Nematodes are microscopic worms that live in the soil. Only about a millimeter in length and thinner than a hair, nematodes are mostly helpful for plant growth. Soils in Frederick County typically contain on the order of 100 nematodes per teaspoon of soil, and undisturbed soils can have several times that number. There are many different varieties of nematodes in most soils. Some can be harmful to plants, but more are helpful.

As an example, a species of nematode deadly to the dogwood borer is employed in an organic insecticide for this destructive insect. This nematode can track down the borer while it’s in the dogwood, unlike other insecticides that the borer has to come into contact with before it bores into the tree. The pine nematode on the other hand often infests and kills red and Scotch pine trees in Frederick County. Both of these species of pine trees are more suited to a cooler northern climate and really don’t belong in our area.

Nematodes are considered parasites and can affect a number of different plants and other organisms. There is a complex balance of beneficial nematodes for control harmful bacteria, fungi, and larva of harmful plant pests. A small nematode population can allow pest organisms to become a problem, and too large a population can reduce beneficial microbes.

Nematode shown is about 3/100ths of an inch long and is shown with Nematode Egg.

Credit: - USDA ARS

Nematodes are grown and sold by many agricultural garden, and ornamental turf suppliers to control specific target pest groups. More than 200 species of pest insects that spend part of their lifecycle in the ground are susceptible to control by nematodes.

The stages of development of nematodes are important for pest control, with larval stages often best for controlling grubs and other insect pest larvae. The market for beneficial nematodes is helped by their hardiness. They can be stored at room temperatures for around 3 months and in cooler storage for up to 6 months. As a naturally occurring organic pest control agent, nematodes are not registered as pesticides, but they are hardy enough to survive application through sprayers, even when mixed with some pesticides.

Article by FCFCDB

Nature Notes for 9/18/2011