I have been called out to look at several fields of wheat that have some serious disease problems and actually looked worse than most other wheat fields in the area.
I have been called out to look at several fields of wheat that have some serious disease problems and actually looked worse than most other wheat fields in the area. In each case, these fields were no-tilled into wheat stubble left over from the previous year. Each one of these fields had beans no-tilled into the standing stubble after wheat harvest and then wheat was drilled back into these fields last fall. All of these fields had a lot of wheat stubble from the previous wheat crop still visible on the soil surface.
In each case, the wheat looked really bad because of serious disease problems. Tan spot was the most prevalent disease noted. Serious cases of this disease is definitely related to continuous cropping of wheat. One field had symptoms resembling wheat streak mosaic which is a virus disease that occurs most commonly in western Kansas. It is spread by the wheat curl mite that survives the summer on volunteer wheat. So double cropping wheat into old wheat stubble is a very effective means of perpetuating this mite with the high risk of the virus infection. I have sent a sample of this wheat to the plant pathology lab in Manhattan to determine just exactly what disease is causing these symptoms.
Two other serious diseases associated with this practice are cephalasporium stripe and take-all root rot. There are several other diseases that can be transferred when continuous cropping of wheat is practiced as well.
The point I am trying to make is that continuous cropping of wheat is not a good idea and no-tilling wheat on wheat is an even worse idea. The best way to avoid these troubles is through crop rotation. If you are forced to continuous crop wheat at least work the ground to get rid of the old stubble from the surface. Do not no-till wheat into wheat.
A lucky break
From a farmer’s point of view, the weather has been pretty brutal so far this year. All the rain has added up to a potential agricultural disaster in the making. Everything is late because of excessive rainfall and more rain will only make the problem worse.
However, in all of this chaotic mess, there is one little flicker of good that is related to weather but not really our weather here. During most rainy years like this one, wheat leaf rust has already done extensive damage to our local wheat crop. Though, we have had plenty of bad things happening to wheat this year, wheat leaf rust is not one of them. This is a really good thing since this disease normally has killed the flag leaf by this time. Since this disease is absence, much of the wheat still has a healthy flag leaf and this should improve yields to a certain extent.
Wheat leaf rust usually does not over-winter to any great degree in our area. The infection depends on disease spores blowing north from Texas in the spring. By this time these rust spores have caused serious infection in the wheat in our area. However, it has been very dry in the parts of Texas from which the disease spreads north, and this dry weather has prevented leaf rust from developing in these areas in Texas. The end result is very few spores blowing north this spring, thus, very low infection levels in our wheat.
There are plenty of other diseases showing up in wheat in the area, though. The main ones right now are speckled leaf blotch which is caused by a septoria fungus and head scab which is caused by fusarium. This head scab appears to be quite heavy in some fields and not so bad in others. The difference is due to stage of development when ideal conditions existed for this infection to establish itself. Those fields with free moisture on the heads for an extended period of time just as the wheat began to bloom are the ones with significant head scab. There will be significant loss of yield and serious reductions in wheat quality in badly infected fields.
It is now too late to spray wheat for fungus infections so from here on out mother nature is in complete control. Dry, cool weather like we have had during this past week is the kind of weather we need. However, the forecast is for more rain which will only make the situation worse.
There are large areas in some fields that have died and turned white. For the most part, this is due to too much wet weather and waterlogged soil. The wheat died in these areas because of oxygen deprivation due to standing water.
This all proves, once again, that wheat is not a wet weather crop.