Rebecca A. Schmidt-Jeffris

Stethorus pusillus (Herbst) is a specialist predator of spider mites and is a key component of mite biological control in many cropping systems. In the Pacific Northwest (United States), S. pusillus is an established, introduced species that is commonly found in crops as a resident predator, but it is also released for augmentative biological control. Non-target effects of some insecticides and fungicides can disrupt biological control by S. pusillus, reducing its efficacy. In laboratory assays, we evaluated the susceptibility of S. pusillus to 25 different commercially available pesticides, including 4 fungicides and 21 insecticides/miticides, spanning 14 known modes of action. We assessed the effect of direct contact exposure on adult mortality of both diapausing and non-diapausing S. pusillus. We also evaluated the non-diapausing adults for sublethal effects (locomotion and predation). Broad-spectrum insecticides, including acetamiprid, thiamethoxam, abamectin, fenpyroximate, and cyantraniliprole, caused moderate to high mortality, while selective miticides, such as clofentezine, hexythiazox, acequinocyl, bifenazate, spirodiclofen, and cyflumetofen, were largely harmless to both diapausing and non-diapausing adults. Among the fungicides tested, copper hydroxide caused high mortality, while mancozeb, captan, and fluopyram + trifloxystrobin had no effects. These results provide a useful update on the pesticide susceptibility of this important predator, which can be used by growers to make judicious spray decisions.

DNA metabarcoding has become a relatively common tool for studying consumption of plants by arthropod herbivores and identifying pollen collected by pollinating insects. However, studies using molecular gut content analysis to detect pollen-feeding in generalist predators are exceedingly rare. Pollen-feeding is known to be important to the nutritional ecology of many generalist predators and is particularly well studied in phytoseiid mites. In apples, generalist phytoseiids such as Typhlodromus caudiglans Schuster (Mesostigmata: Phytoseiidae) and the stigmaeid predator, Zetzellia mali (Ewing) (Trombidiformes: Stigmaeidae), feed on both pest mites and pollen trapped on foliage. It is unknown whether these mites commonly pollen-feed or if they exhibit in-field preferences for pollen type. To detect likely pollen-feeding in these predatory mites, we sampled tree foliage and the ground cover (vacuum sampling) from an apple orchard for 9 weeks in 2019 and 2020, and plant DNA was detected through metabarcoded gut content analysis using the trnF and internal transcribed spacer 2 (ITS-2) regions. We detected DNA from 31 plant genera in our samples. Malus was the most common taxon, followed by Pinus, Brassica, Festuca, and Lactuca. Forty-six percent of phytoseiid and 34% of Z. mali samples were positive for non-Malus DNA. Changes in detection of several taxa (Pinus, Festuca, Hyoscyamus, Citrullus, Poa, and Solanum) throughout the monitoring period likely reflected temporal variation in pollen availability. Pollen availability may play a role in determining the composition of predatory mite communities. Metabarcoding to detect possible pollen-feeding has the potential to improve our understanding of the role of floral resources in conservation biological control.

European earwigs are predators of woolly apple aphid (Eriosoma lanigerum [Hausmann]) (Hemiptera: Aphididae) and pear psylla (Cacopsylla pyricola [Foerster]) (Hemiptera: Psyllidae), 2 pests that are difficult to control with insecticides. Standard orchard pesticide programs in the Pacific Northwest United States region can suppress European earwig populations to undetectable levels, and low dispersal precludes substantial natural European earwig population growth within a season when the resident population is low. Therefore, workshops were conducted to teach orchardists how to transport European earwigs (Forficula dentata F. = F. auricularia L. sensu lato) (Dermaptera: Forficulidae) for biocontrol of apple and pear pests. The workshops emphasized European earwig inoculation alongside transition to integrated spray programs. Most workshop attendees reported intent to conduct their own collection and transportation, but few did the next year. Calculations of materials and labor costs indicate the per acre expenses of European earwig transportation should not be a major barrier to adoption, but the technique requires special planning and training, and it is only useful in specific circumstances. Transportation guidelines, cost estimates, and survey data in this article could be used by researchers and managers to plan more effective European earwig research and applications.

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.

Pear psylla, Cacopsylla pyricola (Foërster), is the most economically harmful arthropod pest of pears in the Pacific Northwest (PNW). The phloem-feeding nymphs produce a sticky, sugar-based excrement called honeydew, which causes cosmetic fruit injury, tree stress, and inconvenience to orchard workers. Management of pear psylla has historically prioritized season-long spraying with insecticides that have substantial nontarget effects on natural enemies. However, control has been an ongoing challenge in many growing regions due to pear psylla’s resistance to insecticides, and natural enemies are virtually absent in orchards with aggressive pesticide programs near harvest, leading to rapid increases in pear psylla. Subsequently, excessive numbers of overwintering pear psylla create a regional overabundance of the pest the following spring. Integrated pest management (IPM) programs for pear psylla prevent this cycle with effective cultural tactics and insecticides that are minimally disruptive to natural enemies. Still, IPM adoption seems to be regionally variable. The major growing region of the Wenatchee Valley in Washington State has been reluctant to adopt IPM and, consequently, continues to struggle with pear psylla management. Other areas, such as Hood River, Oregon, and Okanogan, British Columbia, have made significant improvements in pear psylla management through the adoption of area-wide IPM. This review will provide an overview of pear psylla biology, pest status in the PNW, primary IPM tactics, and various elements that have either challenged or advanced the pear industry’s adoption of IPM.

On 29 January 2024, a beloved red monster asked a question that broke the internet: “How is everybody doing?” ( Elmo 2024). Elmo soon learned that many people were decidedly not okay. While the wave of responses from folks facing serious challenges was heartbreaking, it was also amazing to see other humans (and some Muppets) reach out to strangers with words of comfort. Science is often a “passion career.” We choose this path because we are excited, interested, and engaged. In short, we care, and we care deeply. This can lead to incredible breakthroughs, exceptionally dedicated teachers, and compassionate solutions to the world’s problems. It can also lead to late nights, unhealthy competition, and work environments inhospitable to anyone that does not fit a very particular mold. As underscored in “Burnout” (Student Stadia) and “Take it to the Limit” (Zyzzyva), there is inherent tension in maintaining the balance between pushing yourself to improve and pushing yourself too far. This balance is even more difficult to achieve for marginalized people, especially when adequate community supports are lacking. To pile on, the important (and incredibly undervalued) “service” work of science, which includes building and maintaining these supports, falls primarily back on these same groups of people ( Järvinen and Mik-Meyer 2024, Miller and Roska 2019).

I was recently listening to my favorite podcast (Ologies with Alie Ward), and there was a delightful episode on carcinology (the study of crabs). Alie’s guest (Adam Wall, Natural History Museum of Los Angeles) mentioned the pinch-force power of the coconut crab. Coconut crabs have measured pinch forces of up to 1,765 N, but the largest specimens might reach 3,300 N ( Oka eta al. 2016). This exceeds the bite force of most vertebrate predators (except alligators). I couldn’t help but wonder about the pinch power of insects and other (non-crabby) arthropods. Among the groups traditionally studied by entomologists, which have pincers? This topic seemed particularly appropriate for the spring issue, as many of you will be reading this around St. Patrick’s Day. There is a substantial religiopolitical history behind the use of green in the Irish independence movement. However, the “get pinched for not wearing green on St. Patrick’s Day” component is much more lighthearted (green makes you invisible to leprechauns, who are notorious pinchers) and is likely of American origin. Regardless, I couldn’t get the idea of arthropod pincers to release its grasp on my brain.