Palmolive® detergent controls apple, cherry, and grape powdery mildew

Abstract

Palmolive® detergent applied in water was compared with the standard fungicide treatment for control of powdery mildew on apple [Podosphaera leucotricha (Ell. & Ev.) E.S. Salmon], cherry [P. clandestina (Wall.:Fr.) Lév.], and grape [Erysiphe necator (Schw.) Burrill]. Initial tests in the greenhouse with apple and grape seedlings showed that Palmolive® was as effective as myclobutanil in preventing powdery mildew on leaves. In apple orchard trials conducted in 2004, 2005 and 2006 Palmolive® detergent prevented powdery mildew on leaves, but caused fruit russetting when used at a rate higher than 5 mL L-1 through the growing season. The 10 mL L-1 rate reduced foliar powdery mildew in an apple and cherry nursery and in Pinot noir grapes, but caused russetting on grape berries. Further studies to determine optimum rates and spray timing will be required before it can be used safely on grapes. Studies on activity of Palmolive® detergent on Cameo apple leaves showed that it had protectant, eradicant, and antisporulant properties comparable with myclobutanil if applied within 1 d before or after inoculation with P. leucotricha and had superior antisporulant properties when applied to 7-d-old lesions. Palmolive® detergent, if used appropriately, could be an important component of an IPM strategy for control of powdery mildew on apple, cherry, and grape because it presents very little risk for the development of fungicide resistance. Key words: Pest management, plant disease, orchard, vineyard