Induced increase of soft scale: Imbalance between scales and natural enemies on walnut trees in northern California results in scale population increases

Michelbacher, A; Hitchcock, S

Induced increase of soft scale: Imbalance between scales and natural enemies on walnut trees in northern California results in scale population increases

Authors

A. E. Michelbacher
Stephen Hitchcock

Authors Affiliations

A. E. Michelbacher is Professor of Entomology, University of California, Berkeley; Stephen Hitchcock is Research Assistant in Entomology, University of California, Berkeley.

Publication Information

Hilgardia 12(11):13-13. DOI:10.3733/ca.v012n11p13. November 1958.

PDF of full article, Cite this article

Abstract

The principal natural enemies of soft scales attacking walnut trees in northern California are small winged parasites easily killed by trace amounts of insecticides. If undisturbed, the parasites are able to maintain the scale population much below an economic level.

Also in this issue:

California dairy industry, 1975: Anticipated 80% expansion in state's population expected to change present balances between production and consumption

Planning public water projects: Economic principles involved in construction and operation have important bearing on over-all value of public projects

Weather pattern effect on corn: Relationship between weather extremes, silk distortion, and blanking in sweet corn indicated by Coachella Valley studies

Yellowing of garbanzo beans: Aphid-spread yellowing virus needs different control though visibly similar to Fusarium wilt caused by soil-borne fungus

Mechanical pruning for citrus: Hedging and topping machines effective in increasing yields and reducing pruning costs during four years of field tests

Sulfur deficiency widespread: Areas in 34 of California's 58 counties found to have soils deficient in nutrient essential for normal growth of plants

Factors in prune skin texture: Marked skin toughness of dehydrated prunes investigated in effort to identify probable cause of the texture problem

Sweeter ice cream preferred: Study indicates consumers prefer ice cream with higher sugar content than the 15% level usually considered to be optimum

The rôle of surface tension and contact angle in the performance of spray liquids