Microbial and nematode control of the bulb mite, Rhizoglyphus robini (Acari: Acaridae)
Abstract: The bulb mite, Rhizoglyphus robini, is serious pest of garlic, onion and many othercrops. Control of this pest has relied upon the use of synthetic acaricides and insecticides, butthis option is now limited mainly due to withdrawal of some chemical pesticides. Thus,alternative control methods, e. g. biological control, need to be developed and implemented.Besides using predatory mites, entomopathogenic fungi (EPF) and nematodes (EPN) might beperspective biocontrol agents against R. robini. The objectives of our study were to determinethe pathogenicity of selected strains of EPFs and EPNs to the bulb mite and evaluate theirpotential for its biological control. Twenty EPF strains (11 strains of the genus Metarhiziumsp., 5 strains of the genus Beauveria sp., 2 strains of the genus Isaria sp. and 2 strains of genusLecanicillium sp.) isolated from onions and garlic fields in Israel and the Czech Republic weretested against female R. robini females. Bulb mites were also exposed to the infected juvenilesof Steinernema and Heterorhabditis EPN species and mite mortality was assessed. The highestmortality (98-99%) was caused by Metarhizium sp. strains isolated from Kolence and Meziříčí(Czech Republic) and from Gazit (Israel). Both Steinernema and Heterorhabditis turned out tobe able to invade and kill bulb mites, but mortality reached the maximum of 30%. The mostefficient strains are now used in soil application experiments.