Combination Sprays with Benzyladenine to Chemically Thin Spur-type `Delicious' Apples

BA, NAA, and carbaryl at 75, 6, and 600 mg·liter -1 , respectively, were applied alone or in combination to `Starkrimson Delicious' in 1989 and `Redspur Delicious' apples ( Malus domestica Borkh.) in 1990. BA was effective alone, but when combined with carbaryl it thinned excessively. Thinning failed when BA was combined with NAA because many seedless pygmy fruit were formed and they persisted until harvest. BA and carbaryl were more effective than NAA at increasing return bloom. Return bloom was more closely related to total seed count than to final set. BA improved flesh firmness at harvest and after cold storage. None of the treatments influenced the development of calcium-related storage disorders following air storage. Chemical names used: benzyladenine (BA); naphthaleneacetic acid (NAA).