Outlook of pyrethroid insecticides for pest management in the Salinas Valley of California

Abstract

Vegetable and strawberry (Fragaria × ananassa Duchesne ex Rozier) pest management involves intensive use of insecticides. Recently, pyrethroid insecticide residues toxic to benthic organisms (e.g., Hyalella azteca Saussure) were detected in the surface water of the Salinas Valley, California, resulting in the establishment of a Total Maximum Daily Load level for bifenthrin, cypermethrin, and lambda-cyhalothrin. Three discussion sessions and surveys were conducted during grower meetings held in Salinas, California, in 2016, regarding integrated pest management and critical use patterns of pyrethroid insecticides. Survey results were filtered to include only responses from qualified participants involved in pest management decisions on lettuce (Lactuca sativa L.), celery (Apium graveolens var. dulce Mill.), spinach (Spinacia oleracea L.), Brassica crops, and strawberry. Results indicated that there were many important crop-specific pests that were currently being controlled by pyrethroids, for example, western tarnished plant bug, Lygus hesperus Knight (Hemiptera: Miridae); Bagrada hilaris (Burmeister) (Hemiptera: Pentatomidae); cabbage looper, Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae); and root maggots, Delia spp. (Diptera: Anthomyiidae). Participants suggested that the carbamate, methomyl, was the only effective alternative to pyrethroid insecticides for these pests. Although some lower risk controls may be useful on organic crops where there tends to be a higher tolerance for damage, lower risk controls will not be useful in conventional cropping systems until there is a higher tolerance for damage in the product. The survey indicated that insecticides selected for pest management were chosen based on cost, efficacy, low mammalian toxicity, and short reentry and preharvest intervals.