Re: Entomopathogenic Fungi--Metarhizium anisopliae There are a couple of aspect s of Metarhizium anisopliae (& the group of entomopathogenic fungi--a group of fungi found to infect insects) not spelled out in Dee's list of articles. Different strains have varying virulence against different families of insects (lepidoptera, coleoptera, hymenoptera, etc. Second these fungi are often very effective in a controlled setting but can have variable response because of changing environmental conditions during field evaaluation which makes it a challenge for commercial development. Lets start with strains--My guess is that the Metarhizium anisopliae strain selected for mite control has very little effect on honeybee's. Same species ( as far as scientist can tell) but different strains have a profoundly differing effect on differing families of insect. For example I'm currently working with a strain of entomopathogenic fungi that is very effective on a beetle, quite effective on a moth but will not touch a looper. Go figure! Genetic screening may lead to better information on why this is so. I can select (from the ARSEF culture collection, http://www.ppru.cornell.edu/mycology/ARSEF_Culture_Collection.htm) strains that have been found on specific species of insects that are ineffective against others in the same family. This can be exploited, tested for in the lab, selected for. So the specific strain selected for mite control probably has little to no effect against the Honeybee. Number two--These fungi are very sensitive to environmental conditions, particularly temperature & relative humidity. Again laboratory screening & selection can fine tune final selection of a safe & effective strain to be commercially developed to target a specific insect (or mite in this case). Safety to concurrent non-target or beneficial insects is always done prior to roll out. You could not develop a product that is shown to kill what you are trying to protect. Sometimes the actual site of effect is the separator. For example, If a fungus only works at cool temperature, say 20 degrees, probably will not be a threat to a colony of bees where the internal temperature is well above that, in effect thermally neutralizing the fungus. However, one concern might be--but again this will be screened for, this strain must operate where the mites are which is in a hive at a fairly warm temperature (by fungal standards) and might be of concern if M. a. were to slightly infect honeybees. Overall these fungi are very family specific, very safe ( hey I've screened hundreds in the lab and never gotten sick) and I hope it works. We need a diversity of tools to help beekeepers. As I have seen it it looks like it would be great if it could be rolled out as a traditional biocontrol. By this I mean that the beekeeper could spread out the pathogen once and the fungus would remain present slowly killing mites ever after. However it would probably need to be an ameliorative release where spores would be spread periodically more like an insecticide--in this case a mycoinsecticide. However after a good number of years of working with entomopathogens leads me to a pragmatic view- If Metarhizium anisopliae can be developed as a control it will not be a silver bullet. It will be another tool in our arsenal. It may work well sometimes at others it may not. IT may be difficult to come by as a commercial product--many companies producing & selling fungal pathogens as registered control agents have not survived long ($$$) and finally there may be some dust--fungal spore contamination issues, pollen collectors may not want to dust, and there may be some weird microbial balance disruptions because once you add something to a biotic system things change. Mike Griggs http://bees.library.cornell.edu/ :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: -- Visit www.honeybeeworld.com/BEE-L for rules, FAQ and other info --- ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::