Beauveria bassiana is a common soil-borne fungus that occurs worldwide. It infects immatures and adults of many different insect species in the orders Lepidoptera (butterflies and moths), Coleoptera (beetles), Homoptera (aphids, leafhoppers, whiteflies), Hemiptera (true bugs), and Hymenoptera (ants, bees, wasps). Important ornamental pests that are susceptible to this fungus include whiteflies, thrips, aphids, spider mites, and Japanese beetles.
Infection usually occurs through the insect's skin. Fungal spores contact the target pest and secrete enzymes which attack and dissolve the cuticle. These spores then grow into the insect's body and use it as a nutrient source. Mortality results from a combination of desiccation and nutrient loss. However, because this is an insect pathogen, it will take some time to suppress the pest population.
Naturalis-O, a contact mycoinsecticide from Troy Biosciences Inc., was recently registered by the EPA for use in greenhouses, outdoor ornamental plantings, and plantscapes. Produced by a fermentation process, Naturalis-O contains B. bassiana strain JW-1. The product is formulated in a manner that allows the fungus to withstand ultra-violet light, temperature, and humidity extremes commonly encountered in greenhouses and field conditions. Thorough spray coverage is essential because fungal spores must contact the insect for infection to occur. Generally 3-5 applications are necessary before pests are adequately controlled. Some additional characteristics of Naturalis-O include a short (4 hour) Re-Entry Interval, 3-7 days of residual activity, and safety to most beneficials. It can be applied with both hydraulic and ultra-low volume equipment.
- Raymond A. Cloyd, Purdue University
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