These symptoms are most often caused by frost or chilling. During cool, moist weather, growth is likely to be white or yellow and stunted in the low areas of the field where cold air tends to settle. The same areas are likely to have more vigorous growth in warm, dry spring weather. If areas in fields are observed during summer or early fall, pull some plants and examine them for root-knot galls.
Young plants wilt and fall over.
Another possible cause is the seedcorn maggot, which can be found feeding on the roots or inside the stems of young seedlings. Vines produce only male flowers. Cool temperature and excessive nitrogen may also be related to this problem. Usually the problem is temporary and will be resolved when lateral vines develop to produce female blooms with normal frequency. Such areas occur regularly in early spring and fall when the humidity is low.