Carolyn Pickel

Parasitism of Lygus hesperus (Miridae) by Anaphes iole (Mymaridae) and Leiophron uniformis (Braconidae) in California strawberry

Abstract Augmentative releases of two parasitoids, Anaphes iole Girault and Leiophron uniformis (Gahan), were evaluated for control of Lygus hesperus Knight populations on strawberry. Small cages were used to evaluate a range of parasitoid release rates on known densities of L. hesperus eggs or nymphs. In addition, the number of ovipositions per female L. uniformis and the distribution of ovipositions per nymph were determined for two densities of L. hesperus nymphs. Parasitism levels reached 80% for A. iole and nearly 100% for L. uniformis , indicating that these parasitoids will search for and parasitize Lygus in strawberry. A. iole was successfully reared from Lygus eggs within strawberry plants. Thus this host plant does not appear to be a barrier to the development of augmentative biological control. The distribution of L. uniformis ovipositions per host did not vary consistently from random in response to either host or parasitoid density. Ovipositions per parasitoid did not change in response to parasitoid release rate if high numbers of nymphs (300 per cage) were present. When half this number of nymphs were exposed to the same parasitoid release rates, the number of ovipositions per parasitoid declined as parasitoid densities increased. This indicates that for L. uniformis the level of mutual interference is influenced by both host and parasitoid density, not parasitoid density alone.

Analysis of Permethrin (Cis- and Trans-Isomers) and Esfenvalerate on Almond Twigs and Effects of Residues on the Predator Mite Galendromus occidentalis (Acari: Phytoseiidae)

Abstract A gas chromatograph-electron capture detection method for analysis of permethrin (cis- and trans-isomers) and esfenvalerate on the surface of almond twigs is described. Permethrin and esfenvalerate were extracted from the substrate with a hexane sonication, Florisil solid phase extraction cleanup, and quantification by gas-liquid chromatography with electron capture detector with a megabore capillary column. The mean recoveries for all three analytes were 87% with a coefficient of variation <13% at fortification levels ranging from 50 to 1,000 ng for each analyte. The limit of detection was 14, 13, and 4 ng for cis-permethrin, trans-permethrin and esfenvalerate respectively for almond twigs. Field collected twig samples taken 7 mo after pesticide application were found to contain measurable bark surface residues. Bioassays using those twigs indicated significant mortality to the beneficial mite, Galendromus occidentalis Nesbitt.

Extending integrated pest management by public mandate: a case study from California.

Abstract This case study systematically analyzed the adoption, over a seven‐year period, of governmentally mandated integrated pest management (IPM) practices by brussels sprouts growers in California. Promotion of required IPM practices were complemented by research, technical assistance, and education carried out by Cooperative Extension and other resources. Information, infrastructure, and perceived risk factors that affected growers and their nonadoption of the IPM presence‐absence sampling procedures were investigated. Growers who were required to use the practices were compared with other growers in a three‐county area not required to use the research‐proven IPM methods. The shortcomings of a mandated strategy and associated factors are discussed, emphasizing the need to consider organizational and human elements when requiring new agricultural production practices and behaviors.