Great Bend Tribune
Published August 27, 2017
The weather recently provided moisture and more moderate temperatures. Good for finishing off summer row crops, except needing heat to move corn and milo to the finish line, and for those looking forward to planting the 2018 wheat crop in a few weeks. There is one added benefit that many may over look – controlling the green bridge.
If you produce crops, you are likely aware of what a green bridge is, but just in case, let’s briefly explain. A green bridge is a term used in the disease and insect management of cultivated plants. It is termed a bridge since it spans the time between the crops you want for insects and diseases to survive and cross from the previous to the next crop. It is a “green” bridge since it consists of green plants that serve as an alternate host or habitat. Plant residue can also in some cases serve this purpose. And it doesn’t have to be in the exact field but for those pests that can move, it only need be close with close being several hundred feet to several miles. If the green bridge isn’t present it greatly reduces the likelihood of pest problems from certain, but certainly not all, pest pressure. By now you may know where this is leading – volunteer wheat.
Wheat Streak Mosaic Virus (WSMV) caused severe yield loss in many areas for the 2017 wheat harvest. WSMV is transmitted by the wheat curl mite. The mite feeds on an infected plant and takes up the virus. The mite then moves to an uninfected plant and when it feeds transmits the virus to the plant. Control is simple and yet challenging at the same time – control volunteer wheat for at least two weeks prior to planting the new crop and for a distance of about two miles from the field. That distance is about as far as the tiny mite can reasonably travel. It is simple as volunteer wheat can be controlled through tillage, chemically or a combination of both. In one sentence, volunteer wheat is wheat that didn’t make it into the combine bin for one of several reasons and all fields, no matter how careful the harvest will have some seed that falls onto the ground.
Control is difficult for several reasons. First, the volunteer wheat may not be in fields under your control and there is no rule or regulation making your neighbor control it. Second, weather may make controlling it in a timely fashion difficult. Third, the timing of volunteer wheat emergence isn’t predictable. If you till soon after wheat harvest and there is soil moisture, it will emerge, at least the first flush, in plenty of time to control. However, if the soil is dry or you don’t till and the seed is lying on top of the ground and it doesn’t rain, the seed won’t germinate. If dry conditions continue, you won’t have to deal with volunteer. What often happens is that late August/early September, we receive rain and the volunteer emerges late, often within two weeks of when you want to plant. That naturally presents a challenge.
This year Mother Nature cooperated and these recent rains have germinated the wheat, provided moisture for planting, and allowed adequate time for control. If you drive around the countryside you will see 2017 wheat fields starting to look like green carpets, the volunteer wheat that needs control. You will also see fields that have been tilled to control the volunteer.
This year to help prevent the disaster experienced by many producers in 2017, K-State, KDA, and many other farm groups have and are making a concerted effort to educate producers on volunteer wheat control. And as a warning, if education for volunteer wheat control isn’t effective, something less voluntary may be considered or lawsuits filed.