Longevity of ultra-low-volume sprays of fipronil and malathion on cotton in Mexico
In 1996, fipronil and malathion residues were evaluated after four ultra-low-volume (ULV) spray applications in northeastern Tarnaulipas, Mexico. Sprays were applied at 0.88 L/ha. Fipronil was applied at 28 and 56 g A.I./ha and malathion at 840 g A.I./ha. Four applications were made beginning 23 May at four, five and six day intervals. Leaf surface residues of malathion accumulated with each application. Leaf surface residues of fipronil applied at both rates dissipated >90% after 2 to 4 d after all applications.