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White heads in wheatKansas As wheat heads further towards maturity, there has been some question about why some plants, or entire areas of a field, seem to be maturing faster than others. In some cases, the answers are clear cut. In others, a little research is necessary. This year's top four are: --Drowning and other causes of premature dying. As wheat begins to mature, plants in some areas of the field may have an off-white color similar to take-all. This is premature dying, which could be due to drowning, sometimes hot dry weather, or some other stress, including soils that were waterlogged or damp enough that roots systems have remained shallow. The pattern of off-colored heads will often follow soil types or topography. The grain will be shriveled and have low test weight. --Freeze injury to stem or crown. Depending on the stage of growth at the time of a late spring freeze, parts or all of the heads may die and turn white. This is most often due this year to freeze injury to the lower stem, which then cuts off water and nutrients to the developing head. In years when the wheat is in the early heading stage at the time of the freeze, the freeze can damage the heads directly. --Head scab. This has been a big one this year. When there are periods of rainy weather while wheat is flowering, some heads may become infected with Fusarium head blight and turn white. The heads of some red-chaffed varieties, such as Overley, turn a darker red when infected with scab, but the heads of many varieties turn white. Often, only the upper half of the head is white. Head scab is most common where wheat is grown after corn, or after a wheat crop that had head scab the previous year. We have seen up to 10 percent scab in certain fields in central and eastern Kansas this year. Varieties in the District wheat plot ast Sabetha showed some variation but almost all had scab. --Take-all. This disease often causes patches of white heads scattered throughout the field. It occurs most frequently in continuous wheat, and where there is a moderate to high level of surface residue. To diagnose take-all, pull up a plant and scrape back the leaf sheaths at the base of a tiller. If the base of the tiller is shiny and either black or dark brown, it is take-all. All tillers on a plant infected with take-all will have white heads. Plants will pull up easily. --Wheat stem maggot. wheat stem maggot damage is common every year in Kansas, but rarely results in significant yield loss. It usually causes a single white head on a tiller, scattered more or less randomly through part or all of a field. If you can grab the head and pull the stem up easily just above the uppermost node, the tiller has probably been infested with wheat stem maggot. Its been an interesting year for wheat. Since harvest isn't here yet, there's still a chance to see some things that we haven't seen in awhile. The interesting year continues. Bagworm Control Window Bagworms are now feeding, in fact, they likely started back in May for most. By now, most are just about "in place" and if not controlled, they'll spend the next three months eating and building their own protective bag. So, even though you can't really see them, now through the end of the month is when controls are most effective. If you had them last year, it's likely you also have them this year. Check out your trees now, starting at the tops, looking for white tissue where green should be. The bags do blend in with surrounding tissue but they are visible now if you look closely. Control can be achieved via the use of various products. Check with your District Office for specific names. With any product, thorough coverage of all plant parts is essential. Date: 7/5/07
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