Fungus on Tap
to Fight Whiteflies, Other Pests
By Jan Suszkiw
August 5, 2003
Trouble is literally brewing for
silverleaf whiteflies, thrips, spider mites and other insect plant pests.
The trouble in question is a new fermentation procedure that the
Agricultural Research Service has
patented for mass-producing spores of the fungus Paecilomyces
fumosoroseus as a biological pesticide.
Microbiologist Mark Jackson developed the deep-tank liquid culture
fermentation procedure based on his fungal nutrition studies at ARS'
National Center for Agricultural
Utilization Research in Peoria, Ill. There, he combined the procedure with
a commercial collaborator's method of formulating the fungus' spores into an
air-dried powder that can be wetted and sprayed onto plants.
Whiteflies are a prime target because the sap-sucking insects are pests of
some 600 different kinds of plants, including cotton, tomato and poinsettia.
Infestations in these and other U.S. crops have caused multimillion-dollar
losses. Whiteflies can also cause harm by infecting plants with disease-causing
viruses and excreting honeydew, a sticky waste product that can gum up farm
Paecilomyces kills whiteflies by penetrating the pest's body to feed
and grow. New spores emerge to infect other whiteflies, sparing nonhost insects
as they spread. Despite Paecilomyces' appeal as a biological alternative
to chemically controlling the pest, past attempts to commercialize the fungus
have stumbled on high production costs, quality control problems and other
Jackson figures he has overcome them through innovations in how the fungus'
spores are cultured, formulated and made stable for long-term cold storage. He
also chose a spore form, called a blastospore, that is well-suited for use in
biopesticide preparations because it is highly infectious to whiteflies,
killing them within several days of contact.
Read more about this research in the August issue of Agricultural
ARS is the U.S. Department of
Agriculture's chief scientific research agency.