Fungal biocontrol of Acari

Mites and ticks are susceptible to pathogenic fungi, and there are opportun ities to exploit these micro-organisms for biological control. We have coll ated records of 58 species of fungi infecting at least 73 species of Acari, either naturally or in experiments. Fungal pathogens have been reported to kill representatives of all three orders of the Actinotrichida (the Astigm ata, Oribatida and Prostigmata) and the Ixodida and Mesostigmata in the Ana ctinotrichida. Most reports concern infections in the Prostigmata, particul arly in the families Tetranychidae and Eriophyidae. Two species of Acari-sp ecific pathogens-Hirsutella thompsonii and Neozygites floridana-are importa nt natural regulators of pestiferous eriophyoid and tetranychid mites respe ctively. Research has been done to understand the factors leading to epizoo tics of these fungi and to conserve and enhance natural pest control. Hirsu tella thompsonii was also developed as the commercial product Mycar for the control of eriophyoid mites on citrus, but was withdrawn from sale in the 1980s, despite some promising effects in the Weld. Beauveria bassiana, Meta rhizium anisopliae, Paecilomyces farinosus, Paecilomyces fumosoroseus and V erticillium lecanii infect ixodid ticks in nature, and B. bassiana and M. a nisopliae are being studied as biological control agents of cattle ticks in Africa and South America. Beauveria bassiana also has potential as a mycop esticide of the two-spotted spider mite, Tetranychus urticae. There is scop e to develop fungal biocontrol agents against a range of acarine pests, bot h as stand-alone treatments and for use in integrated pest management. Furt her research is required to clarify the taxonomic status of fungal pathogen s of Acari, to study their ecosystem function, and to develop efficient mas s production systems for species of Hirsutella and Neozygites.