Pepper (Capsicum annuum) Cultivar Response to Metolachlor in Three New Mexico Soils

Abstract

Field experiments in 1988, 1989, and 1990 evaluated the response of four pepper cultivars to PPI applications of metolachlor at Las Cruces and Artesia, New Mexico. Metolachlor at ≥ 2.2 kg ai ha–1in 1988 and 4.5 kg ha–1in 1990 reduced overall green pepper yields only in a Harkey very fine sandy loam soil at Artesia. Metolachlor at ≥ 2.2 kg ha–1reduced the yield of the jalapeno cultivar ‘TAM’ and at 4.5 kg ha–1reduced the yield of New Mexico cultivar ‘NM 6-4’ and a proprietary New Mexico cultivar in 1988. Metolachlor did not reduce the yield of any cultivar in 1989 or 1990. Metolachlor bioactivity on NM 6-4 pepper was similar in the three soils regardless of irrigation water source. Emergence of peppers was ranked Belen clay loam = Rakor loam > Harkey very fine sandy loam when the greenhouse temperature approximated field conditions. Under conditions where germination and emergence of peppers was reduced by an interaction between soil factors and temperature, further stand reduction due to metolachlor treatment caused yield reductions.