Herbivorous soil nematodes are microscopic parasitic pests that plague agriculture and home vegetable growers alike, infesting soil and destroying plant roots. (Yes, there are good soil nematodes but that’s another story…). Control of soil nematodes is difficult and both man-made and natural chemicals are used, but a new treatment uses good ol’ Bacillus thuringiensis, commonly found in caterpillar sprays, to new effect on nasty nematodes.
Those who grow lots of vegetables know all about crop rotation. Part of that is to replenish the soil, but it’s also to try and prevent infestations of soil nematodes which are attracted to plants in the Solanaceae family, like tomato, potato, eggplant and capsicum (peppers). The nematodes attack the plant roots, forming galls or ‘root knots’, giving the common name of root knot nematode. They quickly debilitate the plant, causing stunting and yellowing, and also carry viruses between plants. Once you’ve got nematodes, it’s very difficult to get rid of them.
Control and eradication methods include growing marigolds or Indian mustard (Brassica juncea), soil steaming, and a wide range of chemicals such as organophosphates.
Research over the past 10 years shows that Bacillus spp, such as Bacillus thuringiensis, a bacterium used in several insecticides to control caterpillars, can also be used very effectively against parasitic soil nematodes, providing a non-toxic biological control.
However it’s been difficult to develop an appropriate culture and then to get it to stick onto plant roots, but a USA-based company, OceanGrown Inc claims to have perfected the science in its new product Nemantor+. It claims that a nematode assay by the Florida Soil Laboratory found a 85% drop in nematode populations after treatment with Nemantor+.
Bayer has also applied for a patent on a culture of closely related Bacillus amyloliquefaciens for nematode control.