Calag Archive

Undesirable seediness in strawberry fruit of the Tufts variety has been observed under various growing conditions throughout the fruiting season. This periodic occurrence of seediness has limited the acceptance of this new variety. The seedy appearance was thought to be caused by adverse climatic conditions, heat, powdery mildew, growing methods, or chemical phytotoxicity.

In addition to monitoring and summarizing the use of pesticides and other restricted chemicals as required under the California Agricultural Code, the collection of Use Reports by the California Department of Agriculture has facilitated the establishment of a data bank. This data bank is the source of detailed information, hitherto not available, on when, where, and how the chemicals were applied throughout the state over an extended period of time (five years to date). It is now possible to prepare graphs showing trends and changes in pesticide use, and to estimate the pesticide load for simulation modelling of dissipation and decomposition of selected compounds. In conjunction with the mapping program, the information in the data bank has been used to graphically depict areas of heavy application. Therefore, suitable areas for field monitoring of pesticides can be selected for air and soil sampling studies. The data balnk has also been used as an information source by various state and federal agencies, including the State Department of Water Resources, Environmental Protection Agency, Monterey Basin Monitoring Project, and several departments of the university.

This trial shows that mycorrhizal fungi helps peach seedlings extract zinc from the soil. The fungi were equally or more effective in overcoming soil-fumigation nutrient-deficiency effects in peach nursery seedlings than the standard nursery practice of side-dressing phosphorus and zinc at planting time. Further studies are under way to determine application and placement methods which show the greatest inoculation efficiency in peach and other plant species.

Significant reductions of seven species of flies breeding in poultry manure were attained over a 20-month period through procedures that favored the natural increase of predatory and scavenger arthropods and by periodic inoculative releases of four parasitic Hymenoptera. Parasite releases during springtime had an apparently greater direct effect on fly reduction than did similar releases in the summer. Autumn releases were not evaluated. A minimum manure height of 8–12 inches (20–30 cm) was considered essential for minimum fly production. The importance of manure stability and importations of additional beneficial species are also discussed.

The dusky-veined walnut aphid, Panaphis juglandis (Goeze), appears in three distinct forms: alate viviparous parthenogenetic females, apterous oviparous females, and alate males. Commonly, only the alate viviparous parthenogenetic female form of this aphid can be found during the spring and summer months. The apterous oviparae and males appear during the fall. This suggests that temperature, day length, or host plant (English walnut) condition influences form.

Satisfactory reduction of sunflower head and seed damage by the sunflower moth, Homoeosoma electellum (Hulst), was afforded by carbofuran at both 1 and 2 Ib Al/acre, but seed weight per head was significantly increased only by the 2 Ib dosage. A misci-ble formulation of methyl parathion at 1 Ib Al/acre resulted in satisfactory reduction of seed damage and an increase in seed weight. An encapsulated formulation of this pesticide was not as satisfactory for control and did not significantly increase seed weight. Methomyl resulted in good reduction of damage, but did not significantly increase yields. Dipel (HD-1 strain of Bacillus thuringiensis Berliner var. kurstaki de Barjac and Lemille) was unsatisfactory for control. Methidathion at 1/2 Ib Al/acre and at two applications afforded very good sunflower moth control, reduction of seed damage, and significant increase in seed weight per head.

A year of immense grape production, record wine inventories, and slowing sales has focused intense interest on the California grape economy. As in the past, the wine supply situation is of particular concern. This report describes the emerging supply situation and investigates some of its implications.