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In the imperial valley it has been a common practice for growers to apply high rates of nitrogen in the form of calcium nitrate, in an attempt to increase the growth rate of head lettuce during cold weather and to improve external head color.

Two previous articles in California Agriculture (November 1972 and April 1974) have repofled some climate effects on oranges and mandarins. This third and final report covers data obtained on Frost Marsh nucellar and Redblush nucellar grapefruit harvested over a period of five crop seasons beginning with 1967-68. Eureka and Lisbon lemons were harvested over four seasons beginning with 1968-69.

Principle control measures for BF include standardization of nursery stock for low BF potential in susceptible varieties like Nonpareil or selection of varieties with no BF potential. Avoidance of susceptible varieties in localities with prolonged high summer temperature may be required, as better information on relative susceptibility is obtained.

Non-infectious bud failure (bf) is a genetic disorder of almonds that is present in a number of commercial varieties grown in California. Nonpareil, the industry's most important variety, is widely affected in certain sections of the San Joaquin and Sacramento valleys.

The preceding article documents yield reductions in Nonpareil almond due to bud failure (BF). Since the yield data indicate crop reductions could potentially result in economic losses to almond growers, this study was developed to assist orchard managers in deciding what action to take when faced with BF. Three courses of action were evaluated: to maintain the BF trees, to graft, or to replant. Other alternatives, such as interplanting, are available in special cases but were not included in the study. The authors assume that normal non-BF trees will be obtained by grafting or replanting, and that a pathogen is not involved. The probability of meeting these assumptions is outlined in the previous articles.