Calag Archive

BARLEY YELLOW DWARF, an apid-transmitted virus disease of small grains, has caused serious losses in barley, wheat, and oats in California since its sudden widespread outbreak in 1952. Although it had not been recognized prior to that time, yellow dwarf is now known to be a major disease in most of the small-grain-producing areas of the world.

MUCH OF OUR PRESENT RESEARCH effort is directed towards mechanizing the harvesting of our California vegetable crops. This is as true for cantaloupes as it is for asparagus, lettuce, and fresh market tomatoes. Agricultural engineers and plant scientists generally agree that mechanical harvesting of cantaloupes on a commercial scale is still several years in the future. The principal obstacle to machine harvesting of cantaloupes has been the absence of a variety which will mature fruit of acceptable quality in a determinate manner so that the crop can be harvested in a single once-over operation much the way canning tomatoes are harvested.

THE LENGTH OF HARVEST SEASON for asparagus is frequently determined by economic factors or by factors other than a consideration of how the length will affect the plants and future performance. One of the most widely used practices is to terminate the harvest when the plants show a decrease in spear size. This termination is usually done arbitrarily and may occur after permanent damage to the field has taken place.

RECENT EXPERIMENTS have shed new light on two age-old and seemingly unrelated questions: why potassium is essential for plant growth; and how the stomata on leaves open and close.

IT IS OFTEN DESIRABLE to prevent fruit formation on many ornamental plants to eliminate a hazard or a nuisance created by the ripe fruit. The fruits of olive (Olea europaea L.) and Victorian box (Pittosporum undulatum Vent.) are messy and unsightly, they stain concrete and other surfaces, and can cause people to slip. The long-term solution has been to introduce and use fruitless cultivars or male plants. This, however, does not eliminate the need for other control methods because many cultivars which set fruit can usually be found in the neighborhood.

THE RAGWORT FLEA BEETLE, an insect from Europe that attacks the root crowns of tansy ragwort, Senecio jacobaea L., has been released near Fort Bragg and at Smith River, California. This insect, Longitarsus jacobaeae (Waterhouse), will supplement the earlier liberations by the Biological Control of weeds Investigations Laboratory, ARS, USDA, Albany of two other insects: the cinnabar moth, Tyria jacobaeae (L.), which feeds on the foliage, and the seed head fly, Hylemya seneciella (Meade), which attacks the seed in the flower heads (california agriculture, December 1969).

Advertising has encouraged the consumer to buy elongated apples, although the shape of the apple has no bearing on its ultimate quality. The effectiveness of the advertising campaign has resulted in a premium price for elongated fruit. Several investigators in the past 50 years have attempted to explain why apples from some areas are more elongated than apples from other areas. Most investigators now believe that elongated fruit are produced in areas where temperatures are cool for about

IN MID JULY, a heavily bearing six-year-old Bartlett pear orchard infested with two-spotted mites was offered to the Extension Service for the remainder of the season for the purpose of testing acaricides. Since the fruit from this orchard was not to enter commercial channels, it afforded an opportunity to test unregistered acaricides.