The root-knot nematode (Meloidogyne incognita) is a serious pest of cotton (Gossypium hirsutum L.), occurring in 61% of all of Florida’s cotton fields. It can be managed 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 (1,3-dichloropropene) and aldicarb {2-methyl-2-(methylthio)propanal O-[(methylamino)carbonyl]oxime}-recommended for use in Florida 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 root-knot nematode-infested loamy sand soils in northwestern Florida at four separate test sites. Varying application rates of the nematicides were tested at each site and compared with a non-treated check. Both nematicides had numerically greater lint yields and partial net returns relative to the non-treated checks. Both lint yield and partial net return were increased more by 1,3-D than by aldicarb,. These data indicate the need for a grower to evaluate the use of nematicides for improving economic returns and increasing lint yield.
