Calag Archive

WITH MODERN RAPID MILKING techniques today's high producing dairy cows often are not in the milking barn long enough to consume sufficient concentrates to fulfill their energy requirements for high milk production. Elaborate concentrate feeding guides based on varying milk production levels are useless if the cow does not have time to consume her allotted amount. In many barns and parlors, the correct amount of feed is given to high producing cows but often some is left behind for the next cow. Some dairymen have attacked the problem by feeding a portion of the concentrates with roughage outside the milking parlor. A base amount of 5 to 10 lbs per cow is fed outside daily and the remainder is fed in the milking parlor.

PHYTOTOXIC RESPONSES of fruit trees to soil-persistent herbicides have been observed to vary considerably from orchard to orchard, and both sprinkler and flood irrigation have been associated with more injury in sandy soils than has furrow irrigation. The series of orchard irrigation-herbicide studies reported here were conducted from 1963 to 1968 to obtain further information on these problems. Five field experiments comparing furrow with flood irrigation and different levels of sprinkler irrigation were conducted at four different locations—three in Fresno County and one at Riverside. Trees ranged from one year to 20 years in age. All but two trials were conducted on first- or second-year peaches, plums, and almonds. The soils varied in content of organic matter from 0.6 to 2.1 per cent. The sand ranged from 40 to 67 per cent, silt from 24 to 39 per cent, and the clay from 9 to 20 per cent. The herbicides tested included simazine (Princep), diuron (Karmex), terbacil (Sinbar), dichlobenil (Casoron), and fluometuron (Cotoran).

CATTLEMEN HAVE OBSERVED that calves dropped early in the calving season arc heavier at weaning and more profitable than calves dropped late in the calving season. Animal scientists have pointed out that weaning weight is the result of age at weaning and average daily gain from birth to weaning. Actual differences under California annual range grazing conditions have not been reported in any detail.

I in the fall of 1967, the nematode Longidorus africanus Merny was found in soil around the roots of stunted lettuce seedlings in the Imperial Valley of southern California. The seedlings appeared wilted and chlorotic and the tips of the tap roots were swollen and sometimes necrotic. Greenhouse experiments proved L. africanus to be a pathogen of head lettuce, and field samplings during 1968 showed the nematode was widespread throughout the valley. Many crops such as cotton, sorghum, alfalfa and sugar beets are hosts of this nematode. Preplant soil fumigation with 1,3-dichloropropene hastened crop maturity and significantly reduced tap root damage. The reasons this pathogen was only recently discovered are believed to be primarily: (1) the previous absence of surveys for nematode pathogens of head lettuce; (2) shorter fallow period between lettuce and the previous crop; (3) recent precision planting of the lettuce.

THE VALUE OF A CORRECTLY TIMED supplementary feeding of honey bees with natural pollen, or with a combination of drivert sugar and natural pollen, has been demonstrated in Fresno County during four field-scale experiments. Each of these experiments included 60 bee colonies which were rented for crop pollination of almonds and alfalfa seed during 1968 and 1969. The provision of a pollen and sugar source two and a half to three weeks prior to the occurrence of the first natural bloom in the area caused a rapid increase in the queen bee's egg laying activity. A 2-lb feeding of drivert sugar and a 1 per cent pollen was adequate to maintain the rapidly growing colony population for the three weeks prior to natural bloom. The timing of the stimulant feeding is important, since it takes 21 days for a brood cycle of worker bees to mature.

THE YUMA SPIDER MITE, Eotetranychus yumensis (McGregor), was first observed near Yuma, Arizona, in about 1928 by J. L. E. Lauderdale, and was described in 1934 by E. A. McGregor from specimens collected on lemon foliage by R. S. Woglum and H. C. Lewis. This mite occasionally becomes a serious pest on citrus in certain desert regions of the southwestern United States, but little information has been published on its life history, distribution, host range, and the means of reducing injurious populations.

A more branched, fibrous root system is possible by chemically pinching the roots of young container-grown nursery plants. Copper naphthenate painted on the bottom of the seedbed was effective and easy to use. Treated seedlings formed more lateral roots than untreated plants. Root pruning to prevent roots from being kinked and twisted when transplanted was minimized. This technique should be particularly adapted to taprooted plants.

METHODS OF TRAPPING WINGED aphids in the field during studies of the incidence and spread of plant viruses have included sticky board traps, yellow painted open pans of water, and mechanical suction traps. Sticky board traps require the least attention, but collect fewer aphids than the other traps. The suction trap is the most efficient, but requires an electrical power source and is expensive. Although it collects more aphids of certain species which are attracted by yellow, the yellow pan trap has been favored by many researchers for the field survey of aphid vectors of plant viruses because of its overall efficiency in attracting known aphid vectors.