Skip to main content
ARS Home » Midwest Area » Ames, Iowa » Corn Insects and Crop Genetics Research » Research » Publications at this Location » Publication #63076
Title: EFFECTS OF FERTILIZERS ON THE SURVIVAL OF BEAUVERIA BASSIANA

Author
item ROSIN, FAYE - IOWA STATE UNIVERSITY
item SHAPIRO, DAVID - IOWA STATE UNIVERSITY
item LEWIS, LESLIE

Submitted to: Journal of Invertebrate Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/3/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Beauveria bassiana is a fungus that kills pest insects including the black cutworm and European corn borer. It is readily found on crop residue and mixed with the soil. It remains in the soil from one crop season to the next. Research is being conducted to develop biologically intensive integrated pest management systems for insect pests of corn. Researchers are defining ways to maximize the effectiveness of naturally occurring control agents i.e., B. bassiana in a biointensive sustainable system. Therefore, the survival of B. bassiana was determined when the fungus was placed in soil with nitrogen containing fertilizers, i.e., fresh cow manure, composted cow manure and urea. Fresh cow manure was detrimental to the fungus, composted manure was beneficial (the amount of B. bassiana increased) and urea had no effect. These data indicate that B. bassiana will be compatible with sustainable agricultural practices if manure is stored prior to application.

Technical Abstract: Beauveria bassiana, an ubiquitous entomopathogenic fungus, persists in soil for long periods. It is then available to infect soil-dwelling insects and to spread in the ecosystem. Persistence of conidia however, may be reduced by various abiotic factors including nitrogenous compounds. Research was conducted to evaluate the effects of nitrogen containing fertilizers on the epersistence of B. bassiana in soil. The nitrogenous fertilizers were: 1. fresh cow manure, and 2. compost ("Fertilife, Compost and Manure", Hyponex, Marysville, OH), and 3. urea (45-0-0). The treatments were two rates of each fertilizer standardized among fertilizers to approximately 560 kg N/ha and 280 kg N/ha, and a control (unamended soil). Soil-fertilizer mixtures were moistened to field capacity (approximately -0.33 bars) and then autoclaved. After cooling, 0.1 g of B. bassiana formulation containing 1x103 CFU/g (diluted with sterile corn /grits) was added to each fertilizer-soil mixture and incubated at 25 deg. C for 7 days. Survival of B. bassiana was determined by plating on a selective agar. Soil containing fresh manure was detrimental to B. bassiana, whereas high rates of composted manure were beneficial. Urea had no significant affect on the fungus. Therefore, it seems that certain factors in manure that reduce survival of B. bassiana are lost during decomposition. The increase in CFUs in soil amended with compost relative to CFU's of the control may be explained by the ability of B. bassiana to exist as a saprophyte. Perhaps high rates of compost can increase the efficacy of B. bassiana as a biological control agent.