Pest Problems
There are not many pests that affect buckwheat, and there is no remedy for those that do.
Animals
Deer and turkey are fond of buckwheat and are the biggest problem. Deer can be quite damaging when they feed in fields of young plants or ripened grain.
Weeds
Summer-sown buckwheat grows fast enough to smother weed seedlings. It is the most effective summer smother cover-crop, and is used by many growers as part of their overall weed management program.
Cool or wet weather can result in weed problems when the buckwheat gets off to a slow start. Excessive nitrogen will encourage the weeds more than it does the buckwheat, and weeds can be severe.
Buckwheat is very sensitive to many herbicides, and no broadleaf herbicides are registered. The only labeled herbicide is Poast for grass management (since 2006), whose principal use is controlling volunteer wheat.
Diseases
Diseases are often seen but are seldom serious problems for buckwheat production in the Northeast.
Aster yellows makes the flowers sterile and green. In affected fields, it is rarely more than 1 plant in 1000.
Powdery mildew is a seed-borne disease that causes yellow-green blotches on the leaves. This disease grows inside the leaf, not on the surface. It is not a serious problem, and is controlled by planting seeds from uninfested fields.
Sclerotinia stem rot is occasionally seen late in the season if the plant population is high and the stems are thin. It causes the plants to fall down. Immediate harvest is the only remedy.
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Insects
The insects that are seen (wireworms and aphids) usually do little damage in summer-sown buckwheat. Buckwheat that emerges in May, whether volunteers or an early cover crop, is at some risk of aphid infestation. Early aphids attract ladybeetles that protect later crops. Buckwheat attracts many other beneficial insects once it begins to flower, so it may even reduce the insect pressure nearby.