There can be no grazing of livestock on treated fields, and no feeding of forage hay, or silage from treated fields to livestock. For the past three years we have been running a developmental model, IPMP 2.0, for four major pests in peppermint. The models predict their life cycles and give recommended treatment times based on a historical weather file and current data for the year. It is recommended to control at this stage before they start laying eggs, roughly 10 days later. The adults can be sampled for by taking sweep nets in the evening a couple hours after sunset.
Early spring sampling for larvae is more effective by taking soil samples.
When threshold levels average 5.5 larvae per sample the adults should be treated. They start laying eggs towards the end of June and the 1st of July. Treatment is recommended for the 2nd and 4th instar stages the end of July. The models shows that they are beginning to exit the rhizome and will pupate by the end of the month, June 28th in Madras and the 30th in Powell Butte. No insecticides are registered to control mint flea beetle.