Calag Archive

The lettuce root aphid, Pemphigus bursarius L., can cause considerable damage to crops of summer head lettuce. Its primary host is the Lombardy poplar, Populus italica var. nigra. The aphids, or “stem mothers,” which hatch in the spring from eggs that have overwintered on the poplar, cause hollow, flask-shaped galls to develop on the leaf petioles (fig. 1). The stem mother becomes enclosed within the gall, where it matures and gives rise to between 100 and 250 young.

To make the most efficient use of limited water supplies in the production of field crops, a sequence of key decisions must be made before planting. These decisions are particularly important in a drought year such as 1977 in California.

Nematicides dramatically increased yields but not enough to justify costs at current sugar prices.

A new phenomenon in California home ownership has led to an emerging problem of pestiferous insects: City dwellers moving into new housing developments built around man-made recreational lakes have been met with swarms of chironomid midges.

Commercially grown Acala cottons (Gossypium hirsutum L.), like most other species of the genus Gossypium, have evolved an effective chemical resistance that deters most plant-feeding animals. The biologically toxic component is a group of related, secondary plant metabolites known as terpenoids. Gossypol, the best known of these terpenoids, is a polyphenolic yellow pigment closely associated with the epidermal glands present on all aerial plant parts as well as in the cottonseed. Most commercial cottonseed contains about 1 percent gossypol, depending on variety and environmental conditions. Expensive chemical and physical procedures are used to remove gossypol from cottonseed products destined for use as food for non-ruminant animals.

Canned, unpeeled apricot halves are subject to softening disorders, which destroy the integrity of the fruit flesh. When the cans are opened, one, a few, or all of the halves may be completely macerated, or they may appear normal but disintegrate upon handling. The inability to detect the problem before the can is opened results in a significant number of dissatisfied customers, even if the fraction of affected cans is small.

Peach harvest begins about April 25 and continues for two weeks in the Coachella Valley. This district produces the first peach fruit of the season from California, but it is closely followed by other districts. Because the first shipments reaching market receive favorable prices, it is important to Coachella Valley growers that their peaches reach optimum market quality, particularly acceptable fruit size, as early as possible.

Whenever grain and hay prices are high, there is renewed interest in feeding cereal straws to growing cattle as a possible method of cutting costs. Feeding trials were conducted using cereal straws in rations formulated by a computer least-cost ration program. The growing phase compared barley straw with wheat straw with a further comparison of cottonseed meal (CSM) and urea as the nitrogen source. A standard ration was fed during the fattening phase.

Trees in most mature peach, nectarine, and plum orchards in the southern San Joaquin Valley cease growth by early to mid-October. Because the foliage often persists on the trees for another three to five weeks and interferes with the pruner's vision, it is impractical to start annual pruning immediately. Thus, any means of stimulating defoliation in mid-October that would allow an earlier start on pruning could become an important factor for progressive farm labor managers. Under normal conditions, many farm laborers are idle from mid-October through mid-November, because harvest of most other crops is nearly completed. The availability of defoliated trees by mid-October would provide work when the unemployment rate is high and would extend the period over which dormant pruning could be accomplished.