Posts Tagged 'Metarhizium'

Organic Methods Could Help Rescue Honeybees

Effects of pesticides on Apis mellifera, the European honeybee, is at the top of the agenda of the new California Apiary Board appointed by the Secretary of Food and Agriculture. With the spread of Colony Collapse Disorder (CCD), this is an extremely urgent matter to investigate. The nutritional health of the bees is also an obvious factor that might relate to CCD. This season being so dry (witness the extensive wildfires), there isn’t as much forage for the bees. Fewer summer wildflowers (and less pollen) decrease winter food reserves, which may contribute to bee die off. Corn and soybean pollen offer little nutrition for bees.

However, arthropod pests also decimate bees, probably more so when they are weakened by pesticide exposure and poor nutrition. Bee pests include varroa mites, tracheal/external mites, small hive beetles, wax moths, ants, and also other bees, wasps, bee lice, dragonflies, spiders, predatory bugs, cockroaches, earwigs and termites. As a hobby-beekeeper with an avid interest in biological pest control, I would like to recommend that the new Board look closer at the non-toxic biological controls that may protect bees from insect and mite pests. Here are some examples:

Varroa mites have been reduced with insect eating fungi (entomopathogenic). Tests by USDA with a particular strain of Metarhizium anisopliae, showed good reduction of the varroa mite with no apparent harm to the bees. Follow up studies were done with another strain that was not effective. The price for treating a hive looks like $1-$2 per hive which seems competitive for organic. Currently there is no commercial supply in US. There are producers in India that can ship to US. Production is simple on cooked rice. This fungus is used in huge quantities in North Africa to control the desert locust, and is called green muscle after the green fuzzy spores sprouting from the dead insects.

Conidiobolus coronatus is a gossamer, phantom fungus, quite unlike anything you have ever seen before. It eats a lot of soft-bodied insects but not bees (hymenoptera). It seems to be good at reducing varroa mite, hive beetle, wax moth and termite. This product is only developmental, not sold as a control. However, it is sold as an inoculant for the hive. Powdered sugar helps. A screened bottom board with a sticky plastic sheet traps mites for monitoring.

Tracheal Mite can be controlled with menthol or a combination of thymol, eucalyptus and menthol. Some trials with smoke from eucalyptus or citrus leaves showed promise for this strategy. Grease patties and powdered sugar work well. Some predator mite may be found that would live in the hive and feed on the pest mites – Hypoaspis was tried without good results.

The small hive beetle Athina tumida, North America’s newest bee keeping pest, was first discovered in Florida in the spring of 1998. The above fungi are possibilities for the larvae in the hive. The larvae drop to the soil to pupate where you can treat with insect eating nematodes, such as Heterorhabditis bacteriophora (Hb). This nematode is commonly used to control white grubs in lawns. A suspension of the nematodes is sprayed on the ground around the hive and watered in.

Wax moth larvae eat the comb in weak hives or stored frames. Trichogramma, a minute parasitic wasp lays its eggs in moth eggs and the wasp larva eats the moth egg. Bt (Bacillus thuringiensis), a bacteria that makes caterpillars sick, can be sprayed on comb before it is stored, though it is not currently registered for this use. Light traps can reduce the adult moths in storerooms.

Ants can be excluded (along with roaches, earwigs and termites) with water or oil traps on the legs of the hives. A bait of boric acid, sugar and water, placed in plastic bait stations around the hive, will be taken back to the colony where it will knock down the colony. AntPro is the best of the bait dispensers.

Roaches and earwigs are attracted to yeasty baits like beer into mechanical traps. Slug Saloon with powdered beer bait traps earwigs and sow bugs as well as slugs. To make a roach trap, coat the inside neck of a pint jar with petroleum jelly and bait with a small piece of white bread moistened with beer.

I would like to see organic protocols for beekeeping be a top priority, which is a big challenge with invading pests. Of course a well-designed hive, good forage, and supplemental feeding gives the bees a chance to take care of themselves. When pests and diseases show up, beekeepers need access to knowledge about natural, integrated treatments that don’t stress the bees. The appointment of the new bee board shows the importance for California agricultural of honeybees for pollinating, especially almonds. Do you have other angles on bee problems, tips, suggestions, or questions? I look forward to hearing from everyone interested in organic beekeeping.

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