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Three imported species of wasps—Praon palitans Muesebeck, Trioxys utilis Muesebeck and Aphelinus semiflavus Howard—parasites of the spotted alfalfa aphid, are abundant in southern California and are becoming established in northern California.

Year-round production of potatoes in California frequently necessitates the use of resting tubers as planting stock. However, resting tubers normally do not sprout for 1-4 months after harvest—depending on varietal characteristics—despite exposure to optimal environmental conditions.

Mature vines of seedless Black Corinth, Thompson Seedless, and seeded Zinfandel grape varieties were used in tests with gibberellin at Davis during 1957.

Variable conditions in the fruit growing areas of California make it difficult to project the results from evaluation tests in one area to another. As a consequence, field plots were established for the 1957 season in Bartlett pear orchards—in Sacramento, Solano, El Dorado, Lake, and Mendocino counties—for University personnel to evaluate spray materials under local conditions. As a correlative evaluation, spray chemicals used in codling moth and aphid control plots were checked for their effects on spider mites.

Damage to spinach by the crown mite—Tyrophagus dimidiatus (Hermann) — was first observed to be of economic importance during the spring of 1949 in the Santa Clara Valley. Since that outbreak the mite has caused periodic damage to fall and spring planted spinach in most areas, but is more destructive in the coastal growing regions.

Two sets of experimental plots in 15-year old Santa Rosa plum orchards—on Marianna rootstock—were laid out north of Arvin in 1951. Orchard A had 75 trees per acre and was on Foster loam. Orchard B had 90 trees per acre on Hesperia fine sandy loam.

Deficiency of micronutrients in avocado trees is often an important problem in southern California orchards.

Prescribed burning has been used successfully to manipulate brush in second-growth ponderosa pine to increase desirable plants; to kill mature brush plants; to kill brush seedlings and deplete the amount of seeds in the soil; and, at the same time, to prepare a better seedbed for pine seedling germination.

The following article is the third of a series of reports of a survey of characteristics of and services offered by retail grocery stores in five counties in California made cooperatively by the Department of Home Economics, University of California, and the United States Department of Agriculture under the authority of the Research and Marketing Act as part of Western Regional Research Project WM-26.