Calag Archive

Not available – first paragraph follows: At least 20 and possibly as many as 40 species of birds damage ripening grapes in California, but the economic importance of individual species has not been clearly defined. Several studies in California vineyards have documented the various types of birds that damage grapes or have estimated the overall damage due to all species. However, estimates of the damage potential of each species should not be based strictly on its relative abundance in vineyards: the different body sizes, feeding habits, and social behaviors of the various species also influence the amount of grapes they damage. A better knowledge of the actual damage capability of individual bird species could help grape growers predict potential damage severity from observed bird numbers, thereby allowing more species-specific and cost-effective bird damage control programs to be implemented.

Not available – first paragraph follows: The black vine weevil is widespread throughout the continental United States but, until recently, has been a sporadic and minor pest of numerous container-grown ornamental plants and several field-grown berry crops. This insect has been a more serious pest in the Pacific Northwest, however, and has been increasing in pest status in other areas, such as Ohio, New York, and Michigan. The black vine weevil is also a problem for nursery growers in Australia, the Netherlands, Germany, Norway, and England.

Not available – first paragraph follows: Fresh fruit tissues turn brown when bruised, cut, or otherwise damaged during harvesting and postharvest handling. This browning detracts from the appearance of fruits marketed fresh or used for processing. The extent of the discoloration depends not only on the severity of bruising, but also on the inherent browning potential of the fruits. Browning potential depends upon the total amount of phenolic compounds and level of activity of the poly-phenol oxidase (PPO) enzyme, which catalyzes enzymic browning in fresh fruits. Normally, phenolic compounds are separated from PPO enzyme in the intact tissue. Once the fruit tissue is damaged, PPO gets access to the phenolic compounds, and reactions leading to browning occur. These reactions involve the oxidation of phenolic compounds to form quinones, which are tightly unstable and polymerize quickly to form brown-colored products.

Not available – first paragraph follows: California pistachio production is a fast-developing industry: over 40,000 acres of trees have been planted in the past 12 years. Although a number of disease and insect problems are known to affect pistachios in California, “epicarp” lesion is considered one of the most serious problems, causing losses of 30 percent or more. Although it is termed “epicarp” (skin) lesion, it also affects the mesocarp (flesh), and the endocarp (shell) of the fruit.

Not available – first paragraph follows: In cooperation with local landowners in Napa County, we undertook a bio-mass project in 1977 to evaluate the potential of several tree species as energy crops on small acreages. This article updates tree growth information from two study areas near Calistoga, California, at the north end of the Napa Valley after two additional years of study (see California Agriculture, May-June 1982).

Not available – first paragraph follows: Most deciduous fruit and nut trees require a period of cold temperature below 45°F during the winter to induce dormancy and promote satisfactory fruit and shoot development in the spring. The length of cold period required, or chill requirement, has been established for most commercial fruit and nut varieties; values vary considerably among species. For example, most apple varieties require more than 1,000 chill hours; almonds generally need only 200 to 500.

Not available – first paragraph follows: During urban grid surveys in September 1982, San Diego County biologists discovered a new invading whitefly on avocado. Ray Gill, insect taxonomist for the California Department of Food and Agriculture (CDFA), identified the new invader as Tetraleurodes sp. Steve Na-kahara of the United States National Museum then confirmed both the identification and the fact that the whitefly was new to California. Gill and Naka-hara agree that this whitefly is the same undescribed species known from the Caribbean, Central America, Florida, and Mexico.

Not available – first paragraph follows: Most of California's sweet potato production acreage is in the central San Joaquin Valley. The crop is grown primarily on sandy soils, in which root-knot nematodes (Meloidogyne spp.) are commonly distributed and where they are most likely to cause loss of yield.

Not available – first paragraph follows: Larvae of the naval orangeworm infest almonds during and after hullsplit, rendering the nut meats unmarketable. The insect also damages other nut, fruit, and legume crops by invading dried or decayed fruit and occasionally by entering undamaged fruit.