Calag Archive

EYEWORM INFECTIONS are of economic importance in parts of Europe, Asia, and Africa, where about a dozen species of nematodes of the genus Thelazia inhabit and irritate the eyes of a variety of large mammals, including such domestic animals as cattle, horses, buffalo, camels, dogs, etc. The half-inch long worms live on the surfaces of the eye membranes, under the eyelids, or with some species, in the tear ducts or nasolachrymal canal. Ocular disturbances range from mild inflammation, commonly manifested by excessive tearing and photophobia, to occasional severe dysfunction, even blindness, of affected eyes.

Lint yields of Acala cotton varieties were increased an average of 10.9% by planting in narrow rows. Increases were even greater in a few genotypes better adapted to the higher plant populations provided by narrow rows. This research demonstrates the potential for higher yields, harvested once over, in 180 to 200 days from planting to harvest.

THE COMMERCIAL PISTACHIO nut tree (Pistacia vera L.), like all species of Pistacia, produces male and female flowers on separate trees. Male trees are strategically located among females in the orchard to provide pollen at the time the female flowers are receptive. Although the bloom period of the ‘Peters’ cultivar (male) generally overlaps that of ‘Kerman’ (currently the only female cultivar being planted commercially), in some years all the pollen is shed before the last of the ‘Kerman’ flowers is pollinated.

Young lightweight beef calves can be grazed on irrigated pasture with gains comparable—on a metabolic body size basis (wt 3/4)—with those for yearling cattle. When all or part of their diet was from irrigated pasture, more individual variation in average daily gain (ADG) occurred in calves as compared with yearling cattle. A high stocking rate can compensate for lower per head gain with calves. Steer calves gained approximately 10% more than heifer calves. Supplementation with rolled barley at 20% of expected dry matter intake did not improve gains but permitted a marked increase in stocking rate. Alfalfa cubes can be a successful supplement to calves on pasture when fed three times per week at a high stocking rate.

Sunflower varieties having plants with armored-layer seeds resulted in a high reduction of seed damage caused by larval feeding of the sunflower moth, Homoeosoma electel-lum (Hulst). Several sunflower lines were significantly more resistant to seed damage when the plants had armored-layer seeds than when the same lines had non-armored-layer seeds. The association of the armored layer with moth resistance was also shown by its significant reduction in the number of emerging adults. However, the same lines having plants with no armor still retained some resistance (compared with the check), which indicated that some chemical factors were also involved. Laboratory tests also indicated that the nature of resistance was partially chemical.

THE PEAR RUST MITE, Epitrimerus pyri Nalepa, has been a persistent but sporadic pest of pears in California. When present in the orchard, it is of major concern to growers because the russeting type of feeding damage can affect the market value of the fruit. Russeting can be caused by a relatively small number of mites beginning early in the season, while very high mite populations can cause defoliation. It is therefore sometimes necessary to use chemical controls against this mite, particularly when chemical controls for other pests destroy the mite's predators.