Low-Pressure Trunk Injection of Dicrotophos and Solubilized Benomyl for Pest Control on Mature Pecan Trees

Abstract

Injection of the trunks of mature pecan trees with dicrotophos was an effective method for controlling certain foliar pecan arthropod pests in urban plantings where conventional spray equipment is prohibited. Dicrotophos controlled yellow pecan aphids, Monelliopsis nigropunctata (Granovsky) and Monellia caryella (Fitch), when injected once at 1.9g (AI)/15 cm circumference (circ) of scaffold limb or twice at 0.96 g (AI)/15 cm circ. Dicrotophos controlled black pecan aphid, Tinocallis caryaefoliae (Davis), populations when injected once at 3.8 g (AI)/15cm circ or twice at 0.96 g (AI)/15 cm. Injection of the pecan trees with solubilized benomyl reduced pecan scab damage when injected once at 28 g (AI)/15cm circ or twice at 14g (AI)/15 cm circ. Pecan leaf scorch mite, Eotetranychus hicoriae (McGregor), populations were higher in trees treated with benomyl at 28 g (AI)/15 cm circ than in trees treated twice with benomylat 28g (AI)/15 cm circ plus dicrotophos at 1.9g (AI)/15 cm circ, whereas a single injection of dicrotophos and benomylat these rates did not control pecan leaf scorch mites. No chemical residues of dicrotophos were found in pecan fruits at harvest.