Calag Archive

Biological control of the olive scale—Parlatoria oleae (Colvée)—by a parasitic wasp imported to California, showed marked improvement in 1960 over 1956, when a previous survey was made.

An abnormal sprouting condition in potato tubers has been observed in California sporadically for the past 15 years. The disorder, termed spindling sprout or hair sprout, appears as weak, threadlike sprouts initiating from the eyes of apparently sound tubers. Spindling sprouts have been attributed to such varied causes as potato viruses, fungus infections, psyllid insects and adverse environmental conditions. Preliminary investigations have implicated the aster yellows virus as contributing to spindling sprout in California.

A microscopic eriophyid mite—Aceria tidipae (Keifer)—causes virus-like symptoms on garlic: a distorting, twisting, and yellow and light-green streaking of the leaves. Severe attacks of this mite occurred in several California localities in 1960.

Conservation of soil moisture by weed control is important in the vineyards of the non-irrigated coastal valleys of northern California where heavy cover crops grow during the winter rainy season. It is essential to completely remove the cover crop growth as soon as possible after the spring rains terminate.