Cotton producers have had varieties that were tolerant of root-knot nematodes for several years. Beginning in 2014, Phytogen Cotton will be offering a variety – Phytogen 427 WRF – that has demonstrated resistance to the underground pests. Phytogen’s Steve Brown talked about the new variety and where it may fit in Southeast cotton production at the Sunbelt Expo in Moultrie, Ga.
Brown says growers have been able to plant Phytogen 367 WRF, a variety with tolerance to root-knot nematode. But Phytogen 427 represents a step change for growers who have seen drastic yield reductions from galling caused by root-knot nematodes feeding on the roots of non-tolerant varieties. Field trials show RKN populations being reduced to the low teens compared to 1,000 to 1,200 in a sample of soil with Phytogen 427.
From 70 to 80 percent of Georgia’s cotton fields are infested with root-knot and about 50 percent of those have infestations above the treatment threshold of 100 root-knot nematodes per 100 ccs of soil. “Root-knot nematodes tend to be more of a problem on sandier soils,” says Brown. “We have some variable rate technology where chemical controls are applied primarily to sandier areas of the field.
Cotton growers were able to keep root-knot nematodes at bay for years with applications of Temik. After Temik was taken off the market, root-knot nematode populations have been building to treatment levels in fields across the Southeast, often exceeding more than 1,000 nematodes per sample. Researchers have seen such large reductions with Phytogen 427 they believe growers may be able to use the cotton as a rotation crop with other varieties in the future.
A limited supply of seed of Phytogen 427 will be available in 2014, says Brown. Growers with moderate levels of root-knot nematodes can still plant Phytogen 367 and see a reduction in nematodes until more seed of Phytogen 427 becomes available.