Flint on Crops: Nematodes Can Lead to Seedling Disease

Cotton roots damaged by root-knot nematodes. Photo: Texas AgriLife Extension

Before I get into the subject of this article I must recognize the importance of the general rains we have received during the past few days. While there may be isolated areas that still have not been reached by these beneficial showers most of the area has received enough moisture to keep non-irrigated fields going and to save some of the costs associated with irrigation.

The most critical situations are those fields that had become too dry for planting, and early-planted corn that is entering the silk and tassel stage. There is no way to describe how valuable these rains have been to this entire region given the stage of crops and the economic conditions that exist this year.

This is especially surprising in that rain in June is a fairly unusual event in our area. We must recognize what a blessing this has been. The balance of the growing season may present other challenges but the arrival of rain at this time has been especially important for all forms of agriculture and forestry.

The subject I want to discuss is one that I have noticed to be particularly important this year in fields that have significant populations of nematodes, particularly those with reniform and rootknot populations.

Many of these fields have shown noticeably higher levels of seedling diseases that are caused by our common seedling disease causing organisms as well as others in some situations.

My experience with growers through the years has been that when seedling diseases show up in fields of cotton and soybeans as well as other crops there is little acceptance of the idea that the problem is the result of a combination of issues rather than just the disease organism alone. Sure, weather is a strong player along with soil type, cropping history, and tillage system.

The first thing that comes to mind when we see high levels of seedling disease may be that the seed treatment has failed to do its job and this is a definite issue as well.

However one of the most important contributing factors to the incidence of seedling disease, particularly in cotton, is the presence of nematodes which injure the developing root tissue and allow easy entry of the disease causing organisms.

This relationship of nematodes to the incidence of seedling disease is one that has not received much recognition through the years although you may see it occasionally mentioned in passing. I found a statement from the National Cotton Council in one of their recent articles but it was not stressed.

There has been good research linking these two parts of the disease complex but it has seldom been the focus of information for producers who need to appreciate the importance of managing nematodes not only through the use of good fungicide and nematicide chemistries but also crop rotation, cover crops, tillage management, equipment cleanliness and other issues.

We are familiar with the ultimate importance of managing nematodes, however very few producers sample their soils and actively monitor the presence of this part of their crop management system. I find that many producers have the idea that there are not good tools for their use in this part of their pest management program when this is not the case.

Herbicide Resistance Info

There is a very strong need for educational programming about the importance of understanding the entire scope of plant diseases from nematodes and seedling diseases through the season as the differing parts fit together to influence not only seedling diseases but also other issues such as the wilt diseases in cotton as well as stem canker, SDS, charcoal rot and others in soybeans.

All the parts fit together to form the disease complex that can lead to success or failure with crops.

This is also true for other crops, especially the many horticultural crops that are grown both commercially and by home gardeners.

Thanks for your time.

The Latest

Send press releases to Ernst@Agfax.com.

View All Events

Send press releases to Ernst@Agfax.com.

View All Events