the CM DA and CM 10X lures were not as effective in either type of orchard. Copyright © 2011 Society of Chemical Industry     

A new fire ant (Hymenoptera: Formicidae) bait base carrier for moist conditions

BACKGROUND: A new water‐resistant fire ant bait (T‐bait; cypermethrin 0.128%) consisting of dried distillers grains with solubles (DDGS) as a carrier was developed and evaluated against a standard commercial bait (Advion^®; indoxacarb 0.045%) under both laboratory and field conditions. RESULTS: When applying the normal T‐bait or Advion^® in the laboratory, 100% of Solenopsis invicta Buren worker ants were killed within 4 days. However, when the T‐bait and Advion^® were wetted, 70.6 and 39.7% of the ants were killed respectively. Under field conditions, dry T‐bait and dry Advion^® had almost the same efficacy against ant colonies. However, when T‐bait and Advion^® came in contact with water, the former's ability to kill S. invicta colonies in the field was only marginally reduced, while Advion^® lost virtually all of its activity. In addition, DDGS was also shown to be compatible with a number of other insecticides, such as d‐allethrin, permethrin and pyrethrin. CONCLUSION: Based on its properties of remaining attractive to the fire ants when wetted, combined with its ant‐killing abilities both in the laboratory and in the field, T‐bait is an efficient fire ant bait, especially under moist conditions. Copyright © 2010 Society of Chemical Industry     

Investigations on Oecophylla longinoda (Latreille) (Hymenoptera: Formicidae) as a biocontrol agent in the protection of cashew plantations

BACKGROUND: Cashew (Anacardium occidentale L.) has become a very important non‐traditional tree crop in Ghana. The crop is, however, attacked by sap‐sucking insects, particularly the mosquito bug, Helopeltis schoutedeni Reuter, the leaf‐footed bug, Pseudotheraptus devastans (Dist.), and the coreid bug, Anoplocnemis curvipes (F.), which feed on shoots, panicles and fruits. Their damage is characterised by withering of the latter. In Ghana, Oecophylla longinoda Latr. occurs in large numbers on cashew and other native plants, but little is known about its relationship with insect pests. The relationship between O. longinoda and shoot and panicle damage by sap‐sucking bugs and the effectiveness of O. longinoda as a biocontrol agent in the protection of cashew as compared with two chemical insecticides, lambda‐cyhalothrin (Karate^®) and cypermethrin + dimethoate (Cyperdim^®), were therefore investigated at Bole in the northern region of Ghana. RESULTS: There was a negative correlation between numbers of O. longinoda nests and pest damage. Trees treated with cypermethrin + dimethoate (969 mg AI mL^?1 tree^?1) and lambda‐cyhalothrin (100 mg AI mL^?1 tree^?1) recorded the smallest bug numbers, followed by O. longinoda. Trees infested by Oecophylla longinoda and trees treated with cypermethrin + dimethoate and with lambda‐cyhalothrin had less than 6% pest damage to shoots, panicles and fruits, while water‐sprayed trees recorded damage as high as 36.8% (shoots) in February, 32.9% (panicles) in February and 37.8% (fruits) in March. Cypermethrin + dimethoate again recorded the highest (485.0 kg ha^?1) nut yield, followed by O. longinoda (431.0 kg ha^?1), with water recording the lowest (93.0 kg ha^?1) nut yield. CONCLUSION: The results indicate that O. longinoda can be used to control some sucking bugs as effectively as some insecticides. Copyright © 2008 Society of Chemical Industry     

Larvicidal activity of Cnidium monnieri fruit coumarins and structurally related compounds against insecticide-susceptible and insecticide-resistant Culex pipiens pallens and Aedes aegypti

BACKGROUND: An assessment was made of the toxicity of imperatorin and osthole identified in Cnidium monnieri fruit, 11 related compounds and five insecticides to larvae from insecticide‐susceptible Culex pipiens pallens (KS‐CP strain) and Aedes aegypti and wild C.p. pallens (YS‐CP colony) using a direct‐contact mortality bioassay. Results were compared with those of the conventional larvicide temephos. RESULTS: Imperatorin (LC₅₀ = 3.14 and 2.88 mg L^?1) was 1.9‐, 3.7‐ and 4.2‐fold and 2.4‐, 4.5‐ and 4.6‐fold more toxic than isopimpinellin, isoimperatorin and osthole against susceptible C. p. pallens and A. aegypti larvae respectively. Overall, all of the compounds were less toxic than temephos (0.011 and 0.019 mg L^?1). The toxicity of these compounds was virtually identical against larvae from the two Culex strains, even though YS‐CP larvae were resistant to fenthion (resistance ratio RR = 390), deltamethrin (RR = 164), cyfluthrin (RR = 14) and temephos (RR = 14). This finding indicates that the coumarins and the insecticides do not share a common mode of action. The structure–activity relationship indicates that the chemical structure and alkoxy substitution and length of the alkoxyl side chain at the C8 position are essential for imparting toxicity. CONCLUSION: The C. monnieri fruit‐derived coumarins and the related coumarins described merit further study as potential insecticides or lead molecules for the control of insecticide‐resistant mosquito populations. Copyright © 2012 Society of Chemical Industry     

Evaluation of herbicides against Phalaris minor in wheat in north-western Indian plains

Phalaris minor, the most serious weed in wheat in north‐western India, has developed extensive isoproturon resistance due to continuous isoproturon use. For its control, alternative herbicides (flufenacet, metribuzin and sulfosulfuron) at different application rates and timing were evaluated in wheat. In addition, herbicide carryover risk onto rotational crops (sorghum; maize and green gram, Vigina radiata) was also assessed. Isoproturon at 1 and 2 kg a.i. ha^?1 provided only 10.5% and 51.8%P. minor control respectively. Of the other herbicides, early post‐emergent [15–21 days after sowing (DAS)] flufenacet at 180–480 g a.i. ha^?1 provided acceptable control of P. minor, but failed to control broad‐leaved weeds and was phytotoxic to the wheat crop. Metribuzin at 210 g a.i. ha^?1 was effective in controlling both Phalaris and dicotyledonous weeds. Mixtures of both flufenacet and metribuzin at reduced rates were better than flufenacet for weed control and grain yield. The efficacy of flufenacet and metribuzin was drastically reduced with later growth stages of P. minor (four to five leaf). Whereas sulfosulfuron at 25–30 g a.i. ha^?1, applied either early post‐emergence (19 DAS) or post‐emergence (30–42 DAS), was quite effective. Overall, sulfosulfuron was the most effective treatment with regard to weed control and crop yield. However, maize and sorghum grown in rotation after harvest of sulfosulfuron‐treated wheat plots showed 65–73% crop biomass inhibition. The residual effect of sulfosulfuron was also noticed on Trianthema portulacastrum (Horse purslane), causing 73.5% dry matter reduction. By contrast, no carryover damage with flufenacet was observed on maize, sorghum and green gram. Glasshouse pot experiments and field trials investigating crop sensitivity to pre‐plant applications of sulfosulfuron found the decreasing order: sorghum > maize > green gram. The risk of carryover onto rotational crops should be considered when choosing alternative herbicides for P. minor control in wheat.     

Testing insecticide resistance management strategies: mosaic versus rotations

BACKGROUND: Developing scientifically valid, economically acceptable insecticide resistance management (IRM) programs is critical for sustainable insect management. The diamondback moth, Plutella xylostella (L.), has demonstrated an ability to develop resistance to many different classes of insecticides, including proteins produced by the bacterium Bacillus thuringiensis Berliner (Bt). Recently it has developed resistance to the novel compounds spinosad and indoxacarb. In greenhouse cage experiments, a laboratory‐selected population of P. xylostella resistant to spinosad, indoxacarb and Bt was used to compare population growth and resistance evolution if these three insecticides were rotated or used in a mosaic fashion. RESULTS: The average population density through nine generations was lowest in the treatment in which the insecticide was rotated every generation (R‐1) (x? = 20.7 ± 3.20) compared with the treatment in which the insecticide was rotated every third generation (R‐3) (x? = 41.4 ± 17.6) or where the insecticides were applied as a mosaic (M) (x? = 41.8 ± 6.53). After nine generations, the survival of resistant individuals increased for each insecticide (7.2–73.5%) compared with the population without selection (CK) (0.73–3.1%). Survival on spinosad was significantly lower (23.7%) in the single‐generation rotation than for the other two treatments, both of which exceeded 72%. The calculated survival on all three insecticides treated simultaneously, according to the survival on each insecticide, was 0.26, 0.81 and 1.6% for R‐1, R‐3 and M treatments respectively. CONCLUSION: Results of both population density and resistance development indicated that insecticide rotation every generation was better for IRM than if the insecticide was rotated every third generation or if the three insecticides were applied as a mosaic. Copyright © 2010 Society of Chemical Industry     

Toxicological and biochemical response to azinphos-methyl in Cydia pomonella L. (Lepidoptera: Tortricidae) among orchards from the Argentinian Patagonia

BACKGROUND: Azinphos‐methyl is the main insecticide used to control codling moth on apple and pears in Northern Patagonia. The aim of this study was to evaluate the toxicological and biochemical response of diapausing larvae of codling moth in orchards subjected to different insecticide selection pressure. RESULTS: Dose–mortality assays with azinphos‐methyl in diapausing larvae of Cydia pomonella L. showed significant differences between the LD₉₅ from a population collected in one untreated orchard (2.52 µg moth^?1) compared with that in a laboratory‐susceptible population (0.33 µg moth^?1). Toxicity to azinphos‐methyl in field populations of diapausing larvae collected during 2003–2005 was evaluated by topical application of a discriminating dose (2.5 µg moth^?1) that was obtained from larvae collected in the untreated orchard (field reference strain). Significantly lower mortality (37.71–84.21%) was observed in three out of eight field populations compared with that in the field reference strain. Most of the field populations showed higher esterase activity than that determined in both the laboratory susceptible and the field reference strains. Moreover, there was a high association between esterase activity and mortality (R² = 0.64) among the field populations. On the other hand, a poor correlation was observed between glutathione S‐transferase activity and mortality (R² = 0.33) among larvae collected from different orchards. CONCLUSIONS: All the field populations evaluated exhibited some degree of azinphos‐methyl tolerance in relation to the laboratory susceptible strain. Biochemical results demonstrated that esterases are at least one of the principal mechanisms involved in tolerance to this insecticide. Copyright © 2008 Society of Chemical Industry     

Comparison of pheromone lures used in mass trapping to control the tomato leafminer Tuta absoluta (Meyrick, 1917) in industrial tomato crops in Kairouan (Tunisia)

An experimental trial of integrated pest management against Tuta absoluta (Meyrick) based on mass trapping with a density of 32 traps per hectare was conducted in a 5 ha open‐field tomato crop. During this trial, the efficiency of three brands of sex pheromone dispenser commercialized in Tunisia was tested. The ‘superdosed’ pheromone lure type TUA‐Optima^® (Russell IPM, Deeside, Flintshire, CH5 2LA, United Kingdom) loaded with 0.8 mg of synthetic pheromone was more attractive to males of T. absoluta, and these lures should be used with high populations. Standard lures Pherodis^® and TUA‐500^® containing 0.5 mg of pheromone were less attractive, and can be used in open‐field tomato crops with lower populations of T. absoluta. An assessment of the susceptibility of crop borders to T. absoluta, based on data collected from traps, revealed that levels of adult T. absoluta were similar between borders with either tomato or cereal crops. Particular attention should thus be paid to crop borders even when not adjacent to other tomato crops.     

Beet armyworm (Spodoptera exigua) resistance to spinosad

Susceptibility to spinosad (Success®/Tracer®) of beet armyworm (Spodoptera exigua) from the southern USA and Southeast Asia was determined through exposure of second‐ and third‐instar larvae to dipped cotton leaves. LC₅₀ estimates of susceptibility of second‐ and third‐instar larvae of field populations ranged from 0.279 to 6.14 and 0.589 to 14.0 mg spinosad litre⁻¹, respectively. A Thailand population was 22‐ and 24‐fold less susceptible than the six other US field populations evaluated, and 85‐ and 58‐fold less susceptible than a reference laboratory population, respectively. From these results, we initiated experiments to test the hypothesis that the Thailand population was resistant to spinosad. F₁ crosses between the resistant Thailand population and a susceptible reference strain yielded individuals that were 22‐fold less sensitive to spinosad than the susceptible parent. This same resistant strain exhibited significantly greater survivorship on plants treated with spinosad in the field. Lastly, selection of an Arizona population resulted in a significant reduction in susceptibility to spinosad, further substantiating the hypothesis of a genetic basis for resistance to spinosad. These findings indicate a vulnerability of this new insecticide to resistance development in beet armyworm and should serve as a warning against excessive use of it. © 2000 Society of Chemical Industry     

Developmental studies of transgenic maize expressing Cry1Ab on the African stem borer, Busseola fusca; effects on midgut cellular structure

BACKGROUND: Busseola fusca is a major pest of maize in Africa but unfortunately is difficult to control using chemical insecticides. Insect‐resistant transgenic crops may provide an alternative viable strategy to control this pest. RESULTS: Recombinant Cry1Ab (1%) reduced larval weight by 60% over the trial period, while larval weight in the control group increased by 25%; no effects on mortality were observed. Insect survival, developmental rate and pupal and adult weight were significantly reduced (P < 0.05) on maize expressing Cry1Ab (MON810) compared with the non‐transformed parental line. These differences were more pronounced with second‐instar larvae than with third‐instar larvae. Leaf area consumed by Bacillus thuringiensis (Bt)‐fed larvae was significantly lower (0.5 cm² larva^?1 day^?1) compared with the area consumed by control‐fed insects (3.3 cm² larva^?1 day^?1). EM studies revealed that consumption of Bt maize deleteriously affected gut integrity. Effects were observed in columnar cells of the midgut epithelium, with the cytoplasm becoming highly vacuolated; the microvilli were disorganised, the mitochondria were abnormal and there was an increase in the number of lysosomal bodies. The rough endoplasmic reticulum had also become dilated. CONCLUSION: This study confirms the potential for Bt maize, when used as part of an IPM programme, for control of B. fusca. Copyright © 2011 Society of Chemical Industry     

Laboratory assays of select candidate insecticides for control of Dendroctonus ponderosae

BACKGROUND: The mountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae, Scolytinae), is the most destructive bark beetle in western North America. Dendroctonus ponderosae can be prevented from successfully colonizing and killing individual trees by ground‐based sprays of insecticides applied directly to the tree bole. However, the future availability of several active ingredients, including carbaryl which is most commonly used in the western United States, is uncertain. Two novel insecticides, cyantraniliprole [Cyazypyr^?‐OD (oil dispersion) and Cyazypyr^?‐SC (suspension concentrate)] and chlorantraniliprole (Rynaxypyr^®), and carbaryl were assayed in both filter paper and topical assays. RESULTS: Compared with 20 000 mg L^?1 carbaryl (i.e. the maximum label rate for solutions applied to conifers for protection from bark beetle attack in the western United States), cyantraniliprole OD caused similar rates of mortality in D. ponderosae adults at 400‐fold weaker concentrations in both bioassays, while cyantraniliprole SC caused similar rates of mortality at 40‐fold weaker concentrations. Probit analyses confirmed that D. ponderosae is most sensitive to cyantraniliprole OD, while chlorantraniliprole was effective at concentrations similar to carbaryl. CONCLUSIONS: These results suggest that lower concentrations of carbaryl have merit for field testing than have been previously considered. While cyantraniliprole and chlorantraniliprole have similar modes of action, cyantraniliprole OD appears to have greater promise for protecting individual trees from mortality attributed to D. ponderosae attack and should be evaluated in field studies. Published 2011 by John Wiley & Sons, Ltd.     

A review of research to address carrot fly (Psila rosae) control in the UK1

Carrot fly (Psila rosae) is a serious pest of umbelliferous crops such as carrot, parsnip, celery and parsley. Carrot fly has been studied in the UK for more than 60 years. Whilst some of these studies have been focused on insecticides, others have demonstrated the potential for non‐insecticidal methods of control that might contribute to an integrated pest management strategy. These include rotation and spatial separation of susceptible crops; carrot varieties with partial resistance to carrot fly; and crop management strategies to avoid oviposition or the development of severe damage. This paper outlines some of the approaches that have been taken and indicates how these are, or might be, used in practice.     

Laboratory and field comparisons of insecticides to reduce infestation of Drosophila suzukii in berry crops

BACKGROUND: The spotted wing Drosophila, Drosophila suzukii (Matsumura, 1931) (Diptera: Drosophilidae), is an invasive pest of small‐fruit crops. Unlike most other Drosophila, this insect is able to oviposit into and damage ripe and ripening fruit, making it unmarketable. Because this is a new pest in the United States, it is necessary to identify registered insecticides to manage this insect effectively in conventional and organic production systems. RESULTS: The present laboratory bioassays and field trials identified a number of insecticides representing various modes of action that are effective in controlling D. suzukii. Products that performed well in the laboratory bioassay also performed well in the field, indicating that screening of new chemistries in the laboratory is a worthy exercise. Field application of pyrethoids, organophosphates or spinosyns provided 5–14 days of residual control of D. suzukii. The efficacy of the neonicotinoids as adulticides was not satisfactory compared with the other contact‐mode‐of‐action chemistries. Based on the zero tolerance by the small‐fruit industry and the individual effects mentioned above, neonicotinoids are not currently recommended for D. suzukii management. CONCLUSIONS: There are effective insecticides registered for controlling D. suzukii infestations in susceptible small‐fruit crops. Copyright © 2011 Society of Chemical Industry     

Interactions between the tillage system and crop rotation on the crop yield and weed populations under arid conditions

Field experiments were conducted in Iran in order to determine the interactions between the tillage system and crop rotation on weed seedling populations and crop yields from 2002 to 2005. No tillage, shallow tillage and deep tillage were the main plots and three crop sequences comprising continuous wheat (W‐W), wheat–canola–wheat–canola (C‐W) and wheat–safflower–wheat–safflower (S‐W) were the subplots. Bromus japonicus, Carthumus lanatus, Polygonum aviculare, Lolium temulentum and Avena ludoviciana were found to be the dominant species. The initial weed population in 2002 was estimated at 65 seedlings per m² and B. japonicus (～35 seedlings per m²) was the most abundant species, followed by A. ludoviciana and L. temulentum. The dominant weed species mostly did not favor the combination of S‐W and C‐W with any tillage type. For the B. japonicus population, S‐W in combination with moldboard plowing indicated the lowest seedling population. In conclusion, the crop sequence in combination with tillage would help to control troublesome weed species. Safflower and canola were determined to be effective in reducing the grass weeds. The inclusion of these crops in rotation also increased the total revenue of the cropping systems because of the higher sale price of canola and safflower.     

Neurophysiological studies of the effects of permethrin upon pyrethroid resistant (kdr) and susceptible strains of dipteran larvae

Permethrin at concentrations as high as 10^?6 had no detectable effect upon neuromuscular transmission at 20-21°C in the body-wall muscles of susceptible larvae of Lucilia sericata and susceptible and resistant (kdr) strains of larvae of Musca domestica. At the higher concentrations of 5 × 10^?6M, muscle cells in all strains and species of larva were slowly depolarised, resulting in failure of neuromuscular transmission when the level of depolarisation corresponded with the peak height of the postsynaptic potentials. Multiple postsynaptic potentials were sometimes obtained in response to a single electrical stimulus to the motor axon. Neither of these effects is considered to result from interference with release of the neurotransmitter or its binding to the postsynaptic receptors. Spontaneous activity in sensory nerve fibres from susceptible larvae was increased followed by intermittent bursting and block at concentrations of permethrin as low as 10^?9M at 20-21°C and 10^?10 at 26°C. Resistant larvae of M. domestica were 1000 times less sensitive, needing concentrations of permethrin as high as 10^?6M at 20-21°C and 10^?7M at 26°C to affect sensory discharge. The results are discussed in relationship to the cause of knockdown by pyrethroid insecticides and to possible changes in the nervous system which may be brought about by the kdr resistance factor.     

Aminopyralid soil residues affect rotational vegetable crops in Florida

BACKGROUND: Bahiagrass (Paspalum notatum Flueggé) is a poor host of several soilborne pests of vegetable crops; therefore vegetable crops are commonly grown in a rotation with bahiagrass pastures in Florida. The herbicide aminopyralid provides foliar and soil residual weed control and increases forage production in bahiagrass pastures; however, the soil residual activity of aminopyralid makes carryover injury likely in subsequent sensitive vegetable crops. Field research was conducted to determine the sensitivity of five vegetable crops to soil residues of aminopyralid. RESULTS: At an aminopyralid soil concentration of 0.2 µg kg^?1 (the limit of quantitation for aminopyralid in this research), crop injury ratings were 48% (bell pepper), 67% (eggplant), 71% (tomato), 3% (muskmelon) and 3% (watermelon), and fruit yield losses (relative to the untreated control) at that concentration were 61, 64, 95, 8 and 14% in those respective crops. CONCLUSIONS: The crops included in this research were negatively affected by aminopyralid at soil concentrations less than the limit of quantitation (0.2 µg kg^?1). Therefore, it was concluded that a field bioassay must be used to determine whether carryover injury will occur when these crops are planted on a site where aminopyralid has been previously applied. Copyright © 2011 Society of Chemical Industry     

Evaluation of semiochemical toxicity to houseflies and stable flies (Diptera: Muscidae)

BACKGROUND: The housefly, Musca domestica L., and stable fly, Stomoxys calcitrans (L.) are cosmopolitan pests of both farm and home environments. Houseflies have been shown to be resistant to a variety of insecticides, and new chemistries are slow to emerge on the market. Toxicities of selected semiochemicals with molecular structures indicative of insecticidal activity were determined against adults from an insecticide‐susceptible laboratory strain of houseflies. The three most active semiochemicals were also evaluated against recently colonized housefly and stable fly strains. RESULTS: Nineteen semiochemicals classified as aliphatic alcohols, terpenoids, ketones and carboxylic esters showed toxicity to houseflies and stable flies. Rosalva (LC₅₀ = 25.98 µg cm^?2) followed by geranyl acetone and citronellol (LC₅₀ = 49.97 and 50.02 µg cm^?2) were identified as the most toxic compounds to houseflies. Permethrin was up to 144‐fold more toxic than rosalva on the susceptible strain. However, it was only 35‐fold more toxic to the insecticide‐tolerant field strain. The compounds generated high toxicity to stable flies, with LC₅₀ values ranging from 16.30 to 40.41 µg cm^?2. CONCLUSION: Quantification of LC₅₀ values of rosalva, citronellol and geranyl acetone against susceptible housefly and field‐collected housefly and stable fly strains showed that semiochemicals could serve as potent insecticides for fly control programs. Copyright © 2010 Society of Chemical Industry     

Dose-response relationships for the antifeedant effects of Humulus lupulus extracts against larvae and adults of the Colorado potato beetle

BACKGROUND: Dose–response relationships for antifeedant effects of H. lupulus extracts against larvae and adults of the Colorado potato beetle (CPB) were determined in laboratory conditions. The larval and adult beetles were fed on potato leaflets treated with H. lupulus extract ranging from 0.4 to 40 mg mL^?1 in a no‐choice situation. Their feeding behavior was recorded, and larval growth and antifeedant indexes were calculated. RESULTS: H. lupulus treatments significantly affected larval growth rate, and at higher concentrations the larval weights were significantly reduced over the course of the assay. Adults of CPB were more sensitive to the extracts than the larvae, and, even at lower doses, adult beetles were arrested for longer periods than larvae. CONCLUSION: These results indicate that H. lupulus extracts may have potential for control of CPB, particularly in organic farms where conventional insecticides are not available. Copyright © 2012 Society of Chemical Industry     

Mutations in the sodium channel associated with pyrethroid resistance in the greenhouse whitefly, Trialeurodes vaporariorum

BACKGROUND: Trialeurodes vaporariorum Westwood is an important pest of protected crops in temperate regions of the world. Resistance to pyrethroid insecticides is long established in this species, but the molecular basis of the mechanism(s) responsible has not previously been disclosed. RESULTS: Mortality rates of three European strains of T. vaporariorum to the pyrethroid bifenthrin were calculated, and each possessed significant resistance (up to 662‐fold) when compared with a susceptible reference strain. Direct sequencing revealed three amino acid substitutions in the para‐type voltage‐gated sodium channel (the pyrethroid and DDT target site) of bifenthrin‐resistant T. vaporariorum at positions previously implicated with pyrethroid or DDT resistance (M918L, L925I and T929I) in other related species. CONCLUSION: This study indicates that resistance to bifenthrin in T. vaporariorum is associated with target‐site insensitivity, and that the specific mutations in the sodium channel causing resistance may differ between localities. Copyright © 2012 Society of Chemical Industry     

Biological control of botrytis bunch rot in organic wine grapes with the yeast antagonist Candida sake CPA‐1

The aim of this research was to confirm the efficacy of the yeast antagonist Candida sake CPA‐1 in suppressing botrytis bunch rot development, in an organic vineyard under Mediterranean conditions for two seasons, and compare its performance with that of two biologically based products currently registered for botrytis bunch rot control in New Zealand. In 2009, treatments applied were: commercial formulations of Ulocladium oudemansii (BOTRY‐Zen^®) and chitosan (ARMOUR‐Zen^®), C. sake CPA‐1 combined with the fatty acid‐based additive Fungicover^® and combinations of these products. All treatments were applied six times between early flowering and harvest and compared with an unsprayed control. In 2010, the treatments focused on C. sake and Fungicover and the number of applications was reduced from six to four. The population dynamics of U. oudemansii and C. sake were measured and wine quality tests were carried out in both seasons. Disease control achieved by C. sake treatments in 2009 were comparable to those achieved by BOTRY‐Zen and ARMOUR‐Zen. Applications of C. sake plus Fungicover between flowering and harvest significantly (P < 0·05) reduced botrytis bunch rot incidence and severity by 64% and 90%, respectively, compared with the untreated control in 2009, and by 67% and 89%, respectively, in 2010. Treatments did not adversely affect wine quality parameters after treated grapes were processed. Candida sake consistently provided effective control of botrytis bunch rot in grapes under different meteorological and disease pressure conditions, thereby improving its potential for future commercial applications.