Cornell Cooperative Extension's Jeff Miller has found some problems when scouting CNY corn and soybean fields.  Aphids, white mold and eyespot have all been reported. Read more to get tips from Jeff on scouting your crops and what to do if you find trouble.

Soybean aphids

have been at low levels in local soybean fields since June. Within the last two weeks I have found a few fields over threshold. The economic threshold for soybeans is 1200/plant. When scouting, if the count hits 250 aphids per plant it’s important to re-scout in a few days. If the number is increasing and your beans are at a maturity that is earlier than full seed you should consider spraying an appropriate insecticide. This insect can double its numbers in two days and significantly impact your yield.

This isn’t an easy decision: most growers want to avoid applying an insecticide if they can, there may be friendly predatory insects in the field that will be impacted by the insecticide, there will be some trampling damage to some soybean plants by the sprayer. The grower has to weigh out the pros and cons and make a decision.

White mold

is being found in a few local soybean fields. One field I visited two weeks ago had approximately 1% of the plants infected at the time. Two weeks later about 30% of the field is infected. This information should be noted. A minimum of three years should pass before planting this field to soybeans again. Then, only with a soybean variety with high resistance to white mold. No-tilling this field will help reduce the number of white mold sclerotinia that survive, if no-tilling fits the growers cropping system. The grower can select to apply an appropriate fungicide at first flower of that following soybean crop. The only products that are available in our area for this disease are protectants and must be applied before the plants are infected.

Eyespot

a disease with small light circular spots surrounded by a darker ring, in most local corn fields. In the last week I have found a few fields with northern corn leaf blight, which has medium to large cigar shaped lesions. Growers should make a note of what fields are affected by these diseases. If corn will be planted in these fields the following season, growers should look for varieties with medium to high resistance to the disease.

It takes specialized equipment (high profile sprayers) to spray appropriate fungicides to control northern control northern corn leaf blight at the brown silk stage of corn and the expense can be prohibitive. It is more economical to consider rotation or plant a variety that is resistant to the disease.

SOURCE: Cornell Cooperative Extension - Jeff Miller

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