An apparatus designed to defoliate cotton with hot air was tested in two varieties and two field conditions. Cotton defoliation using hot air was as effective as defoliation using typical chemicals under some conditions. Aphid populations were eliminated by the thermal treatment, reducing the risk of producing sticky cotton. The trash content of cotton defoliated by thermal and conventional means were similar. Fiber properties were the same when compared to either chemical defoliation or no defoliation. Seed germination rates were also unchanged.