Losses from drought stress are not always obvious. Increased insect pressure, nutrient deficiencies, and intense weed competition can all be complications from drought stress. The good news is that while we can’t fight a drought we can effectively deal with some of the secondary problems it creates.
Corn earworms are often worse in hot, dry years. The speed at which these caterpillars multiply depends largely on heat , and their survival rates depend partially on rainfall. Eggs of corn earworms develop faster in hot weather, and the larvae develop quickly when temperatures remain in the 90s.
Shortened life cycles of these pests create two problems. First, they may appear earlier in large numbers and attack crops that are normally not affected. For example. Group V soybeans planted early in many areas of the Mid Atlantic region often escape infestations altogether. However, when heat and drought stress delay blooming, and drive the insects to develop earlier, these same planting dates and maturity selections offer no protection.
This year many such fields will be sprayed twice for worms. To prevent unnecessary losses, scouting should begin earlier in dry years and should be supplemented with moth trap monitoring.
When crops fail to develop a canopy it is difficult to control weeds with standard herbicide programs. To further complicate matters, growers must be even more cautious not to injure crops during periods of heat and drought stress.
Herbicide choices which are gentle on crops are excellent tools in such periods, and an experienced consultant is invaluable.
Most crops will test deficient in some nutrient during a drought. Soil applied nutrients can become unavailable as soils dry out, and roots fail to develop properly.
Foliar products like feed grade urea can sometimes be used to bridge the gap until rains come. Foliar micronutrients and secondary nutrients are also valuable when nutrients in the soil are simply out of reach or unavailable.
Droughts will always take their toll, but often aggressive management can reduce the losses appreciably.