Six Tips to Ponder on Nematodes

Nematodes are a hidden enemy that can take a big bite out of cotton yields. Bob Kemerait, a Plant Pathology Professor at the University of Georgia, has been studying the tiny pests for years and has some key points to consider when managing nematodes. 

Here are his six top tips: 

1. Remember, when you close the furrow you have made the vast majority of the decisions you can make to protect your cotton crop from nematodes. Once the furrow is closed, the die is cast, and you watch from the “nematode sidelines” for the remainder of the growing season. Variety selection and nematicides are planting time decisions that can help address the problem. 
2. There is no substitute for soil sampling to understand both the species of plant-parasitic nematodes and the size of the population in a field. Optimum sampling time is late in the season, but before first frost when soil temperatures drop. Fields may be sampled in zones or sections for better clarity. At the very least, sampling should be conducted to account for changes in soil type, cropping history, or by areas where poor growth and reduced yields were detected.
3. When soil samples are collected during the season to diagnose for possible damage from nematodes, samples should be collected from “poor, symptomatic” areas and from “good, healthy” areas to compare the results.
4. Nematode-resistant varieties should be planted where appropriate and when possible. Nematode-resistant varieties not only reduce damage in the current season, but also reduce size of nematode populations going into the following season.
5. Nematicides should be selected that are appropriate for the population of plant-parasitic nematodes in a field. For example, fumigation with Telone II will be more cost-effective where larger populations occur, while seed-treatment nematicides are effective at much lower populations.  Products like AgLogic and Velum are most beneficial at moderate populations. 
6. There is no substitute for rotating fields to non-host crops (e.g. corn and cotton where reniform nematodes are problematic) to reduce the impact of plant-parasitic nematodes.