Corn needs 9 inches of moisture -- either from the soil or from rainfall -- from pollination to maturity to achieve maximum yield potential, says Joel Ransom, NDSU Extension agronomist.
"This means that in the days and weeks ahead, our late season crops are going to be largely reliant on new rainfall to carry them through to harvest ," he says. "With the forecast for more hot weather, late season crops are in dire need of rainfall if they are to escape significant yield losses. For the corn crop, the urgency of this is increased by the fact that most of the crop is not yet beyond the drought sensitive stage of silking to early grain filling."
White wheat heads
Wheat stem maggots were found in about 40% of the field in North Dakota surveyed recently.
About 6% of the heads in the fields appeared to be affected had turned white, a symptom commonly associated with maggot feeding.
But Marcia McMullen, NDSU Extension plant pathologist, says several other factors appear to be causing white heads in wheat this summer, including:
- Root rot in which the heads and the whole plant turn a silvery tan and roots pull easily from the soil, and the roots and crowns are discolored brown instead of being a healthy white or cream color
- Heat sterility caused by high temperatures, full sunlight, and hot winds – heads or plants may be white or tips of heads may be white and shriveled
- Fusarium head blight or scab which causes wheat head tissue to turn a pinkish white, or heads often have some green and some whitish spikelets – if whole head infected, stem right below head looks brownish to purple
- Barley yellow dwarf virus infections may cause whole plants and heads to turn prematurely.
- Herbicide spray or drift injuries also are causing prematurely white heads in which the majority of plant stays green but heads are white and occurring often in patches, "sprinkled" in an area, or in strips.
"This year, because of the unusual heat and dry conditions in many areas, there may be a number of factors working together causing white heads," McMullen says..
Source: NDSU Crop and Pest Report