Metabolic mechanisms of indoxacarb resistance in field populations of Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae).

Synergism and metabolic studies were conducted to identify the resistance mechanism against indoxacarb in two Choristoneura rosaceana (Harris) field populations compared to a susceptible population. The synergism study was carried out using diet incorporation bioassay for indoxacarb and the three synergists PBO, DEM, and DEF. The metabolic study consists of indoxacarb in vitro reaction with fifth instar larvae 12,000 g midgut supernatant or with pre-inhibited (in vivo by the esterases inhibitor DEF) fifth instar larvae 12,000 g midgut supernatant at different incubation times. In both susceptible and cherry populations, only DEF significantly synergized indoxacarb with a synergism ratio (SR) of 6.5 and 22.6-fold respectively indicating an involvement of esterases in the both populations. In the apple population, all synergists PBO, DEM, and DEF significantly synergized indoxacarb with SR of 9.6, 7.7, and 285.6-fold respectively indicating a complex resistance case with the possible involvement of all three metabolic resistance mechanisms with the central role of esterase enzymes. In vitro, the indoxacarb (DPX-JW062) was very rapidly metabolized within 5 min into small molecules in the lower portion of the metabolic pathway when it reacted with the midgut supernatant of each population. None of the metabolites in the upper portion of the metabolic pathway were detected at any incubation time including the potent sodium channel blocker DCJW metabolite. The two field populations showed significantly higher rates of metabolism of DPX-JW062 compared to the susceptible population at five min of incubation and that may explain the presence of indoxacarb resistance. In the second part of the in vitro study, the bio-transformation of DPX-JW062 was remarkably decreased when it reacted with the pre-inhibited (by DEF) midgut supernatant of each population. Additionally, the degradation of metabolites in the upper portion of the metabolic pathway remarkably decreased, which resulted in accumulation of DCJW and MP819 metabolites. The accumulation of DCJW metabolite under the pre-inhibited midgut supernatants treatment provided a persuasive explanation of the synergistic impact of esterase inhibitor DEF on indoxacarb in C. rosaceana.

Seasonal and Cross-Seasonal Timing of Fungicide Trunk Injections in Apple Trees to Optimize Management of Apple Scab.

To optimize the number and timing of trunk injections for season-long control of apple scab (Venturia inaequalis), we evaluated 1 to 2 and 4 seasonal and cross-seasonal injections of potassium phosphites and synthetic fungicides and quantified residues in leaves and fruit. Phosphites accumulated in the canopy at the highest concentrations, aligned well in time with scab suppression, and gave better leaf scab control of 41.8 to 73.5% than propiconazole (16.9 to 51.5%) or cyprodinil + difenoconazole (5.4 to 17.4%). More injections of phosphites controlled leaf scab better than fewer (23.7% versus 48.2%), and more fungicide injections resulted in 21.9 to 51.1% better leaf scab control than fewer. Leaf scab control with phosphites was only 3.2 to 13.9% better with 4 cross-seasonal compared with 4 seasonal injections, while 1 to 2 seasonal compared with 1 to 2 cross-seasonal injections improved scab control only for 4.2 to 22.1%. On shoots, injected phosphites provided comparable or for 4.4 to 10.5% and 22.3 to 41.4% better scab control than spray standards. On fruit, injected phosphites slightly improved control compared with sprayed phosphites or the sprayed fungicide standard (33.4 to 40.8%). Two seasonal injections of phosphites controlled shoot scab 5.7% better than 9 spray applications. Five sprays of cyprodinil + difenoconazole controlled scab better than their injections. Fruit residues of phosphites reached 2.8 ppm and declined in all treatments except in 2 seasonal injections and phosphite sprays. Cyprodinil and difenoconazole fruit residues reached 0.02 and 0.07 ppm and declined sharply toward the end of the season. These were far below the United States, Codex, and EU MRL-s of 1, 0.8, and 0.5 ppm for difenoconazole, and 1.7, 2, and 1 ppm for cyprodinil, respectively.

Trunk injection to control Xylosandrus germanus (Coleoptera: Curculionidae) in topworked apple trees.

Xylosandrus germanus (Blandford) is an invasive species of ambrosia beetle known to attack apple trees in North America. Xylosandrus germanus are attracted to ethanol produced by stressed and injured trees and can be a serious problem when grafting a new cultivar onto established fruit trees (topworking). The objective of this study was to evaluate the efficacy of 2 insecticides (emamectin benzoate and azadirachtin) and injection timing (fall and spring) on their ability to control X. germanus colonization in apple trees with simulated topworking. Our study shows evidence that both emamectin benzoate and azadirachtin injections can reduce X. germanus infestations; however, our results were inconsistent. The timing of injections influenced X. germanus, with spring injected azadirachtin being more effective than fall injections. Residue analyses of emamectin benzoate and azadirachtin showed the presence of residues in woody tissue comparable to those found in leaves.

Characterization of the inheritance of field-evolved resistance to diamides in the fall armyworm (Spodoptera frugiperda) (Lepidoptera: Noctuidae) population from Puerto Rico.

The fall armyworm (Spodoptera frugiperda) is one of the most destructive pests of corn. New infestations have been reported in the East Hemisphere, reaching India, China, Malaysia, and Australia, causing severe destruction to corn and other crops. In Puerto Rico, practical resistance to different mode of action compounds has been reported in cornfields. In this study, we characterized the inheritance of resistance to chlorantraniliprole and flubendiamide and identified the possible cross-resistance to cyantraniliprole and cyclaniliprole. The Puerto Rican (PR) strain showed high levels of resistance to flubendiamide (RR50 = 2,762-fold) and chlorantraniliprole (RR50 = 96-fold). The inheritance of resistance showed an autosomal inheritance for chlorantraniliprole and an X-linked inheritance for flubendiamide. The trend of the dominance of resistance demonstrated an incompletely recessive trait for H1 (♂ SUS × â™€ PR) × and an incompletely dominant trait for H2 (♀ SUS × â™‚ PR) × for flubendiamide and chlorantraniliprole. The PR strain showed no significant presence of detoxification enzymes (using synergists: PBO, DEF, DEM, and VER) to chlorantraniliprole; however, for flubendiamide the SR = 2.7 (DEM), SR = 3.2 (DEF) and SR = 7.6 (VER) indicated the role of esterases, glutathione S- transferases and ABC transporters in the metabolism of flubendiamide. The PR strain showed high and low cross-resistance to cyantraniliprole (74-fold) and cyclaniliprole (11-fold), respectively. Incomplete recessiveness might lead to the survival of heterozygous individuals when the decay of diamide residue occurs in plant tissues. These results highlight the importance of adopting diverse pest management strategies, including insecticide rotating to manage FAW populations in Puerto Rico and other continents.

Rainfastness of insecticides used to control Japanese beetle in blueberries.

Field-based bioassays were used to determine the relative impact of rainfall on the relative toxicity of four insecticides, phosmet, carbaryl, zeta-cypermethrin, or imidacloprid, from different chemical classes on adult Japanese beetles, Popillia japonica Newman, in highbush blueberries, Vaccinium corymbosum L. Bioassays were set up 24 h after spraying occurred and Japanese beetle condition was scored as alive, knockdown or immobile 1, 24, and 48 h after bioassay setup. All insecticides were significantly more toxic than the untreated control and zeta-cypermethrin consistently had the greatest toxic effect against the Japanese beetles. All insecticides experienced a decrease in efficacy after simulated rainfall onto treated blueberry shoots, although the efficacy of zeta-cypermethrin was the least affected by rainfall. This study will help blueberry growers make informed decisions on when reapplications of insecticides are needed in the field with the aim of improving integrated pest management (IPM).

Trunk injection delivery of dsRNA for RNAi-based pest control in apple trees.

BACKGROUND: RNA interference (RNAi) is a promising new approach for controlling insect pests without the use of synthetic pesticides. Trunk injection is a delivery system for woody plants that harnesses the vascular system of the tree to transport materials to the tree canopy. Full size apple trees were injected with double-stranded RNA (dsRNA), and season-long leaf samples were taken to measure the vascular mobility and temporal persistence of dsRNA, using quantitative reverse transcription polymerase chain reaction (qRT-PCR). RESULTS: The qRT-PCR results revealed that the quantities of dsRNA in the apple leaves of treated trees were significantly greater than those in the leaves of untreated trees for both 2019 and 2020 studies. The peak dsRNA concentration in 2019 was 242 pg/30 mg of leaf tissue, and in 2020 was 16.4 pg/30 mg. The persistence of dsRNA in the apple tree canopy in 2019 was at least 84 days, and in 2020 was at least 141 days. CONCLUSIONS: The highest mean measurement of dsRNA on a single date in 2019 was 242 pg, which is approximately equivalent to 8 ng/1 g leaf tissue. The projection using the highest replicate concentration from the same date is approximately equivalent to 27 ng/1 g leaf tissue, which may be sufficient to be considered biologically active. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Rainfastness and residual activity of insecticides to control Japanese beetle (Coleoptera: scarabaeidae) in Grapes.

Field-based bioassays and residue profile analysis were used to determine the relative toxicity, rainfastness, and field degradation over time of five insecticides from five insecticide classes on adult Japanese beetles, Popillia japonica Newman (Coleoptera: Scarabaeidae), in grapes, Vitis labrusca L. Bioassays assessed Japanese beetle condition as alive, knockdown, or immobile when exposed for 24 h or 7-d field-aged residues of phosmet, carbaryl, bifenthrin, thiamethoxam, or indoxacarb after 0, 12.7, or 25.4 mm of rain had been simulated. We found that the two most toxic insecticides to Japanese beetle were phosmet and carbaryl, followed by bifenthrin, thiamethoxam, and then indoxacarb. The efficacy of phosmet decreased because of rainfall, but not because of field aging. The efficacy of carbaryl decreased because of rainfall and field aging. The efficacies of bifenthrin and thiamethoxam were not affected by rainfall but decreased because of field aging. The efficacy of indoxacarb was not affected by rainfall or field aging. This study will help vineyard managers make informed decisions on when reapplications of insecticides are needed with the aim of improving integrated pest management programs.

Novaluron causes reduced egg hatch after treating adult codling moths, Cydia pomenella: support for transovarial transfer.

The codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), is a primary pest of apples throughout the United States. Reliance on broad spectrum organophosphates has been declining with the slated cancellation and has shifted towards narrow spectrum insecticides. Novaluron, a chitin synthesis inhibitor, has primarily been used for its ovicidal and larvacidal activities. However, recent studies have demonstrated a transovarial effect after exposure to adults. The effects of novaluron were studied to determine if reduced egg hatch occurs after exposure of different sexes to this compound. Effects of this compound through horizontal transfer were also compared with a topical application to C. pomonella eggs. Results from independent exposure of different sexes to novaluron were different than the control for all three exposure types; male only, female only, and both treated. The horizontal transfer experiment yielded no significant difference while the topical application of novaluron on eggs showed significantly lower egg hatch. Although novaluron has no direct toxicity to adults, the results of this study demonstrate that the delayed lethal activity of this compound reduces hatching of eggs laid by treated adults. Along with the direct ovicidal and larvicidal properties of novaluron, the delayed lethal activity provides an important contribution to the overall control seen in the field.

Resistance Affects the Field Performance of Insecticides Used for Control of Choristoneura rosaceana in Michigan Apples and Cherries.

Field-based residual bioassays and residue analysis were conducted to assess the field performance and toxicity longevity of different insecticides that had previously been associated with resistance of Choristoneura rosaceana populations collected from apple and cherry orchards. In this study, 12-24 h-old larvae of apple and cherry populations were exposed to apple and cherry leaf samples, respectively, at post-application intervals and a susceptible population served as a reference of each. In the apple and cherry trials, the order of residual longevity of insecticides that effectively controlled the tested populations was as follows: bifenthrin and spinetoram (apple: 14, cherry 21-day post-application), phosmet (apple: 7, cherry 14-day post-application), chlorantraniliprole (apple: 7-day post-application), and indoxacarb and emamectin benzoate (apple: 1, cherry 7-day post-application). Compared to the susceptible population, the resistant populations resulted in a measurable loss of field performance, or "practical resistance", for the insecticides emamectin benzoate (at 7-day post-application), chlorantraniliprole (at 21-day post-application), and indoxacarb (at all post-application intervals) in the apple trials, while in cherry trial just indoxacarb at 7-day post-application showed a reduced efficacy. In terms of long-lasting residues, only chlorantraniliprole and indoxacarb maintained measurable leaf residues over all post-application intervals while the leaf residues of the other compounds had largely degraded within the first 7 days. These findings can help fruit growers make adjustments to their spray/re-application intervals and optimally utilize important chemical tools in their integrated pest management programs.

Efficacy of intermittent exposure to bright light for treating maladaptation to night work on a counterclockwise shift work rotation.

OBJECTIVES: Rotating shift work is associated with adverse outcomes due to circadian misalignment, sleep curtailment, work-family conflicts, and other factors. We tested a bright light countermeasure to enhance circadian adaptation on a counterclockwise rotation schedule. METHODS: Twenty-nine adults (aged 20-40 years; 15 women) participated in a 4-week laboratory simulation with weekly counterclockwise transitions from day, to night, to evening, to day shifts. Each week consisted of five 8-hour workdays including psychomotor vigilance tests, two days off, designated 8-hour sleep episodes every day, and an assessment of circadian melatonin secretion. Participants were randomized to a treatment group (N=14), receiving intermittent bright light during work designed to facilitate circadian adaptation, or a control group (N=15) working in indoor light. Adaptation was measured by how much of the melatonin secretion episode overlapped with scheduled sleep timing. RESULTS: On the last night shift, there was a greater overlap between melatonin secretion and scheduled sleep time in the treatment group [mean 4.90, standard deviation (SD) 2.8 hours] compared to the control group (2.62, SD 2.8 hours; P=0.002), with night shift adaptation strongly influenced by baseline melatonin timing (r2=-0.71, P=0.01). While the control group exhibited cognitive deficits on the last night shift, the treatment group's cognitive deficits on the last night and evening shifts were minimized. CONCLUSIONS: In this laboratory setting, intermittent bright light during work hours enhanced adaptation to night work and subsequent readaptation to evening and day work. Light regimens scheduled to shift circadian timing should be tested in actual shift workers on counterclockwise schedules as a workplace intervention.

Plum curculio (Coleoptera: Curculionidae) adult mortality and associated fruit injury after exposure to field-aged insecticides on tart cherry branches.

Plum curculio, Conotrachelus nenuphar (Herbst) (Coleoptera: Curculionidae), adults were exposed to field-aged residues of thiamethoxam, acetamiprid, thiacloprid, indoxacarb, or azinphos-methyl on tart cherry, Prunus cerasus L. variety Montmorency. At 1, 3, 7, and 14 d postapplication, fruit were sampled for chemical residues, and bioassays were used to assess beetle mortality and plant tissue injury. Azinphos-methyl had lethal activity within 1 d of exposure at all postapplication intervals and significant fruit protection extended to 14 d postapplication. All of the neonicotinoids had lethal activity at 3 d posttreatment, with acetamiprid activity extending to 7 d. Antifeedant and oviposition deterrent effects were seen with thiamethoxam and thiacloprid; damage incidence was significantly reduced in the absence of significant beetle mortality or intoxication. Thiamethoxam and acetamiprid penetrated into leaf and fruit tissue and were detected in the interior tissues at 14 d postapplication, but interior thiacloprid residues were not detected after day 1. Indoxacarb provided some fruit protection out to 7 d postapplication, and 14-d-old residues intoxicated beetles, but the slow action of this compound allowed significant damage to occur before beetles were incapacitated. Indoxacarb was only detected as a surface residue after the first day postapplication. These data on the plant-insect-chemistry interactions will support use and management decisions as compounds with acute contact activity are phased out.

Activity of broad-spectrum and reduced-risk insecticides on various life stages of cranberry fruitworm (Lepidoptera: Pyralidae) in highbush blueberry.

Laboratory and semifield bioassays were conducted to determine the life-stage activity of insecticides for controlling cranberry fruitworm, Acrobasis vaccinii Riley (Lepidoptera: Pyralidae), a key lepidopteran pest of highbush blueberry, Vaccinium corymbosum L. The organophosphates azinphosmethyl and phosmet, the pyrethroid esfenvalerate, and the carbamate methomyl were lethal to all life stages. The neonicotinoids thiacloprid and acetamiprid demonstrated strong larvicidal and ovicidal activity but were somewhat weaker adulticides than the conventional broad-spectrum compounds. Bacillus thuringiensis, indoxacarb, and emamectin benzoate were shown to control A. vacinii primarily through their larvicidal activity. Spinosad was toxic to all life stages, including eggs laid on top of residues and those that were treated topically, but larvicidal activity was short lived. The growth regulators pyriproxyfen and novaluron had strong ovicidal activity when eggs were laid on top of residues but had limited larvicidal activity. Tebufenozide was not directly toxic to eggs, but demonstrated larvicidal activity, and ovilarvicidal activity when topically applied to eggs. Azinphosmethyl, phosmet, indoxacarb, thiacloprid, and acetamiprid were all toxic to the egg parasitoid Trichogramma minutum Riley. In contrast pyriproxyfen, emamectin benzoate, methomyl, novaluron, and spinosad did not negatively affect the survival of T. minutum within Acrobasis vacinii eggs. These results help inform the ongoing development of integrated strategies for insect management in blueberry.

Organic Control of Pear Psylla in Pear with Trunk Injection.

Organic production of pears is challenging in part because OMRI (Organic Materials Review Institute) approved biopesticides are short lived when applied as foliar sprays. Trunk injection is an alternative method of insecticide delivery that may enhance the performance of biopesticides for control of pear psylla. The objective of this study is to compare the efficacy of azadirachtin and abamectin in the control of pear psylla using two different application methods, airblast sprayer and trunk injection. Trunk injections of azadirachtin and abamectin were compared to airblast applications of equal labeled rates on 33-year-old Bartlett Pear trees (Pyrus communis L., var "Bartlett"). The azadirachtin and abamectin trunk injected treatments performed equally or better than the two airblast applications in the control of the pear psylla. The trunk injected trees from the first season provided a moderate level of control into the second season, one year after the injections. This study suggests that trunk injection is a superior delivery system for biopesticides used in organic pear production.

Curative Activity of Insecticides Used to Control Spotted-Wing Drosophila (Diptera: Drosophilidae) in Tart Cherry Productions.

Spotted-wing drosophila (Drosophila suzukii Matsumura) is a major pest of soft-skinned fruit and due to the low infestation tolerance for marketable fruit, growers take preventive actions to hinder spotted-wing drosophila damages. Insecticides application is one of the measures taken by growers. Although intensive spraying programs have been used to manage spotted-wing drosophila, its early infestation, rapid reproduction, and vast range of host have caused damage to still occur in fruit, including tart cherries, Prunus ceraus (Linnaeus). Therefore, there is a merit for information on insecticide's curative activity to understand whether sprays manage spotted-wing drosophila individuals within infested fruit. Tart cherry fruit were exposed to spotted-wing drosophila adults for 3 d. After this infestation period, insecticides were applied 1 and 3 d later. Small larvae, large larvae, and pupae were counted 9 d after initial infestation. A parallel set of insecticide-treated tart cherries were subjected to residue analysis. Phosmet and spinetoram were able to reduced live spotted-wing drosophila counts compared with the control at all life stages and insecticide application times, whereas zeta-cypermethrin, acetamiprid, and cyantraniliprole were less consistent in reducing spotted-wing drosophila numbers. Chromobacterium subtsugae demonstrated no curative action. Residue analysis demonstrated that zeta-cypermethrin residues mostly remained on fruit surface. Small portions of phosmet, spinetoram, and cyantraniliprole were able to penetrate fruit surfaces and move into subsurface tissues. Acetamiprid was the only compound which >47% penetrated into the fruit subsurface consistently across both years. Curative activity demonstrated in this study can provide additional tactics for spotted-wing drosophila management in tart cherry Integrated Pest Management (IPM) programs.

Reduced egg viability in codling moth Cydia pomonella (L.) (Lepidoptera: Tortricidae) following adult exposure to novaluron.

BACKGROUND: The codling moth, Cydia pomonella (L.), is one of the principal pests of pome fruits in the world. The effects of novaluron, a benzoylurea chitin synthesis inhibitor insecticide registered for use on apples in the USA, on fecundity and egg viability in codling moth were studied under laboratory conditions. Three different exposure methods were investigated: ingestion, contact and topical spray. Additionally, the duration of novaluron sublethal effects was measured subsequent to the three modes of exposure. RESULTS: The fecundity of codling moth adults was not significantly affected by novaluron with any of the exposure methods. However, novaluron did cause significant reductions in the proportion of egg hatch with all three exposure methods. The duration of sublethal effects was 9 days or more for all modes of exposure, but with the topical spray these effects began to diminish after 6 days. CONCLUSION: Novaluron does not affect fecundity in codling moth, but has significant sublethal activity by reducing egg viability subsequent to adult exposure. The topical, contact and ingestion exposures all induce sublethal effects after exposure, and these persist to various degrees throughout codling moth oviposition. A more complete understanding of novaluron's lethal and sublethal activities will help IPM practitioners optimize its use for management of the codling moth.

Lethal and sublethal effects of chlorantraniliprole on three species of Rhagoletis fruit flies (Diptera: Tephritidae).

BACKGROUND: Chlorantraniliprole formulated as a 350 g kg(-1) WG (Altacor 35WG) for management of apple maggot Rhagoletis pomonella (Walsh), blueberry maggot R. mendax Curran and cherry fruit fly R. cingulata (Loew) (Diptera: Tephritidae) was evaluated in laboratory assays and field trials. RESULTS: A tarsal contact toxicity bioassay showed that a surface residue of 500 mg L(-1) of chlorantraniliprole caused significantly higher mortality of male and female flies of all species compared with a control. Male apple maggot and blueberry maggot mortality was significantly higher than that for females, but there was similar mortality of male and female cherry fruit flies. An ingestion toxicity bioassay showed that 500 mg L(-1) of chlorantraniliprole in diet caused significantly higher mortality of male and female flies of all species than the control, but there were no significant differences among the sexes. Delayed egglaying by females that had ingested chlorantraniliprole was found, but there were no significant sublethal effects on either the number of eggs laid or the egg hatch. Field trials with apple maggot and cherry fruit fly showed that protection of fruit by chlorantraniliprole was comparable with that of standard broad-spectrum insecticides. CONCLUSIONS: The present data indicate that chlorantraniliprole has suppressant activity against Rhagoletis fruit flies, preventing fruit infestation primarily through direct lethal effects.

Curative activity of insecticides on Rhagoletis pomonella (Diptera: Tephritidae) in apples.

Field-based experiments were used to determine the lethal activity of insecticides on apple maggot, Rhagoletis pomonella (Walsh) (Diptera: Tephritidae), eggs and larvae in apple (Malis spp.) fruit. The organophosphates azinphosmethyl and phosmet and the neonicotinoids thiacloprid, acetamiprid, clothianidin, and thiamethoxam showed significant curative activity on the apple maggot postinfestation, when applied topically to apple fruit 24 h postharvest. Of the compounds tested, only phosmet showed significant curative activity on apple maggot when applied 14 d postharvest. The pyrethroid esfenvalerate, oxadiazine indoxacarb, anthranilic diamide chlorantraniliprole, and spinosyns spinosad and spinetoram did not show activity on apple maggot eggs and larvae in fruit. Residue profiles showed that for most compounds, the majority (>85%) of residues were found in the skin and the outside 2 mm of the apple flesh. For the neonicotinoid compounds, however, substantial portions of residues were found to penetrate in and beyond the outer flesh regions, and the total flesh residue recoveries were generally greater than those from the skin. Residues of azinphosmethyl and phosmet were detected in all three flesh regions, with the largest proportions recovered from the skin.

Curative activity of insecticides against plum curculio (Coleoptera: Curculionidae) in tart cherries.

Tart cherry, Prunus cerasus L. variety Montmorency, fruit were infested with plum curculio, Conotrachelus nenuphar (Herbst) (Coleoptera: Curculionidae), and treated with insecticides to target late instars, neonates, and eggs. The organophosphates azinphos-methyl and phosmet and the neonicotinoid thiamethoxam reduced larval emergence rates by >90% for all life stage targets; after >30 d, few surviving larvae were found inside fruit. Acetamiprid and thiacloprid also had curative activity and yielded >75% reductions in emergence and few surviving larvae in the fruit after >30 d. The juvenile hormone analog pyriproxyfen reduced larval emergence, but 66% of fruit that was treated to target late-instars still had live larvae inside of them after >30 d. Novaluron, chlorantraniliprole, and esfenvalerate had no curative activity. Indoxacarb had limited curative activity, and all targeted life stages had larval emergence. Internal and external residues were analyzed and are discussed in relation to their penetration and curative potential. The curative activity of azinphos-methyl has played an important role in meeting federal standards for infestation-free tart cherries at processing. Regulatory changes are eliminating the use of this compound, and new integrated pest management programs for plum curculio will need to address the loss of azinphos-methyl's curative activity.

Paraffin wax emulsion for increased rainfastness of insecticidal bait to control Rhagoletis pomonella (Diptera: Tephritidae).

In regions with a humid summer climate, the use of water-soluble bait to control apple maggot is often limited by rainfall. We studied increasing the rainfastness of GF-120 fruit fly bait by adding paraffin wax emulsion. First, we verified that adding 10% wax to a mixture containing 16.7% GF-120 did not reduce the mortality of female apple maggot compared with GF-120 without wax. In addition, we determined that fly mortality caused by GF-120 plus wax subjected to simulated rain was similar to that caused by GF-120 without wax not subjected to rain. Other assays showed that higher fly mortality resulted from increasing the proportion of wax from 10 to 15%, and lower mortality resulted from decreasing GF-120 from 16.7 to 10 or 5%. The availability of spinosad on or near droplets of a mixture consisting of 5, 10, or 15% GF-120 and 15% wax was determined before and after the droplets were subjected to three 15-min periods of simulated rain. We found an initial steep decline in dislodgeable spinosad and smaller decreases after subsequent periods of rain. In a small-plot field trial, fruit infestation by apple maggot in plots treated with a mixture consisting of 16.7% GF-120 and 19.2% wax was less than in plots treated with 16.7% GF-120 without wax but not less than in control plots. Overall, we found that adding paraffin wax emulsion to GF-120 increased rainfastness in laboratory bioassays, and specifically that it retained the active ingredient spinosad. However, our field data suggest that optimal rainfastness requires the development of mixtures with > 19.2% wax, which may preclude application using standard spray equipment.

Residual Toxicity of Insecticides to Neoseiulus fallacis (Acari: Phytoseiidae) in Apples.

Neoseiulus fallacis (Garman) is a predatory mite that is common in apple orchards and distributed throughout North America. However, N. fallacis may be susceptible to pesticides used for the management of crop pests. This study aimed to evaluate the temporal effects of commonly used insecticides on N. fallacis survival. Neoseiulus fallacis adults were exposed to field-aged residues, and mortality and lethal time were measured over 96 h of exposure. Carbaryl caused high mortality to N. fallacis and the shortest lethal time values (LT50), followed by spinetoram, with moderate lethal time values. Esfenvalerate, acetamiprid, chlorantraniliprole, and novaluron showed little to no lethality to N. fallacis following exposure to dry field-aged residues. The results of this study provide important field-relevant knowledge that is often void from laboratory-based studies, which can aid integrated pest management (IPM) decision-makers in apple production systems.