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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #253440
Title: Effect of mowing cotton stalks and preventing plant re-growth on post-harvest reproduction of Meloidogyne incognita

Author
item LU, PING - University Of Georgia
item Davis, Richard
item KEMERAIT, ROBERT - University Of Georgia

Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/16/2010
Publication Date: 2/11/2011
Citation: Lu, P., Davis, R.F., Kemerait, R.C. 2010. Effect of mowing cotton stalks and preventing plant re-growth on post-harvest reproduction of Meloidogyne incognita. Journal of Nematology. 42:96-100.

Interpretive Summary: The southern root-knot nematode is a major parasite of cotton in the US, and management tactics for this nematode attempt to minimize population levels. We compared three post-harvest practices for their ability to reduce the nematode population in the field, which should reduce the initial nematode population for the next year's crop. The three practices tested were 1) chemical defoliation before harvest plus cutting cotton stalks after harvest, 2) chemical defoliation plus applying an herbicide to kill plants prior to cutting the stalks, and 3) chemical defoliation without cutting stalks. Tests were conducted in both the greenhouse and in the field. The greenhouse experiment showed that root-knot nematode reproduction was significantly greater when stalks were not cut. Cutting stalks plus applying herbicide to kill cotton roots did not significantly reduce nematode reproduction compared to cutting stalks with no herbicide application. In field trials, cutting stalks reduced eggs and galling compared to defoliation without stalk cutting. In a greenhouse test which used soil from the field plots, plants grown in soil from the defoliation only treatment had greater gall ratings and egg counts than in the stalk cutting plus herbicide treatment. Therefore, we conclude that cutting cotton stalks immediately after harvest effectively reduces root-knot nematode reproduction, and may lead to a lower initial population density of this nematode in the following year.

Technical Abstract: The southern root-knot nematode (Meloidogyne incognita) is a major parasite of cotton in the US, and management tactics for this nematode attempt to minimize population levels. We compared three post-harvest practices for their ability to reduce the nematode population in the field, which should reduce the initial nematode population for the next year's crop. The three practices tested were 1) chemical defoliation before harvest plus cutting cotton stalks after harvest, 2) chemical defoliation plus applying an herbicide to kill plants prior to cutting the stalks, and 3) chemical defoliation without cutting stalks. Tests were conducted in both the greenhouse and in the field. The greenhouse experiment showed that root-knot nematode reproduction (measured by egg counts and gall rating index) was significantly greater when stalks were not cut. Cutting stalks plus applying herbicide to kill cotton roots did not significantly reduce nematode reproduction compared to cutting stalks with no herbicide application. In field trials, cutting stalks reduced eggs and galling compared to defoliation without stalk cutting. In a greenhouse bioassay which used soil from the field plots, plants grown in soil from the defoliation only treatment had greater gall ratings and egg counts than in the stalk cutting plus herbicide treatment. Therefore, we conclude that cutting cotton stalks immediately after harvest effectively reduces M. incognita reproduction, and may lead to a lower initial population density of this nematode in the following year.