Brevipalpus californicus Mite Bioassay, 2018

Brevipalpus californicus (Banks) flat mites can be found on citrus fruit at the time of harvest and can be a species of export concern. We conducted laboratory experiments in Aug 2018 to determine the effects of eight registered miticides and a surfactant (BreakThru S240) on B. californicus. For each treatment, a 250-ml diluted solution was prepared using the label rate of the miticide or surfactant in 100 gpa and sprayed for 2–3 s onto a Valencia orange preinfested with 50 adult B. californicus. Infested fruits were held in a room maintained at 22 ± 2°C for 7 d and mortality was assessed by observing mites under a stereoscope. Mites showing the ability to move one body length upon prodding were counted as live. Percentage mortality data were arcsine (square root(x))-transformed and means were compared using the Fisher’s Protected LSD test after one-way ANOVA analysis. The experimental design was an RCB with five replications—each treatment was applied to one fruit/wk and the test was repeated weekly over a period of 5 wk.

All miticide treatments caused more than 50% mortality of B. californicus mites and caused significantly higher mortality compared with the water check (Table 1). Five miticides, namely, Agri-Mek SC, Nexter SC, Magister SC, Fujimite SC, Kanemite 15 SC, and Nealta resulted in significantly higher mortalities than Breakthru S240, Onager Optek, and Cinnerate (Table 1). Among the treatments, Cinnerate and Onager Optek were the least effective in controlling B. californicus.

This research was supported by the California Citrus Research Board and industry gifts of funding and pesticides.