Paul A. Funk, USDA-ARS-Southwestern Cotton Ginning Research Laboratory, 300 E. College Dr., PO Box 578, Mesilla Park, NM 88047
New environmental laws may someday restrict defoliant chemical application. To prepare for this possible challenge experimental thermal defoliators were operated in California, New Mexico and Texas from 2002 through 2007. This paper summarizes findings from extensive trials in a variety of field conditions and cultivars. Physiological studies showed the efficacy of thermal defoliation and its impact on yield and harvest timing. Fiber quality studies indicated no damage to lint value. Entomological studies demonstrated reduced late season pest populations.