In 3-year trials with Citrus reticulata cv. Wilking on sour orange rootstock NAA at 200 or 400 p.p.m. applied 6 days before the onset of extremely hot weather promoted fruit drop and greatly enhanced fruit size without depressing yields. Under other conditions, however, NAA at 400 or 600 p.p.m. was ineffective. A new thinning agent, 1-( alpha -naphthaleneacetyl)-3,5 dimethyl-pyrozole (TH 656) at 160 p.p.m. also increased fruit size without affecting yield.
In 3-year trials with Citrus reticulata cv. Wilking on sour orange rootstock NAA at 200 or 400 p.p.m. applied 6 days before the onset of extremely hot weather promoted fruit drop and greatly enhanced fruit size without depressing yields. Under other conditions, however, NAA at 400 or 600 p.p.m. was ineffective. A new thinning agent, 1-( alpha -naphthaleneacetyl)-3,5 dimethyl-pyrozole (TH 656) at 160 p.p.m. also increased fruit size without affecting yield.