Smellmelon is becoming a problem weed in southern Texas and Louisiana cotton-producing areas. Experiments evaluating the density and duration of smellmelon competition are necessary for the recommendation of appropriate control practices to minimize yield loss. In 1999 and 2000, field experiments were initiated to determine the density, critical period of competition, and potential control measures for smellmelon in cotton. Although the degree of competition differed between the years, similar trends were observed with respect to smellmelon density. As few as 2 or 3 smellmelon plants 10 m⁻¹ row reduced yield at least 17% each year. When densities were increased to 5 or 10 plants 10 m⁻¹ row, yield reductions increased to at least 34%. Results from the duration of smellmelon competition in 1999 and 2000 indicated that cotton should remain smellmelon free for 1 to 7 wk after planting (WAP) and 2.5 to 6 WAP, respectively. Results from the control studies indicate that smellmelon size at application influences control. Early-season control strategies are necessary to reduce yield losses associated with smellmelon competition.

Nomenclature: Bromoxynil; fluometuron; glyphosate; MSMA; pyrithiobac; smellmelon, Cucumis melo var. dudaim Naud. CUMMD; cotton, Gossypium hirsutum L. ‘DPL 436 RR’.