CONTROL OF PHYTOPHTHORA ROOT-ROT OF CHILE PEPPERS BY IRRIGATION PRACTICES AND FUNGICIDES

Field experiments were conducted to test the effects of alternate-row irrigation, every-row irrigation, and chemical treatments with alternate-row irrigation on yield of chile (chilli) peppers (Capsicum annuum) and disease incidence of chile pepper root rot caused by Phytophthora capsici. Field trials were conducted in 1989 and 1990 near Las Cruces, New Mexico. In 1989, chemical treatments were Telone C-17, metalaxyl, copper sulphate and metam-sodium; in 1990, chemical treatments were copper sulphate and metam-sodium. Disease incidence in plots receiving alternate-row irrigation without fungicides was significantly less than irrigation of every row without fungicides in 1989 and 1990. Disease incidence was also significantly less in the metam-sodium and metalaxyl plots than the every-row irrigated plots in 1989, but not significantly less than control plots irrigated with alternate rows without chemicals. Yield of red chile was significantly higher in plots treated wth metam-sodium and given alternate-row irrigation than all other treatments in 1989. Yield of green chile pepper from plots given alternate-row irrigation was significantly higher than plots given every-row irrigation in 1990. Metam-sodium with alternate-row irrigation was as good as, or better than, alternate-row irrigation alone in reducing disease incidence of P. capsici and in increasing yield.