CHEMICAL BLOSSOM THINNING AGENTS REDUCE CROP LOAD OF ´RISING STAR´ PEACH IN NEW YORK

Two relatively new peach blossom thinning agents, Tergitol (TMN-6) and Entry, were evaluated along with Wilthin®, ammonium thiosulfate (ATS), soybean oil, and lime sulfur for chemical thinning efficacy in 2004 and 2005 in Appleton, NY. The studies were conducted in the field on five-year-old ‘Rising Star’ peach trees in on ‘Lovell’ rootstock in 2004 and on six-year-old ‘Redhaven’ peach trees on ‘Bailey’ rootstock in 2005. In both years, 5% ATS was the most effective thinner followed by Wilthin®, lime sulfur (4%), Entry® (3%) and Tergitol® (1.5%). ATS at 5% caused excessive thinning and reduced crop value while 3.5% ATS gave less thinning, and had the highest crop value.