The reniform nematode is one of the most commonly found pests of cotton, with the ability to cause severe economic damage. In order to assess exactly how much damage the reniform nematode can cause, Auburn University plant pathologists conducted a field trial comparing a clean field to a reniform-infested field.
To get the most accurate data, the plant pathologists began with one field experiencing the same conditions, including soil type and irrigation system. They then split the field in half, leaving a 10-foot grass strip in the center, and inoculated one side with the reniform nematode and left the other half clean.
They planted 10 cotton varieties on each half. Averaged over two years, they found cotton yields were 50% lower in the reniform field compared to the clean field.
They also experimented with the nematicide Velum Total and found it to be effective, depending on the environment. The nematicide supported a 55% increase in yield in 2017 but only 6% in 2018, in part due to the dry spring.
The 2018 yields of treated versus untreated were not statistically different.
“This trial is unique because we can test varieties and nematicides with and without the reniform nematode under almost identical conditions in the field. We can truly measure the reniform nematode effect on yield and the real benefit of the nematicide,” said Kathy Lawrence, one of the plant pathologists involved in the study.
Lawrence advises growers to be careful not to allow the reniform nematode to establish in their fields. If they do discover nematodes, they should wash their equipment before moving to a clean field to prevent transfer.
To learn more about this study, read “Yield Loss of Cotton Cultivars Due to Rotylenchulus reniformis and the Added Benefit of a Nematicide” in the May issue of Plant Health Progress.
The American Phytopathological Society contributed this article.