Residue profiling was used to determine the rainfastness and corresponding efficacy of two contact and one translaminar fungicide after 0, 6.3, 12.7, and 25.4 mm of simulated rainfall. Field studies were used to determine efficacy of the remaining residue after the simulated rainfall events. The fungicides tested were Captan, Mancozeb, and Pydiflumetofen. A sticker adjuvant was added to evaluate efficacy differences. The effect of rainfall was variable on the fungicides, and the addition of a sticker proved useful under certain conditions. Rates of scab infection were measured as a percent of infected leaves. This study showed that there was a significant loss of apple scab control for all three fungicides after 25.4 mm of rainfall, a significant loss of control for Mancozeb and Pydiflumetofen after 12.7 mm of rainfall, and loss of control with Pydiflumetofen after 6.3 mm of rainfall. The addition of a sticker improved the performance of Mancozeb after 0 and 12.7 mm, and 6.3 mm rainfall for Pydiflumetofen. This study will help apple growers make informed decisions following rain events and the corresponding impacts on fungicide retention.

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.

The gall wasp, Hemadas nubilipennis Ashmead, is a pest of highbush and lowbush blueberry and can pose a challenge to control with foliar sprays due to adult activity being during bloom and because larval development is within plant tissues. We hypothesized that systemic insecticides that move within the blueberry vascular system would reach areas where H. nubilipennis eggs are laid, causing larval mortality. Three application methods, crown injection, soil drench, and foliar spray were applied to potted 'Jersey' blueberry bushes at 50% and 100% rates to quantify systemic residue concentrations in shoots and leaves. Additionally, systemic insecticides were evaluated for control of gall wasps using single-shoot bioassays and measuring larval mortality at 0.01%, 0.1%, 1%, and 10% of field rate provided within a floral pick. Systemic insecticides tested in both studies included imidacloprid, flupyradifurone, and spirotetramat. The potted bush residue study determined that insecticides moved from three tested sites of entry: the roots, crown cavity, and foliage. Results from the shoot bioassays found that the mean percent larval survival of H. nubilipennis was negatively correlated with the concentration of AI detected in galls. Imidacloprid and spirotetramat were found to have the greatest potential for control of H. nubilipennis due to mortality in the shoot bioassays and similar residue concentrations in the potted bush studies to shoot bioassays. Future research should evaluate systemic insecticides applied in highbush blueberry plantings for control of H. nubilipennis using the bioassay mortality assessment method developed in this study.

Abstract 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.

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.

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.

In highbush blueberries,Vaccinium corymbosumL., three sprayers and two water spray volumes were compared for spray coverage and control of key insect pests and diseases. For evaluation of coverage in 2007, sprayers applied kaolin clay to bushes and percent surface area of black cards covered by kaolin was analyzed. In 2008, bushes were sprayed with methoxyfenozide and captan, and the material deposited on leaves or fruit was measured with HPLC or MS. In general, coverage varied significantly when an airblast, tower or cannon sprayer was utilized, and significant variation in pest and disease control was observed between water volumes.

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.

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.

Tart cherry production is challenged by precipitation events that may reduce crop protection against spotted-wing drosophila (Drosophila suzukii) (SWD). Due to SWD’s devastating impacts on yield, growers are often faced with the option of insecticide reapplication. Semi-field bioassays were used to assess simulated rainfall effects towards adult mortality, immature survival, and residue wash-off from different plant tissues for several compounds. Tart cherry shoots were treated with 0, 12.7 or 25.4 mm of simulated rainfall and infested with SWD for 5 days. Adult mortality was recorded 1, 3, and 5 days after shoots were infested, while immature stage individuals were counted 9 days after the first infestation day. All insecticides demonstrated higher adult mortality and lower immature survival compared with the untreated control at 0 mm of rainfall. Adult mortality and immature survival caused by phosmet, zeta-cypermethrin, and spinetoram were adversely affected by simulated rainfall. In all bioassays, acetamiprid was the least affected by simulated rainfall. Residue analysis demonstrated phosmet and spinetoram residues to be the most sensitive to wash-off. This study demonstrates different rainfall effects on SWD control for several compounds. This information may provide a basis for making an informed decision on whether reapplication is required.

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.

Soil columns were collected from a blueberry field, and insecticide solutions were allowed to leach through these columns. Insecticides from four different chemical classes were applied at two different rates: the concentration at which the insecticides wash off blueberries under rainfall conditions and the labeled field rate at which they are sprayed. The soil columns were divided into thirds; top, middle and bottom. Soil bioassays using Eisenia foetida Savigny, as an indicator species, were set up to determine the toxicity of the insecticides at a top, middle and bottom layer of the soil column. The mass of E. foetida was also measured after the bioassay experiment was completed. The concentrations at which insecticides wash-off of blueberries from rainfall were not lethal to E. foetida. In order to support mortality data, insecticide residues were quantified in the soil layers for each insecticide. Under field rate leaching conditions, carbaryl showed the high levels of toxicity in the top and middle layers of soil suggesting that it has the highest risk to organisms from leaching. This study will help blueberry growers make informed decisions about insecticide use, which can help minimize contamination of the environment.

BACKGROUND Trunk injection is an established method for delivering pesticides in ornamental and shade trees, but further research is needed to determine efficacy and pollinator safety in tree fruit crops. Apple trees were injected in 2013 and 2014 with the insecticides emamectin benzoate, imidacloprid, dinotefuran, spinosad, chlorantraniliprole, or abamectin. Additional emamectin benzoate and imidacloprid injections were performed in the spring and fall of 2015. Nectar and pollen were sampled in the following spring to compare the effects of application timings on insecticide loading into flowers. RESULTS Neonicotinoids reduced Empoasca fabae density in the field. Emamectin benzoate, chlorantraniliprole, and abamectin resulted in moderate to high mortality and reduced Choristoneura rosaceana feeding in bioassays. Imidacloprid was not detected in nectar or pollen when injected in the spring, and was detected at 0.39 ng g(-1) in pollen when injected the previous fall. Emamectin benzoate was not detected in nectar or pollen when injected the previous fall, and was detected at 7.36 ng g(-1) (nectar) and 1.15 ng g(-1) (pollen) when injected in the spring. CONCLUSIONS This study identified a broader list of possible trunk-injectable pesticides for apple trees. This study also shows that managing the seasonal timing of injection can reduce the risk of insecticide exposure to pollinators. (c) 2018 Society of Chemical Industry

We evaluated the potential for using preplant trunk injections of emamectin benzoate in nonbearing apple trees. Trees were evaluated for pest injury and emamectin residues throughout the planting season and into the following year. Injections into the trunk best delivered emamectin benzoate to the canopy compared with injections into the taproot, and the higher rate reduced insect pests more than the lower rate. In the following year, differences in insect control between trunk and root injections were less pronounced, but the higher rate of emamectin benzoate persisted longer and better reduced pests relative to the other treatments.

Semi-field studies were used to evaluate the effects of rainfall and field ageing on the performance of insecticides from six different chemical classes used to control the codling moth (Lepidoptera: Tortricidae). All insecticides were significantly more toxic to codling moth larvae than the untreated control, although seven-day field ageing reduced control for several compounds. Simulated rainfall events of 2.54 and 12.7mm did not have negative effects on the performance of the insecticides. Simulated rainfall events of 50.8 mm of rainfall resulted in significant reductions of efficacy for thiacloprid and spinetoram. Residue profiles of apple leaves and fruit provided evidence for wash-off ranging from 13% to 93%, with patterns varying by compound, plant substrate, and rainfall level. This study will help apple growers make informed decisions on when reapplications of insecticides are needed in the field with the aim of improving integrated pest management.

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.

Neoseiulus fallacis (Garman) (Acari: Phytoseiidae) is an efficient predator of the European red mite (ERM) (Panonychus ulmi (Koch); Acari: Tetranychidae) in Michigan, United States of America apple orchards and an important part of integrated pest management. Four reduced-risk insecticides (acetamiprid, spinetoram, chlorantraniliprole, and novaluron) and two conventional insecticides (esfenvalerate and carbaryl) were tested against N. fallacis for topical toxicity effects. Bioassays using a Potter spray tower were conducted to measure the topical toxicity of compounds when applied at field rate concentrations to N. fallacis. Lethal time was measured for adult N. fallacis at 4, 24, 48, 72, and 96 hours after treatment. Carbaryl and esfenvalerate showed the highest levels of toxicity to adult N. fallacis with shortest lethal time values (LT50) whereas the reduced risk insecticides novaluron, acetamiprid, spinetoram, and chlorantraniliprole were nontoxic. This study provides important information to apple growers regarding direct lethal effect of insecticides on predator mites and its implications to integrated mite management.

Semi-field experiments were used to compare the curative activity of insecticides on spotted-wing drosophila (Drosophila suzukii (Matsumura) (Diptera: Drosophilidae)) and blueberry maggot (Rhagoletis mendax Curran (Diptera: Tephritidae)) in blueberry fruit. The organophosphate phosmet, the spinosyn spinetoram, and neonicotinoids imidacloprid, acetamiprid, and thiamethoxam showed significant lethality on spotted-wing drosophila and blueberry maggot larvae and eggs, when applied topically to blueberry fruit post-infestation. The pyrethroids fenpropathrin and zeta-cypermethrin showed high levels of post-infestation activity on spotted-wing drosophila larvae or eggs, and indoxacarb showed statistically weaker activity. Curative activity is a previously unrecognised contributor to the overall means by which blueberry growers may achieve control of spotted-wing drosophila and blueberry maggot with the use of insecticides in blueberries.

The obliquebanded leafroller (OBLR), Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae), has become a significant pest of tree fruit production in North America within the past 25 years. Control of the OBLR has historically relied upon broad-spectrum insecticides like organophosphates, carbamates, and pyrethroids. However, with evidence of resistance development, newer chemistries have been developed to combat this pest. The effects of novaluron, a chitin synthesis inhibitor, were studied to determine if reduced egg hatch occurs after exposure to adults. The transovarial effects of this compound were tested through laboratory bioassays, looking at decreased egg hatch and also presence of novaluron in egg masses following adult exposure. Results from the study demonstrated a decrease in egg hatch after adult exposure. Analysis of egg mass using HPLC also demonstrated novaluron present in the eggs laid by treated adults. Along with the direct ovicidal and larvicidal properties of novaluron, this transovarial activity provides an important contribution to the overall control seen in the field.

BACKGROUND Pesticide use in orchards creates drift-driven pesticide losses which contaminate the environment. Trunk injection of pesticides as a target-precise delivery system could greatly reduce pesticide losses. However, pesticide efficiency after trunk injection is associated with the underinvestigated spatial and temporal distribution of the pesticide within the tree crown. This study quantified the spatial and temporal distribution of trunk-injected imidacloprid within apple crowns after trunk injection using one, two, four or eight injection ports per tree. RESULTS The spatial uniformity of imidacloprid distribution in apple crowns significantly increased with more injection ports. Four ports allowed uniform spatial distribution of imidacloprid in the crown. Uniform and non-uniform spatial distributions were established early and lasted throughout the experiment. The temporal distribution of imidacloprid was significantly non-uniform. Upper and lower crown positions did not significantly differ in compound concentration. Crown concentration patterns indicated that imidacloprid transport in the trunk occurred through radial diffusion and vertical uptake with a spiral pattern. CONCLUSION By showing where and when a trunk-injected compound is distributed in the apple tree canopy, this study addresses a key knowledge gap in terms of explaining the efficiency of the compound in the crown. These findings allow the improvement of target-precise pesticide delivery for more sustainable tree-based agriculture.