Washington Tree Fruit Research Commission

Dynamic controlled atmosphere (DCA) storage offers potential economic advantage for organic apple storage, but quantifying these benefits requires accounting for packout uncertainty, seasonal price dynamics, environmental, and location-specific heterogeneity. We developed an integrated empirical simulation that links multiyear storage trials with Monte Carlo revenue modeling to quantify DCA performance relative to controlled atmosphere and regular atmosphere storage. Storage experiments evaluated quality retention or packouts across storage durations and were represented by beta-distributions. A three-stage least squares model identified seasonal price patterns and key determinants of organic apple prices, producing monthly price predictions. Predicted prices were combined with simulated packouts to estimate by cultivar, storage length, and orchard the probability that DCA is revenue superior. Economic outcomes were cultivar, year, and site specific. For organic ‘Gala’ ( Malus domestica ), the probability that DCA dominates increased from 37.6% in Spring 2022 to 91.8% in Summer 2024, with median revenue advantages for DCA reaching $170,488 per storage room at peak. For ‘Honeycrisp’, orchard-level heterogeneity was pronounced. Orchard 1 achieved 100% DCA dominance in Spring 2024, whereas ‘Honeycrisp’ orchard 2 showed variable performance (high of 77.0% to 78.6% in Summer 2022 and Summer 2023). Weather-sensitivity analysis indicated location-specific responses. Elevated harvest temperatures slightly reduced DCA dominance for ‘Gala’ but sharply reduced it for ‘Honeycrisp’ (−26.1 percentage points on average). These findings indicate that DCA adoption should be tailored to cultivar, storage duration, and local environmental conditions. The framework provides probabilistic decision support for adoption and timing of DCA in organic apple supply chains by integrating storage performance, price seasonality, and packout uncertainty.

Crop load management of apple is one of the most important management practices for ensuring consistent annual yields of high-quality fruit. A previously developed fruit set prediction model, coined the FGR (Fruit Growth Rate) was shown to predict apple fruit set within 7 to 8 days of chemical thinning. Although this could aid repeat thinning decisions, the FGR model had not been widely adopted due to the time demand for implementation. The objective of the current research was to develop a user-friendly alternative using the conceptual framework of the FGR model to generate fruit set predictions. Because fruitlet weight was highly correlated to fruitlet diameter, fruitlets were assessed by mass using an automated balance with a data export function to an Excel program. Without the need for repeated measures of fruit growth and manual data entry, the method was tested alongside the FGR model using two commercially important cultivars, Gala and Honeycrisp, in four distinct locations of the United States: Michigan, New York, North Carolina, and Washington. At all sites, post-bloom chemical thinning applications were made over a range of developmental timings according to fruitlet diameter and weather conditions. A given model’s capacity to generate a prediction was considered successful if the accuracy of the fruit set prediction was within ± 10% of the absolute fruit set observed at “June drop.” Over the course of 12 separate experiments, the FSD model (fruitlet size distribution) successfully predicted fruit set in 83% of trials; this was markedly higher than the FGR (67% success rate). However, the FGR model, when accurate, returned a prediction by 5.5 days (±0.7 day), which was 2.8 days earlier than the FSD. When thinners were applied before 6-mm fruitlet diameter, both models returned a prediction when fruitlets would still be considered susceptible to select thinning chemistries. When thinner applications were delayed until later fruitlet development stages, a 2.8-day delay in the prediction could limit repeat applications given increasing fruitlet resistance to thinners with time. Model validation under disparate regions, cultivars, and years produced consistent results and may improve labor-use-efficiency and precision management of apple fruit set, especially in combination with bloom and early fruitlet (∼≤6 mm diameter) thinning.

Since its detection in the continental United States in 2008, spotted-wing drosophila (Drosophila suzukii Matsumura) has become a significant pest of thin-skinned fruits. Current management strategies largely depend on calendar-based insecticide applications, which have disrupted previously established integrated pest management programs. Alternative control tactics, such as behavioral manipulation with phagostimulants, are being explored to reduce dependence on insecticides. In this study, we evaluated the effects of adding the commercial phagostimulant Combi-protec Insect Bait Attractant on the efficacy of insecticides targeting D. suzukii. The study was conducted across 6 US states (New Jersey, Georgia, Michigan, Oregon, Maine, and New York) under field conditions using highbush blueberries, lowbush blueberries, and raspberries. Treatments were applied in the field under caged conditions in 2021 and open conditions in 2022, followed by laboratory bioassays to assess adult mortality, oviposition, and larval infestation/emergence. When adults were exposed to freshly treated materials, insecticide treatments combined with Combi-protec generally performed as well as, or better than, insecticides alone in highbush blueberries (particularly spinetoram and phosmet); however, inconsistent results were observed in lowbush blueberries and raspberries. As materials aged in the field, efficacy across treatments declined, leading to variable results. Oviposition patterns closely mirrored adult mortality, but the treatment effects on developing larvae and emerged progeny were inconsistent or negligible. Overall, Combi-protec enhanced the efficacy of insecticides against adult D. suzukii, though its benefits for subsequent life stages were inconsistent. These findings provide new insights into the potential role of phagostimulants for improving insecticide effectiveness for D. suzukii control.

This study examined the attachment, persistence, and fate of Listeria monocytogenes on selected varieties of fresh pears during simulated extended storage, along with the dynamics of resident yeast and mold (Y&M) populations. Following inoculation with ~7.0 log CFU/mL, L. monocytogenes exhibited varying attachment efficiencies across pear varieties, resulting in 6.23 ± 0.03, 6.30 ± 0.01, and 5.12 ± 0.01 log CFU/pear on Bartlett, d'Anjou, and Bosc pears, respectively, after 24 h. The L. monocytogenes population gradually declined on pear surfaces during storage. After 14 days, L. monocytogenes populations decreased to ~4.20, 5.96, and 4.07 log CFU/pear on Bartlett, d'Anjou, and Bosc pears, respectively, regardless of temperature, and remained stable over the subsequent 14 days. During 20-week storage at 0 °C, the L. monocytogenes level decreased by 2.65-3.84 log CFU/pear on all pear varieties. Y&M levels varied across pear varieties and crop years. The initial Y&M counts for Bartlett, d'Anjou, and Bosc in year 2 were 4.37 ± 0.01, 5.93 ± 0.02, and 5.11 ± 0.03 log CFU/pear, respectively. The Y&M levels of d'Anjou and Bosc for years 1 and 2 were 4.73-4.79 and 5.11-5.93 log CFU/pear, respectively. During 20-week storage at 0 °C, Y&M counts generally increased, with Bartlett pears exhibiting a more pronounced rise after 12 weeks. Data indicated that L. monocytogenes did not grow on pears; instead, its population declined under all simulated storage conditions, offering practical guidance for pear packers on Listeria behaviors under various storage conditions.

Abstract Plant breeding in the public sector is a multigenerational process that creates new plant varieties intended to meet current and future needs of society. Many public sector plant breeding programs are over a century old, and they continue to curate plant genetic resources that are far older still. While individual breeders serve as temporary leaders of these programs and the plant genetic resources they maintain, it is only their institutions that have the capacity to provide the necessary generational glue, enabling the accrual of long‐term value to both breeders and society. Identifying best practices to ensure mutual benefit to both public sector breeders and their institutions is critical to achieving the smooth leadership transitions necessary for the sustainability and long‐term impact of public breeding programs. The findings presented here suggest that the successful passing of the torch in such programs depends not only on strategic institutional support but also, critically, on the routine actions and mindset of the breeders entrusted with their leadership.

The European earwig, Forficula auricularia L. (sensu lato), has a dual role in temperate tree fruit crops-a pest of stone fruit and a predator of key pests in pome fruit. Some growers trap earwigs in crops where they are pests, subsequently releasing them in pome fruit as an augmentative biological control strategy. Effective earwig monitoring and trapping are critical for understanding their biological control potential in orchards. Traps made of rolled, corrugated cardboard have long been used for earwig monitoring; however, no standardized studies have investigated improvements to them. In a series of trials, we explore options to improve traps by testing different trap materials, sizes, positioning on the tree, and time in the field, in addition to the lures and baits. We found that cardboard traps had higher earwig catch than black or translucent plastic traps. There were diminishing returns in earwig capture for increased trap length, plateauing at ~30 cm. Traps placed on the main trunk captured more earwigs than traps on the base or near the end of branches. Lures and baits mostly did not increase trap efficacy, except fish sauce which inconsistently increased earwig captures. The use of plastic bottles to contain the cardboard traps greatly reduced trap catch. Finally, we found evidence that traps left in the field for longer periods of time can increase earwig capture, possibly due to the accumulation of earwig aggregation pheromone. Overall, the standard unbaited corrugated cardboard trap was the most effective and practical earwig monitoring trap.

Conservation biological control in agriculture primarily relies on avoiding pesticides that may harm key natural enemies. In temperate tree fruit crops, the European earwig, Forficula auricularia (L.) has only recently become appreciated as an important predator of economic pests, particularly woolly aphids and pear psylla. Therefore, the non-target effects of orchard pesticides on earwigs are largely understudied. This is particularly true for herbicides, which earwigs are likely to be exposed to due to their foraging behavior moving between the canopy and the ground cover. We tested residues of formulated pesticides (8 insecticides and 7 herbicides) commonly used in tree fruit crops for lethal and sublethal (movement, predation rate) effects on adult female earwigs. Two herbicides, paraquat and glufosinate, and one insecticide, spinetoram, were acutely toxic to earwigs within 72 h. No tested pesticides altered earwigs' movement or resting behavior compared to the control. The insecticides spinosad and cyantraniliprole and the herbicides 2,4-D, glufosinate, halosulfuron, rimsulfuron, and oxyfluorfen reduced earwig predation on green peach aphids. Therefore, these pesticides may reduce earwig predation on pests in orchards. Our results suggest that some pesticides are of greater risk, and thus, should be carefully considered or better timed when used in tree fruit orchards where earwigs are considered for conservation or augmentative biological control.

Abstract European earwig, Forficula auricularia L. sensu lato (Dermaptera: Forficulidae), is a univoltine, resident, omnivorous species and a beneficial predator in pome fruit orchards. Here, three methods were used to investigate pear (Pyrus communis L., Rosaceae) orchard inoculation with European earwig for biocontrol of pear psylla, Cacopsylla pyricola (Foerster) (Hemiptera: Psyllidae), in Washington State, USA. The first method was earwig inoculation experiments. In a first experiment (2019–2020), each of three orchards had one inoculation and one control plot. In a second experiment (2020–2021), there were four inoculation and four control plots in each of the same three orchards. In both experiments, earwigs persisted during the year of inoculation, but earwigs were nearly absent the following season at two orchards that used conventional broad‐spectrum pesticides. At the third orchard, which excluded broad‐spectrum pesticides under an integrated pest management (IPM) program, earwigs became abundant in year two of the second experiment. The second method was case studies. In the first of two case studies, during 2016, 2017, 2022, and 2023, in half of the integrated orchard from above, conventional broad‐spectrum sprays were used. Earwig populations became low in the conventional half. In the second case study, earwigs became abundant after inoculation of an integrated orchard by the grower. Earwigs spread to the edge of the orchard in year two and spilled into a neighboring orchard in years three and four. The third method was an observational study of 36 pear orchards over 5 years. Earwigs were rarely found in conventionally sprayed orchards, and earwigs increased each additional year integrated management was used. The findings suggest conventional pear spray programs in Washington nearly eradicate earwigs, but populations can recover under integrated management with natural dispersal from refuges or with inoculative releases.