The District has published numerous articles based on their research and experience.
Cross Resistance in Spinosad
J. Med. Entomol. 51(2): 428‹435 (2014); DOI: http://dx.doi.org/10.1603/ME13207
ABSTRACT A Culex quinquefasciatus Say colony was selected for 45 generations at LC70‹90 levels using Natular XRG, a granular formulation of 2.5% spinosad for induction of spinosad resistance. Resistance to spinosad was noticed in early generations (F1‹F9). Resistance levels increased gradually from generations F11‹F35, and elevated signiﬁcantly from generation F37 through F47, when resistance ratios reached 2,845‹2,907-fold at LC50 and 11,948‹22,928-fold at LC90. The spinosad-resistant Cx. quinquefasciatus colony was found not to be cross-resistant to Bacillus thuringiensis israelensis (Bti), a combination of Bti and Bacillus sphaericus, methoprene, pyriproxyfen, dißubenzuron, novaluron, temephos, or imidacloprid. However, it showed various levels of cross-resistance to B. sphaericus, spinetoram, abamectin, and ﬁpronil. Conversely, a laboratory colony of Cx. quinquefasciatus that is highly resistant to B. sphaericus did not show cross-resistance to spinosad and spinetoram. Fieldcollected and laboratory-selected Cx. quinquefasciatus that showed low to moderate resistance to methoprene did not show cross-resistance to spinosad and spinetoram. Mechanisms of cross-resistance among several biorational pesticides were discussed according to their modes of actions.
Optimization of EVS traps at West Valley MVCD
ABSTRACT: Encephalitis Virus Surveillance (EVS) Traps play an important role in mosquito and arbovirus surveillance. Mosquito control agencies frequently fabricate EVS traps in-house with components from various sources. Designs may also differ slightly from agency to agency. Inspired by Dever-NW traps, we initiated studies to improve our current EVS traps. We examined several key components with the intention to optimize functionality and efficiency of the traps, reduce daily operating costs and be more environmentally friendly.
Are fly maggots useful for West Nile virus testing in dead crow carcasses?
The testing of dead birds is a reliable surveillance tool for monitoring the enzootic and epizootic activity of West Nile virus (WNV). Fresh specimens, i.e., birds dead less than 24 h, are preferred for WNV antigen testing by VecTest® , RAMP® test, or viral RNA testing by real-time RT-PCR (rRT-PCR) and badly decomposed or scavenged carcasses are thought to be of limited diagnostic value. Signs that a bird has been dead longer than 24 to 48 h are the presence of maggots, extremely light weight, missing eyes, skin discoloration, skin or feathers that rub off easily, strong odor, or a soft, mushy carcass (California Department of Public Health 2008).