The reniform nematode (Rotylenchulus reniformis) is a pest of cotton (Gossypium hirsutum L.), occurring in 16% of all cotton fields in Florida. Management is by crop rotation, the use of nematicides, or a combination of both practices. Crop rotation is not an option for many growers because of the relatively low prices of other agronomic crops, leaving nematicides as the only viable pest-management option. The objective of this research was to determine the optimum application rate of each of the two nematicides (1,3-D and aldicarb) recommended for use in Florida’s cotton with respect to lint yield increase and economic return associated with the use of nematicides to improve lint yields (partial net return). Lint yields and partial net returns were evaluated on cotton grown in reniform nematode-infested loamy sand soils in northwestern Florida. Four separate test sites were selected. Varying application rates of the nematicides were tested at each site and compared with a non-treated check over a 3-yr period. Lint yields and partial net returns increased using either nematicide. Because of significantly higher chemical and application costs of 1,3-D, use of 1,3-D resulted in greater lint yield increases compared with aldicarb, but aldicarb yielded greater partial net returns when both chemicals were applied at their respective optimum rates. These data suggest growers need to evaluate nematicides for improving partial net returns and increasing lint yield.
