Calag Archive

Over the last three years the Recreation and Parks Department of the City of Berkeley has worked with members of the Department of Entomological Sciences, University of California, Berkeley, to develop an integrated insect control program for the city's 30,000 street trees. The program has virtually eliminated synthetic chemical insecticides as regular management tools on the city's 123 species of shade trees. This program has resulted in lower pest management costs, fewer citizen complaints, elimination of secondary pest outbreaks and a reduction in environmental contamination. By reducing the amount of pesticides used, the city of Berkeley saves about $22,500 each year in labor and pesticide costs. The current program is a synthesis of various non-toxic management methods including biological, microbial, cultural, physical—along with the judicious use of chemical controls, when needed.

The depth at which asparagus crowns are placed in the soil or are direct-seeded varies in California between production areas and between growers in a single area. The influence of different seeding depths on asparagus production has not been clear. Some studies show that ridging increases yields. These studies do not specify the depth of soil cover over the plants, however.

Receivers in eastern markets occasionally complain that upon arrival, air-shipped California carnations appear “cooked” and ‘Forever Yours’ rosebuds have turned an unattractive blue. Neither species subsequently recover. Tests conducted during 1972 indicate that these problems are caused by poor packing practices, as well as handling procedures during transit.

ITALIAN THISTLE, Carduus pycnocephalus. L., and milk thistle, Silybum marianum (L.) Gaertn., alien weeds of Eurasian origin, have been studied since 1966 as targets of biological control in southern California. Found mainly in the coastal counties, these thistles are common weeds on grazing and pasture lands, open woodlands, fallow cropland, and wastelands such as roadsides, railroad rights-of-way, field margins, and ditch-banks. Field surveys from 1966 to 1971 established that both weeds were relatively free of deleterious insect injury. Most insects found associated with these weeds were sap- or foliage-feeding species which apparently had little influence on the vigor and reproductive capacity of these thistles in southern California.

Best control of chaparral shrubs on range-land at Hopland Field Station has been achieved with the use of herbicides. In both grazed and ungrazed areas, chemical control reduced the brush to less than 1% of the plant cover within four years and maintained a very low level for the 14-year period of the experiment. Grazing without other controls had little influence on the results, except for a re-occurrence of poison oak in ungrazed areas. Fire reduced the composition of brush for the first two years, but peaked out in the sixth year with a gradual decline thereafter.

Applications of iron to the soil, or in the irrigation water, have generally not been commercially satisfactory for treating iron deficiencies in lemon trees. Foliar sprays of available iron materials presently show the most promise. In one large-scale trial on mature lemons near Oxnard, yearly low-volume sprays of three iron compounds have shown increases in yield and fruit size. Leaf analysis for iron was found to be a poor indicator of response. A completely satisfactory method of correcting iron deficiency in lemons is still not available.