Herbaceous flowering or woody plant borders adjacent to highbush blueberry (Vaccinium corymbosum) fields have the potential to benefit both native pollinators and species of predatory and parasitic arthropods and birds that feed on key highbush blueberry pests, such as spotted wing drosophila [SWD (Drosophila suzukii)]. However, they may also draw pollinators away from the crop, serve as overwintering and/or refugia sites for SWD, and increase the abundance of wild birds that feed on fruit and harbor foodborne pathogens. The objective of this 1-year, observational study was to explore the potential impacts of border vegetation adjacent to commercial highbush blueberry fields on pollination, crop productivity, and arthropod and bird communities within the Pacific Northwest region in the United States. The study included three highbush blueberry cultivars (Duke, Draper, and Liberty), and three field border vegetation treatments: 1) woody perennial vegetation; 2) herbaceous vegetation; and 3) medium-height grasses (control). There was one border treatment per cultivar for a total of nine sites. No cultivar effects nor interactions for any of the variables were detected, so results were combined across cultivars. No differences in pollinator abundance, pollinator visitation rates, estimated yield, berry weight, and seed number were observed across the treatments. Herbaceous borders had more natural enemies than the woody perennial borders, but both were similar to the control. This trend is attributed to higher abundances of parasitic wasps (suborder Apocrita) in the herbaceous and control borders compared with the woody perennial borders. Increased abundances of aphids (family Aphididae), a host for parasitic wasps, likely influenced these results. Differences in predatory arthropods were not observed. Insect abundances were overall low in all field sites measured in this study, likely influenced by SWD insecticide applications. There were no differences in total wild bird density by treatment except for barn swallows (Hirundo rustica), which were greatest in the control treatment. Overall, the border treatments evaluated in this study had small-to-negligible impacts on the measured variables, and there was no clear crop production benefit. Additionally, none of the investigated border treatments negatively impacted highbush blueberry production. Taken together, border vegetation treatments can provide benefits such as reducing pesticide drift, deterring trespassers, and serving as a windbreak; but any potential benefits from a pollination or biocontrol aspect are likely diminished due to current SWD management practices.

Perennial fruit crops are traditionally grown in systems without plastic mulch. However, there may be benefits to plastic mulch use and this review paper considers the use of plastic mulch in perennial fruit systems. Several studies have explored the use of non-biodegradable plastic mulches [polyethylene (PE) and polypropylene (PP)] in perennial fruit production systems and have demonstrated the positive impacts they can have on plants largely through modification of the soil environment. Unfortunately, PE and PP mulches are difficult to dispose of due to contamination and lack of recycling facilities and contribute to plastic waste generation. Soil-biodegradable plastic mulches (BDMs) are alternatives to PE and PP mulches and are designed to be tilled into soil and degrade by soil microbial activity. A few studies have evaluated BDM in perennial fruit production systems and have shown similar impacts on crop growth as PE and PP mulches. The choice of plastic mulch (PE, PP, and BDM) to use in a perennial fruit production system will impact plant growth and productivity, the soil environment, and management of pests and diseases, as well as other soil fauna. Overall, there is no one-size-fits-all plastic mulch in perennial fruit production systems, and mulch choice should be based on the specific crop, growers’ horticultural goals and philosophies, climatic and soil conditions, expected mulch longevity, affordability, commercial availability, and the type of production system (e.g., conventional versus organic). BDMs are presently not widely used in perennial fruit crop production but could be a more sustainable option relative to traditional plastic mulches. Future research should continue to explore different plastic mulch options and investigate long-term impacts of plastic mulches in perennial fruit cropping systems.

Drosophila suzukii causes economic damage to berry and stone fruit worldwide. Laboratory-generated datasets were standardized and combined on the basis of degree days (DD), using Gompertz and Cauchy curves for survival and reproduction. Eggs transitioned to larvae at 20.3 DD; larvae to pupae at 118.1 DD; and pupae to adults at 200 DD. All adults are expected to have died at 610 DD. Oviposition initiates at 210 DD and gradually increases to a maximum of 15 eggs per DD at 410 DD and subsequently decreases to zero at 610 DD. These data were used as the basis for a DD cohort-level population model. Laboratory survival under extreme temperatures when DD did not accumulate was described by a Gompertz curve based on calendar days. We determined that the initiation of the reproductive period of late dormant field-collected female D. suzukii ranged from 50 to 800 DD from January 1. This suggests that D. suzukii females can reproduce early in the season and are probably limited by availability of early host plants. Finally, we used the DD population model to examine hypothetical stage-specific mortality effects of IPM practices from insecticides and parasitoids at the field level. We found that adulticides applied during the early season will result in the largest comparative population decrease. It is clear from model outputs that parasitism levels comparable to those found in field studies may have a limited effect on population growth. Novel parasitoid guilds could therefore be improved and would be valuable for IPM of D. suzukii.

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.