Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 17, 1996
Publication Date: N/A
Interpretive Summary: Irish potato and sweet potato are grown on the same land in one year in the southeastern United States. Both crops are hosts of numerous nematode species. Additional crop rotations are needed to reduce nematode damage on potatoes. The objective of this experiment was to determine the effects of a nematicide and Irish potato-sweet potato grown continuously and in rotation with peanut-grain sorghum on nematodes, yield, and crop quality. Most crop yields were higher and root and tuber damage lower from nematicide-treated plots than untreated plots. The declining yields of Irish potato and sweet potato in both cropping systems indicate that these rotations should not be used longer than 3 years in soil infested with mixed species of root-knot nematodes.
Technical Abstract: The objective of this experiment was to determine the effects of fenamiphos and Irish potato (IP)-sweet potato (SP) grown continuously and in rotation with peanut (P)-grain sorghum (GS) on nematode population densities, yield, and crop quality. Greater root-gall indices and damage occurred on Irish potato than other crops. Most crop yields were higher and root-gall indices lower from fenamiphos-treated plots than untreated plots. The total yield of Irish potato in the IP-SP and IP-SP-P-GS sequences increased from 1983 to 1985 and decreased in 1987. The total yields of sweet potato in the IP-SP-P-GS sequence were similar in 1983 and 1985, and declined each year in the IP-SP sequence. Yield of peanut from soil infested with M. hapla was increased 82% in fenamiphos-treated plots compared to untreated plots. Fenamiphos treatment increased yield of grain sorghum from 5 to 45% over untreated controls. The declining yields of Irish potato and sweet potato indicate that the IP-SP sequence should not be use longer than 3 years in soil infested with M. incognita, M. arenaria, or M. hapla, a rotation including Irish potato or peanut should be avoided when these crops follow susceptible crops.