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The azalea lace bug, Stephanitis pyrioides, is a serious pest of azaleas and rhododendrons which is often controlled by systemic insecticides. However, the efficacy of softer approaches such as biological control and water sprays against this pest on rhododendrons is unknown. Therefore, we tested the commercially available green lacewing predator, Chrysoperla rufilabris, and water sprays on lace bug infestation in one laboratory and four field trials. First, 2nd instar predator larvae were confirmed to consume lace bug nymphs and sometimes adults. Second, tapping predator larvae from hexcel units over dry leaves of potted rhododendrons and shaking loose eggs over wet leaves were reliable application methods. Third, predator larvae released onto potted rhododendrons lowered lace bug counts for two weeks. Fourth, after four bi-weekly applications, plants receiving egg cards or water-sprays had reduced lace bug counts and fewer damaged leaves than control plants. Fifth, landscape plants receiving the sequential combination of water spray followed by predator egg releases had 44 to 90% lower lace bug abundance and fewer damaged leaves than the control. After lace bugs were initially dislodged, hatching predators might have consumed hatching lace bugs. Index words: biological control, Chrysoperla rufilabris (Burmeister), mechanical control, rhododendron, Stephanitis pyrioides (Scott) Species used in this study: Azalea lace bug (Stephanitis pyrioides Scott), green lacewing (Chrysoperla rufilabris Burmeister), Rhododendron (Rhododendron spp.)

Drosophila suzukii is widely studied because of its status as a global pest of berries and soft fruits. Environmental conditions and access to food resources impact the physiology and fitness of D. suzukii; these factors could also affect dispersal. Flight mills are a convenient tool for measuring and comparing the flight performance of insects. In this study, two experiments examined the effects of diet and humidity on D. suzukii flight performance using custom-built flight mills, and a third experiment compared the energy reserves of D. suzukii flown or not flown on flight mills. Over all flight assays, the median flight distance and duration were 27.16 m and 2.37 min, respectively, and the mean flight velocity was 0.18 m/s. The maximum flight distance and duration by an individual were 1.75 km and 2.35 h, respectively. Drosophila suzukii provisioned with blossoms, fruits, or standard laboratory diets flew farther distances and longer durations than starved flies. While starvation was associated with reduced flight performance, there were no observed differences between diet types. It remains unclear whether D. suzukii consistently use lipids, glycogen, sugar, or another energy source for flight because tethered individuals may not have flown enough to deplete energy reserves. Humidity did not affect flight performance of D. suzukii within a ~ 2 h test period. These data indicate that most D. suzukii are likely to remain within limited area (e.g., within a field) but that some individuals can disperse long distances (field to field spread).

Biocontrol may play an important role in IPM of D. suzukii, a worldwide fruit crops pest. Predation on D. suzukii has been observed in the field, but rates have not been measured. Additionally, targeting juveniles may be more effective than targeting adults for reducing population sizes. The first objective of this study was to measure naturally-occurring levels of biocontrol on D. suzukii juveniles. Furthermore, D. suzukii may either pupate inside of fruit or emerge to pupate in the soil. Knowing the location of pupae can be important for developing biological and cultural control programs. The second objective of this study was to determine the proportion of D. suzukii pupating in fruit versus soil. Predator exclusion experiments were conducted to measure the ability of natural enemies to reduce D. suzukii larvae in strawberry and blueberry fruits, and pupae in the soil underneath strawberry, blueberry, and blackberry. Funnels were used to direct larvae dropping from infested blueberry and raspberry fruits into soil-filled containers. Significantly fewer D. suzukii larvae were extracted from fruits exposed to predators, representing a reduction in larval survival of 19–49%. Significantly fewer D. suzukii pupae were recovered from soil exposed to predators, representing a 61–91% decrease in pupae. In the pupation behavior experiment, 82–93% of pupae were found in soil, significantly more than were found in fruit. Ants and spiders were commonly observed in a variety of sampling methods, and ants were observed on video to remove pupae from the soil.

Drosophila suzukii (Matsumura) is an economic pest of small fruits and cherries that attacks intact ripening fruits. Host susceptibility may be influenced by characteristics such as flesh firmness, penetration force of the skin, total soluble solids (TSS, also known as °Brix), and pH. Improved knowledge of factors affecting fruit susceptibility is needed for developing thresholds and risk prediction models for IPM. A combination of laboratory and field studies was conducted to develop prediction and potential management tools. First, a direct bioassay was used to calculate the probability of oviposition in a given fruit based on various characteristics as determined across laboratory and field trials in Oregon and North Carolina, US. When multiple characteristics were evaluated simultaneously, oviposition probability consistently increased as penetration force decreased and pH increased. Oviposition probability sometimes increased as TSS increased. Second, raspberries and blueberries in unsprayed fields had substantially lower infestation in ripening fruit compared to ripe fruit. There was no or minimal infestation in green fruit. Third, given that skin penetration force influences oviposition, practices used to improve fruit quality were examined in laboratory no-choice cages for potential reduction of oviposition. Blueberry fruit sprayed with calcium silicate in the field had greater penetration force and firmness and reduced number of eggs laid by D. suzukii compared to untreated fruit. Other calcium-based treatments increased Ca content and firmness of fruit relative to untreated fruit. Timing of insecticide spray for D. suzukii might be delayed until fruit become susceptible.