Sidelights on European Red Mite Control

Abstract

Sulfur dust, with lead arsenate concentrated in a mist spray, applied throughout the post-bloom period, promoted a severe infestation of Paratetranychus pilosus. The addition of chloroethyl butyl phenoxy methyl ethyl sulfite to the sulfur and lead arsenate did not give satisfactory control. Dinitro capryl phenyl crotonate with lead arsenate, applied throughout the post-bloom period, gave excellent control, but was somewhat less effective than sulfur for apple scarb control. Predaceous enemies, especially Stethorus punctillum, held the mite population to a low level on trees not treated after bloom, and on trees treated with lead arsenate only. Injury to apple foliage resulted from the combined effects of mite activity and spray injury, and was aggravated by high temp. Sulfur was more injurious than lead arsenate. The chlorophyll content of the leaves was a close index to the degree of injury to the foliage. There was a direct correlation between the chlorophyll content of the leaves, and the size, weight, color, and sugar content of the apples.