- Agronomic: corn
- Education and Training: on-farm/ranch research
- Pest Management: biological control, integrated pest management
[Note to online version: The report for this project includes tables that could not be included here. The regional SARE office will mail a hard copy of the entire report at your request. Just contact North Central SARE at (402) 472-7081 or firstname.lastname@example.org.]
The European corn borer (ECB), Ostrinia nubilalis is a serious pest of corn in the Corn Belt, causing estimated yield losses in the Midwest from $50 to $120 per hectare of corn (est. $20-$50/acre). With increasing restrictions on insecticides, the call for sustainable agriculture, federal mandates for less surface and ground water remediation and to have 70% of crop land under IPM by the year 2000, necessitates innovative methods to control this pest.
In 1996 and 1997, we conducted on-farm research, with cooperators from the Practical Farmers of Iowa (PFI), in a biointensive approach to managing this insect. In 1997, we also conducted research on an additional farm not affiliated with PFI. An entomogenous fungus Beauveria bassiana, that develops a unique endophytic relationship with the corn plant was employed in this management technique. In 1996, the fungus was applied to corn at the whorl stage, pollen-shedding stage and at post-harvest to manage the first generation, second generation, and overwintering ECB. In 1997 the fungus was applied only at the whorl stage of plant growth. In small field plots B. bassiana has been shown to reduce plant feeding during the growing season and B. bassiana present at harvest kills overwintering larvae, reducing the following year’s population. Once this fungus is placed in the ecosystem it will maintain itself in the soil, crop residue, and the growing corn plant. At this time in our research we do not know how often B. bassiana must be applied to the ecosystem to maintain the ECB below an economic threshold. If this scenario is practiced over a wide area it may be possible to maintain the ECB below an economic threshold without use of synthetic chemical insecticides. This approach may completely transform ECB management. Primary benefits of this proposed research are: (1) reduced producer dependency and exposure to synthetic insecticides, (2) less environmental contamination, and (3) a contribution to long-range goals of reduced environmental and ecological disruption from overuse of insecticides.
On farm research was conducted to evaluate Beauveria bassiana for season-long suppression of the European corn borer (ECB). A commercial preparation of B. bassiana, Myco 9701, Mycotech, Butte, MT, was applied to plants at 0.4 g/plant (ca. 2.2 x 1012 conidia per acre), with a hand-held inoculator. Treatments were applied to corn at whorl-stage (V7), pollen-shed stage corn (R1), to crop residue at post-harvest and corresponding untreated checks. In 1997, the treatments were B. bassiana applied only at whorl stage and an untreated check. Experimentation was conducted on three farms, Practical Farmers of Iowa (PFI) in 1996 and the same PFI Farms and an additional private farm in 1997.
Data were collected on number of cavities made by ECB larvae, tunneling by ECB larvae, number of plants with no apparent feeding by ECB larvae, number of larvae in a plant infected with B. bassiana and grain yield. In both years an application of B. bassiana to V7-stage corn caused reductions in the number of cavities, amount of tunneling and an increase in number of plants without ECB feeding. These statistically significant differences did not always occur at all locations. In 1997, there were also significant differences in reduced number of cavities, tunneling and an increase in non-damaged plants and a statistically significant increase in grain yield on one farm. B. bassiana had no significant affect on overwintering ECB when applied at post-harvest. Even though B. bassiana caused a reduction on insect damage, related increase in grain yield was apparent only in one trial in 1997. Yield, however, is dependent on many things in addition to insect damage. All yields except the latter were from small plot evaluations whereas the latter was taken from 1600 row ft per treatment replication. The large plot most likely reduced inherent variability. B. bassiana is indigenous, an environmentally friendly approach to ECB management and is maintained in the ecosystem.
1. Develop methods to use Beauveria bassiana for on-farm within season suppression of first and second generation European corn borer larvae.
2. Document that the use of B. bassiana in Objective 1 combined with a harvest application of B. bassiana for overwintering European corn borer larvae will provide multi-season suppression.