The microscopic pest: How to handle plants with nematodes

Published 6:13 pm Friday, September 2, 2016

By Ty Torrance

Much of my time is spent trying to figure out what is wrong with certain agronomic crops, vegetables or fruit. Often, plants might look as if they are drought stressed. Sometimes they appear to be suffering from a nutrient deficiency. If this is the case, the solution would seem fairly simple, right? What if those same symptoms are caused by something other than lack of water or nutrients? There may be nematodes present.

Nematodes are thread-like microscopic worms that live in all habitats, especially soil and water. Most species are beneficial but some are harmful parasites of plants and animals. Plant-parasitic nematodes are characterized by having a needle like structure in the mouth called a stylet that, depending on the nematode species, is used to feed on different plant parts. Root feeding nematodes are common, but there are also nematodes that feed on stems, leaves and seeds. Thresholds have been established for all nematode species with regard to the crops we grow in the south.

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Plant-parasitic nematodes can cause significant economic damage to almost all vegetables, field crops, fruit trees, ornamentals and turf grass by reducing both yield and quality. Annual global yield loss caused by nematodes is $78- 80 billion with an estimated annual loss in the U.S. of $8 billion. Damage caused by nematodes may provide an infection site for other disease causing pathogens resulting in additional loss in crop quality and yield. Control of plant-parasitic nematodes is usually accomplished through the application of nematicides that can range from $75 – $200 per acre.

As I stated before, damage from these pests can initially appear as nutrient deficiency in the foliage and is often misdiagnosed. Root damage is a common symptom in plants due to feeding by plant-parasitic nematodes. Nutrients and water essential for proper plant growth may not be absorbed.

Detection and correct identification of nematode species is the first step in managing plant-parasitic nematodes. Timely sampling of soil and plants is an important step in implementing appropriate strategies for control and preventing economic damage. The specific strategy for managing plant-parasitic nematodes varies with the crop.

Now is a great time to sample for nematodes in all of our agronomic crops like soybeans, cotton, peanuts, and corn. Just like a soil sample, a nematode sample needs to be representative of the entire field, so take samples from multiple areas in the field. A nematode sample should be taken right around the root zone of the plant because that is where the highest concentration of nematodes will be. It is best to put the samples in a cooler until you can get them to our office.

If you have any questions or need our assistance, please give us a call at (229) 248-3033.