California Agriculture, September 1973
Volume 27, Number 9
Shake-harvested grapefruit … type of removal … fruit injury … pruning
by C. D. McCarty, S. B. Boswell, P. F. Burkner, J. H. Chesson
Abstract Not Available – First paragraph follows: Coachella valley grapefruit have been successfully shake harvested with a removal rate of 90 to 98%. The inertia limb shaker developed by USDA personnel will remove the most fruit with the least damage when operated in short bursts of five to eight strokes at 325 to 350 cycles per minute, with a 3%-inch stroke at the shaker clamp. Injury can occur to the fruit as it swings against twigs and branches before detachment and as it strikes limbs and twigs during its fall through the tree to the catching frame.
Carnation fusarium wilt control with soil fumigation and fungicides
by S. T. Besemer, A. H. McCain
The best treatment of ground beds to control fusarium wilt in these tests was fumigation with methyl bromide. Bromide residues remaining in the soil after fumigation should be removed by leaching with water prior to planting. Where fusarium wilt is severe, as in the test area, annual fumigation is necessary. When large areas are fumigated, there should be less reinvasion from untreated areas.
Lettuce mosaic virus: … causes internal rib necrosis, … stimulates rusty brown discoloration … in cultivar climax
by Stella M. Coakley, R. N. Campbell, K. A. Kimble, Stella M. Coakley, R. N. Campbell, K. A. Kimble, H. Johnson, K. Mayberry, T. W. Whitaker
Lettuce has been the most important winter vegetable crop in the Imperial Valley for the past four years, averaging about 42,000 acres grown, and an average gross value of about $35 million. Lettuce grown for harvest in midwinter (December 15 to March 15) is planted from about September 10 to November 5. Plantings during October are largely of the cultivar Climax. During the winter harvest season of 1968–69, a disorder, later known an internal rib necrosis (IRN), occurred throughout the Imperial Valley in epidemic proportions just prior to harvest and caused serious losses in the field and in transit. Persons associated with the lettuce industry recalled the disease from past years but it had never been ranked as a major disease until 1969. No valid estimate was made of the losses from internal rib necrosis during the 1968–69 season but it was common for growers to abandon entire fields. Since then IRN has appeared sporadically in lettuce planted for midwinter harvest but not in epidemic proportions. In addition, a postharvest disorder (then called rusty rib) now called rusty brown discoloration (RBD), occurred on lettuce during storage and transit at 35°F. In February 1969, 90% of the lettuce shipments arriving in New York had RBD. The cause (or causes) of IRN and RBD has not been identified but environmental conditions (freezing temperature and rainfall), aqua ammonia damage and a synergistic reaction between beet western yellows virus and lettuce mosaic virus have been speculated as causes. Two papers presented here report the results of cooperative research by personnel of the California Agricultural Experiment Station, the California Agricultural Extension Service, and the US Department of Agricultural to determine the causes of IRN and RBD.
New strawberry irrigation systems
by Victor Voth, R. S. Bringhurst, Howard J. Bowen, Tom Mock
Water placement is very important to strawberry production. Under the conditions of this experiment, plants on a conventional 40-inch bed with standard furrow irrigation required the greatest amount of water and yielded the least fruit, whether figured on a per-plant or per-acre basis. In contrast, the experimental 60-inch midbed furrow-irrigated plants yielded significantly more fruit on a per-plant or per-acre basis, even though there was a 35% increase in plant population. Apparently surface application, with the water constantly moving downward, improves plant performance. Of the new application systems investigated here, only the use of porous pipe placed under the soil surface was of questionable value from the point of view of plant performance.
Jojoba … a brief survey of the agronomic potential
by D. M. Yermanos
Information available now suggests that jojoba can become a viable crop for semiarid lands. This potential, however, may be jeopardized if the implementation of a master plan for jojoba production is excessively delayed.
Eucalyptus fuel dynamics, and fire hazard in the Oakland hills
by J. K. Agee, R. H. Wakimoto, E. F. Darley, H. H. Biswell
This study reports the results of two years of fuel studies in blue gum eucalyptus stands. Fuel weights are related to stand densities, and the dynamics of fuel accumulation are investigated. Techniques for managing fuel loads in eucalyptus stands are discussed. Results of this study indicate that fuel buildup occurs very rapidly in unmanaged eucalyptus stands, and that to maintain low fuel levels, a fuel reduction program is essential. If prescribed fire is used, burning techniques that minimize air pollution must be used.
editorial, news, letters & science briefs
The (other) energy crisis
by J.B. Kendrick