Drip irrigation of cotton in Maricopa County decreased from 13,335 acres in 1984 to approximately 600 acres in 1987 at five locations. The most common reason was that drip was not cost effective.

Cotton was grown using a computer model to schedule irrigation; yields of 2.5 bales per acre were produced. Even though some discrepancies were seen between calculated and measured soil moistures, the model was considered successful. No yield differences were seen between cotton grown with small, frequent irrigations and large, infrequent irrigations. The plant heights, however, were significantly altered.

Two planting dates, March 28, and April 28 were used to study the effect of soil temperature during planting on black root rot of cotton. Also, several cotton varieties were evaluated for response to the disease under varying soil temperatures and inoculum levels.

Eight short staple varieties were evaluated for severity of symptoms, percent of plants infected and yield while being grown in a Verticillium nursery on the Safford Agricultural Center. Delta Pine 90 showed the least severe symptoms, had the least number of infected plants and also yielded the highest. Another Delta Pine variety, DP 77, showed moderate symptoms and a 96% infection rate, but it still managed to come in third in yield, only 49 pounds per acre behind DP 90. Yield potential and varietal adaptability must be considered along with Verticillium wilt resistance in deciding what variety to plant, even in a field infested with Verticillium.

Residual effects from methyl bromide applied in 1986 showed increased yields in 1987. Increases from 115 to 281 pounds of lint per acre were observed, depending on the rate applied in 1986. This residual effect increases the possibility that this soil sterilant will be a useful tool to combat Texas root rot. Differences were also noted between 1986 and 1987 applications.

Methyl bromidelchloropicrin, a soil sterilant, was deep-injected into cotton beds ten days before planting. Within the kill areas of the Texas Root Rot, the soil sterilant had some significant effects on the mortality and yield of the cotton.

Weather conditions leading to the development of southwestern rust on cotton were evaluated at 3 locations in southeastern Arizona. Rust appeared following an extended period of wet, humid weather. In excess of 16 hours of wet canopy/high humidity conditions were observed on two consecutive days between 5 and 7 days prior to the appearance of rust. Temperatures during the wet canopy/high humidity periods were moderate, ranging from 65 F to 76 F. Afternoon rain showers initiated these extended periods of wet canopy /high humidity conditions.

Cultivars and germplasm lines of cotton, Gossvpium hirsutum L., differed in response to infection by the cotton leaf crumple virus (CLCV). The most widely grown cultivars in Arizona and southern California, 'Deltapine 90' and 'Deltapine 61', are susceptible, while ' Cedix', developed in El Salvador, and 'Coral', developed in Nicaragua, are highly resistant or immune. Nineteen other lines from a resistance breeding project in Nicaragua showed highly variable responses.

No description available.

Research on futures price behavior indicates that farmers may find it feasible to use selective hedging or forward contracting to increase gross receipts from the sale of their commodities. University economists have been telling farmers for many years that selective hedging-hedging only in some years rather than all years or no years -- should not be considered as an alternative to hedging every year or never hedging. If selective hedging is to be a feasible strategy for farmers, they must have some system for correctly predicting the direction of futures price changes during the production period in most years.