Phenology of brown marmorated stink bug described using female reproductive development.

Temperature-based degree-day models describe insect seasonality and to predict key phenological events. We expand on the use of a temperature-based process defining timing of reproduction through the incorporation of female reproductive physiology for the invasive pentatomid species Halyomorpha halys, the brown marmorated stink bug. A five-stage ranking system based on ovary development was able to distinguish between the reproductive statuses of field-collected females. Application of this ranking method described aspects of H. halys' seasonality, overwintering biology, and phenology across geographic locations. Female H. halys were collected in the US from NJ, WV, NC, OR, and two sites in PA in 2006-2008 (Allentown, PA only) and 2012-2014. Results identify that H. halys enters reproductive diapause in temperate locations in the fall and that a delay occurs in developmental maturity after diapause termination in the spring. Modification of the Snyder method to identify biofix determined 12.7-hr photoperiod as the best fit to define initiation of reproduction in the spring. Applying the biofix, we demonstrated significant differences between locations for the rate at which the overwintering generation transition into reproductive status and the factors contributing to this difference require further study. For example, after including abiotic variables influencing development such as temperature and photoperiod (critical diapause cue), reproduction occurred earlier in OR and for an extended period in NJ. This data describe a method to investigate insect seasonality by incorporating physiological development across multiple regions that can clarify phenology for insects with overlapping generations.

Biology and Seasonality of the Reemergent Pest Rhynchaenus pallicornis (Coleoptera: Curculionidae) and Methods for Monitoring Its Abundance.

Rhynchaenus pallicornis (Say) is a pest of commercially grown apples in the upper Midwest. This historic pest has resurged and caused severe yield loss on farms using certified organic production practices. The life history and potential monitoring methods of R. pallicornis are presented. Seasonal abundance data were collected through beat and visual sampling. A phenological model was developed for R. pallicornis. The minimum developmental threshold of R. pallicornis was determined to be 3.5°C with a required degree-day accumulation of 125°D for first adult emergence. Larval damage was observed on >60% of leaves in unmanaged orchards and affected significantly fewer basal leaf clusters (near the trunk), than medially or apically located clusters. Of 2,900 R. pallicornis larval mines collected over two years at three different sites, 18.0% produced at least one adult parasitoid, but the targeted larval stage is unknown. Measurements of R. pallicornis larval head capsules and the simple frequency method were used to determine three larval instars of R. pallicornis The number of larval instars could also be accurately determined by observing the presence or absence of two sets of thoracic sclerites. Pyramid traps, yellow sticky cards baited with olfactory cues (pear essence, benzaldehyde, and an aggregation of adult R. pallicornis) were evaluated as R. pallicornis monitoring tools. None of the traps or lures tested significantly affected the number of adult R. pallicornis per trap.

Identifying a Potential Trap Crop for a Novel Insect Pest, Halyomorpha halys (Hemiptera: Pentatomidae), in Organic Farms.

The invasive brown marmorated stink bug, Halyomorpha halys, poses significant risk to organic farming systems because they rely on biological control, nonsynthetic inputs, and cultural tactics for pest management. This study evaluated the potential of five crop plants (sorghum, admiral pea, millet, okra, and sunflower) to be used as trap crops under organic production in four mid-Atlantic states. Stink bug (H. halys and endemic species) densities and host plant phenologies were recorded weekly (mid-June through September). Sorghum attracted significantly more H. halys than the other crops evaluated, followed by sunflower and okra. Seasonal average H. halys density was 1.5-4× higher on sorghum than the other crops (P < 0.05), depending on site. Endemic stink bugs were equally attracted to all crops except admiral pea. A significant effect of time was detected (P < 0.0001), with H. halys densities initially higher on sunflower; as the sunflower senesced, sorghum supported significantly higher average H. halys densities. While sunflower and sorghum phenologies differed, these crops together provided a 5-wk attraction period coinciding with peak H. halys activity. The efficacies of pheromone-baited traps, flaming, applying OMRI-approved insecticides (Azera and Venerate), and vacuuming to removing stink bugs were evaluated as a management tactic. Flaming was the most effective treatment against H. halys and endemic stink bugs. Our results suggest that a trap crop composed of sorghum and sunflower may be an effective management tool for the mid-Atlantic stink bug complex, including H. halys. Future research should address the appropriate size and placement of trap crop within the farm.