Cotton (Gossypium hirsutum) response was evaluated when quinclorac was applied prior to cotton emergence (preemergence) and to cotton in the cotyledon and pin-head square stages in 1988, 1989, and 1990. Quinclorac applications at 9, 17, 35, 70, and 140 g ha−1 prior to cotton emergence had little effect on cotton growth, with only 140 g ha−1 causing stand reduction or stunting. Quinclorac application to cotton in the cotyledon stage caused more damage, and 70 g ha−1 caused crop injury. Greatest phytotoxicity was observed when quinclorac was applied to cotton at pin-head square, with all rates including 9 g ha−1 causing injury. Cotton injury consisted of leaf strapping and malformation of reproductive structures. Regression analysis revealed yield was reduced by quinclorac applications to cotton in the cotyledon or pin-head square stage. The approximate regression equation to predict cotton yields after pin-head square application of quinclorac was [yield] = [yield with no injury] − 10(quinclorac rate in g ha−1).

During the 20th century, naturalized saltcedar has become common within major tributaries throughout the western United States. Often growing in nearly monocultural stands, saltcedar is suspected of lowering water tables, thus destroying wetlands and wildlife habitats. Management efforts have primarily relied on mechanical and cultural practices, but recent success in controlling saltcedar with imazapyr has led to wider herbicide use. Based on a number of research/extension field trials in New Mexico from 1987 to present, imazapyr applied alone or in combination with glyphosate was found to control saltcedar to levels of 90% or greater, especially when applied in August or September. For fixed-wing aircraft applications, we recommend applying imazapyr at 1.1 kg ai/ha or imazapyr plus glyphosate at 0.56 plus 0.56 kg/ha. For individual plant treatments, we recommend spraying the foliage to wet with imazapyr at 1% v/v in water, or imazapyr plus glyphosate at 0.5 plus 0.5% v/v. Herbicide activity may be reduced as saltcedar height and stem number increases.

Cotton response to triclopyr was evaluated when it was applied over-the-top at simulated drift rates to pin-head square and early bloom cotton growth stages in 1987 and 1988. The herbicidal effects of triclopyr were most evident after a lag period of 10 to 15 d. Triclopyr at 60 g ai ha-1 applied at pin-head square reduced cotton height in 1987, but not in 1988. Triclopyr applied at pin-head square and early bloom reduced cotton flowering initially, as measured by white bloom counts, in both years. Total blooms were reduced in 1987, but not in 1988. Cotton maturity was delayed by triclopyr application during early bloom, as shown by a decrease in percent open bolls, and a decrease in first pick cotton yields. Cotton yield was lower in plots receiving triclopyr, with the greatest yield reduction caused by a 60 g ha-1 triclopyr application at early bloom.