Hello All,
Just ran across an associated press story I thought would be of general interest
to the pollinators on line..
 
   WASHINGTON (AP) -- A natural fungus could help growers of melons, cucumbers,
tomatoes and other vegetables control infestations of whiteflies and use less
chemical insecticide.
   In field tests, the fungus has performed as well or better than chemicals,
according to Raymond I. Carruthers, a scientist with the Agriculture
Department's research service in Weslaco, Texas.
   The fungus consistently reduced numbers of immature whiteflies by 80 percent
to 90 percent in small field plots of cantaloupe, cucumber and tomato, he said.
   "We think most growers may need to use insecticide to knock down the first
whitefly populations infesting spring-planted melons and other vegetables,"
Carruthers said. "Then they would spray just the fungus about every week or so,
depending on how severe the infestation is."
   Whiteflies can cause huge crop losses. They have done their worst damage in
Arizona, California, Florida and Texas. In California's Imperial Valley,
officials estimate that whiteflies caused annual losses averaging $320 million
and more than 5,000 jobs from 1991 through 1993, according to an article in the
May issue of Agricultural Research, a USDA publication.
   Work on the fungus began in 1992 under a cooperative research and development
agreement between USDA's Agricultural Research Service and Mycotech Corp. of
Butte, Mont., according to the article.
   After evaluating 40 strains of fungus, field tests pointed to a Mycotech
strain of Beauveria bassiana as the most promising first candidate for
commercial production.
   Mycotech plans to market the strain in a wettable powder as Mycotrol-WP. The
Environmental Protection Agency approved its commercial use in March. Supplies
will be limited until a larger production plant begins operations next year,
Mycotech Vice President Clifford Bradley said.
   The fungus is sprayed on fields in a solution that includes a wetting agent
that helps fungus spores stick to leaves. When spores touch an immature
whitefly, or nymph, they germinate and release natural chemicals that bore holes
through the nymph's skin, or cuticle. Enzymes from the invading fungus dissolve
the fly's fat reserves. Within days, the nymph weakens and dies.
   Larger field tests are planned this year in Arizona, California and Texas to
refine integrated pest management strategies and allow farmers to get the most
benefit from fungus applications and reduce insecticide use.
   One of the remaining questions is the effect the fungus has on natural
populations of whitefly enemies like parasitic wasps.
   "So far, small field studies at Weslaco show the fungus has little effect on
field populations of biocontrol insects," Carruthers said. "We'll examine this
more closely."