Michael F. Schuster

Condensed tannins of cotton leaves

Abstract Some primitive races of cotton ( Gossypium hirsutum ) are almost immune to spider mites. These strains contain condensed tannins of about 20% of dry wt. The tannins accumulate in leaves and their concentration increases in successive leaves until about the 10th true leaf. The upper leaves maintain this quantity until early fall. The condensed tannins give a moderate astringency to the leaf, and are mixed polymers hydrolysing in acidic digests to 1 part cyanidin and 4 parts delphinidin.

BIOLOGICAL CONTROL OF RHODESGRASS SCALE BY AIRPLANE RELEASES OF AN INTRODUCED PARASITE OF LIMITED DISPERSING ABILITY

The rhodesgrass scale, Antonina gramini (Maskell), was first found in Texas in 1942 attacking rhodesgrass, Chloris gayana Kunth (Chada and Wood, 1960). Since that time this scale insect has been found infesting 94 species of grasses in North America (Chada and Wood, 1960; Schuster, 1967), some of which it affects severely. Introduction of the scale parasite, Neodusmetia sangwani (Rao), from India was made in 1959 (Dean et al., 1961). Evaluation of this parasite in Texas as a control agent for rhodesgrass scale was begun in 1961.