As we prepare land for fumigation and planting of new peach orchards we need to talk about nematodes. Often times in agriculture we have areas of a field or an orchard that do not perform as well as the surrounding land. This could be due to poor drainage, different soil types or other factors that are easily explained. There are however some areas where we do not have a good idea of what is causing poor crop performance. These areas may be suffering due to nematodes.
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. The nematodes of most concern in peach are the ring and root knot and root lesion nematodes. These nematodes cause poor performance and can predispose trees to other problems. Nematodes are usually more problematic on our sandier sites. So as we move into the heavier soils of the Piedmont and Upper Coastal Plain we see fewer problems.
Taking a nematode sample prior to planting can help determine if fumigation of the site would be beneficial. Two samples should be taken to best determine parasitic nematode levels, especially if the site is an existing orchard that will be removed and replanted. The first sample should be taken in late winter to early spring (Feb. – Apr.). This sample is primarily for ring nematode, which should be at their highest levels then. The second sample is taken in early fall (Sept. – Oct.) for root lesion and root-knot nematodes.
Nematode sampling prior to replanting an orchard can help determine if fumigation is necessary. Sampling existing orchards can help explain problem areas in an orchard, and the results can be used when scheduling pruning and planning use of the land when the current orchard is removed.