* Alfalfa Weevil: Many growers made their first cutting of alfalfa early this year, which is recommended over insecticide applications when large numbers of alfalfa weevil have infested taller alfalfa. If larvae survive the cutting and lack of food for a few days, they could still be alive when regrowth begins and possibly start feeding on the new growth. Growers should scout their fields for possible feeding on the new growth and apply an insecticide if feeding is occurring.
* Black Cutworm: This pest is a more common problem this spring throughout the Midwest including Ohio. Because of late planting, cutworms might already be at damaging stages when corn starts to emerge. Growers need to pay extra attention in those fields conducive to cutworm problems, such as no-till and or weedy fields.
* Cereal Leaf Beetle on Wheat: Some wheat growers in Ohio have reported adult cereal leaf beetles in their fields along with larvae in large enough populations to potentially cause losses of up to 40% in both wheat and oats. With wheat nearing or reaching the flag leaf emergence and the boot stage, the crop is coming into the susceptible period where significant feeding on the flag leaf can cause a major reduction in yield.
Growers statewide should check their fields and those who spot an average of one larva per stem should treat their fields with insecticides, Hammond says.
While in previous years the threshold for economic loss was two larvae per stem or flag leaf, that number is now down to one larva per stem or flag leaf, he says. This is because the larvae feed heavily on the flag leaf at a time when it is critical to the growth of the wheat head and can cause losses.
More information on cereal leaf beetle and a list of labeled insecticides can be found here.
Organic cereal grain fields are also at risk from cereal leaf beetle damage. Entrust, which is an organically approved product, can be used to treat the insects.