This spring, FMC Corporation is pro-moting the use of Furadan 4F applied post planting to corn as a preventive treatment for first generation European corn borers. Their promotion guarantees rootworm control and first generation European corn borer protection. I have reservations about the benefits of this use from both economic and integrated pest management per-spectives. My concerns are similar to those I expressed about the Pounce 3.2EC cutworm guarantee, discussed in the last issue of the ICM newsletter. The following discussion of my concerns concludes with acceptable alternatives from an integrated pest management perspective.

Concern #1. Preventive insecticide treatments. FMC suggests that Furadan 4F applied post plant for corn rootworms (normally May 15 to June 15) also will provide corn borer protection. Using a broad-spectrum, synthetic insecticide in the absence of an economically damaging corn borer population cannot be justified as a preventive treatment, especially if a rescue treatment provides better control.

Concern #2. Insecticide performance. Entomologists at the University of Nebraska evaluated the Furadan 4F treatment in 1993 and 1994. Each year, plots were sprayed on two dates. The earlier spray was timed to coincide with corn rootworm hatch, and the later spray was timed to match the natural occurrence of first generation corn borers. All plots were artificially infested with corn borer egg masses when wild moths normally lay eggs. Artificial infestation assured that all treatments had an equal number of corn borers. Insecticides were either broadcast or banded, and cultivated or not cultivated.

During 1993, Furadan, Counter, and Lorsban applied early post plant resulted in more corn borers per plant than when the insecticides were applied later, during the normal corn borer egg- laying dates. In 1994, similar results were seen: the early insecticide treatment resulted in more larvae per plant. In several insecticide treatments, there were more corn borers than in the untreated checks.

These data suggest that an early application of Furadan 4F applied post plant for corn rootworms may not reduce the European corn borer population, but might create a problem. The exact reasons that there were more corn borers in the early-sprayed plots are not known. Possibly many beneficial insects were killed, their populations had not yet recovered when the corn borers attacked the plants, and the chemical residue was not persistent enough to kill the corn borers.

Concern #3. Insecticide guarantee. FMC promotional material states that the guarantee reduces your risk in using a new application method to control two of the most important pests. The Nebraska data suggest that your risk from corn borer injury actually may increase. It is very important not to be lulled into a false sense of security by this guarantee. The guarantee is subject to the condition that the field must be scouted for insect injury. Spraying the field early in the season doesnt preclude the possibility of crop injury by insects.

The guarantee provides Pounce 1.5G to retreat the field if the corn borers exceed the economic threshold. But that means you apply insecticide twice, while if you had applied a corn rootworm insecticide at planting, the rescue Pounce treatment may not have been needed.

Concern #4. Field scouting. For the guarantee to be valid, you must check the field and determine if corn borer injury exceeds economic thresholds. Remember, the Furadan guarantee allows for the failure of the insecticide; you must scout the field, and monitor product performance.

The alternative. There is a better way to manage European corn borers than by applying an insecticide that may aggravate an insect infestation. Scout the fields for corn borers. This newsletter will issue reports when corn borers are found and provide information on how to scout and determine the economic threshold. Then you can scout the field, look for early signs of injury, and determine if the economic threshold has been reached. This allows you to apply insecticide when it is really needed and economically justified.

Using Furadan, or any other insecticide, as a preventive treatment in the absence of economically damaging (or potentially damaging) insect populations is irresponsible stewardship of the insecticide and goes against the principles of integrated pest management. Remember: use your insecticides wisely.