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  • Author or Editor: Robert E. Call x
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The San Pedro River has been impacted by continued growth of Fort Huachuca Military Base. The San Pedro River, a riparian-migratory area, has had continuous water flow but now has intermittent water flow. The cause is cones of depression in the aquifer due to domestic well pumping. The aquifer is recharge with water from the river. Cooperative Extension has implemented Resource Conservation Audits for landowners in the lower San Pedro Valley. Also, outdoor classrooms are being constructed at three schools to educate children and community members. The goal of these programs is to educate landowners on water conservation through the use of native and adapted drought-tolerant plants, xeriscaping, irrigation efficiency, water harvesting, soil erosion, and composting. Site visits help landowners identify opportunities to reduce water use. Research-based informational brochures have been produced so landowners can plan and implement water-saving techniques on their properties. This program has been implemented using six members of the Border Volunteer Corp., part of Americorp program.

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Studies were established in 1992 and 1993 in a mature commercial pistachio orchard to determine the effectiveness of several fungicides for control of septoria leaf spot (Septoria pistaciurum). Fungicide treatments used in 1992 were Bravo 720F at 3.0 lbs./A (ai.) and 4.5 lbs./A a.i.; Kocide 101 50W at 8.0 lbs./A a.i. plus Benlate 50W at 1.0 lb./A a.i. Fungicide treatments in 1993 were Bravo 825 WDG at 3.0 and 4.5 lbs./A a.i. and Benlate 50W at 2.0 lbs./A a.i. Treatment replications consisted of two treated trees separated by nontreated trees within the row and nontreated tree rows dividing treated rows. At crop maturity, disease severity was determined by counting the number of leaf spots caused by septoria on ten leaves collected at random from each of the two trees of each replicated plot. All treatments significantly reduced disease severity compared to trees receiving no fungicide treatments. Experimental plots were too small to detect any apparent effect of fungicide treatments on yield. Leaves around nut clusters not receiving fungicide treatments were senescent at crop maturity, while leaves on treated trees showed no sign of senescence.

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Mating disruption of codling moth using codlemone pheromoneemitting twist-ties or cards has become a standard practice in many orchards. This study was initiated to determine the effectiveness of NoMate CM EC, a spray formulation of codlemone pheromone. Treatments were applied 20–21 Apr. 1995 to plots measuring 99 × 244 m of 15-year-old `Golden Delicious' apple trees on seedling rootstock. Trees were spaced 3.7 × 5.5 m and treatments were made in a randomized complete block design replicated three times. Whole trees were sprayed to run-off using a handgun. Treatments were 20.2 g a.i. NoMate CM EC/h and a watered sprayed control. Two pheromonebaited, sticky traps were placed in each replicate to monitor codling moth activity. Moth counts were made 3 days after treatment and continued twice weekly for 4 weeks. Results indicated very little moth activity for the first 14 days of the study in plots treated with NoMate CM EC when compared to the control. However, after the first two weeks differences between treatments were not significant.

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A thinning-timing study of apple, (Malus domestica Borkh. cv. `Royal Gala'), grown on M7a rootstock, was initiated during the Spring of 1992 to determine the optimum and last effective thinning date to affect `Royal Gala' apple size. Trees planted in 1987 in sandy-loam soil and trained on a three tier Ebro trellis system were used in this study. Thinning-timing treatments were begun at full bloom and continued weekly for four weeks making a total of five thinning dates and an non-thinned control. Each treatment's flowers and/or fruits were hand thinned to 15 - 20 centimeters between fruit on tree limbs. Measurements of the diameter of marked apples from each treatment were made weekly during the growing season to plot growth curves. Results show a significant difference of larger fruit size and weight of second and third thinning treatment dates as compared to the other treatment dates and the control.

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Abstract

Various coating treatments werre applied to ‘Johnson Elberta’ peach [Prunus persica (L.) Batsch.] trees before budbreak to delay bloom and slow deacclimation. Phenological development was monitored by comparisons with a bud stage chart and hardiness was tested using a programmable freezing chamber. Applications of dormant oil at 2%, 5%, 10%, or 20% were equally effective. In 1984 and 1985, bloom was delayed 2.0 and 1.3 bud stages (5 days) and flower bud hardiness was increased 4.2 and 1.6C, respectively, when compared to the control. Oils applied at 20% concentration were phytotoxic to flower buds. Adding daminozide to various oil treatments produced no additional effect. Chemical name used: succinic acid-2,2-dimethyIhydrazide (daminozide).

Open Access

Measurement of nutrients in leaf tissue is a practical method of monitoring the nutritional status of perennial crops such as pecan (Carya illinoinensis, Wang. C. Koch). Accurate interpretations require known standard concentrations for the crop and region. To determine standard concentrations for pecans, focusing on those grown in the desert southwest, we conducted a survey of 135 `Western Schley' pecan trees in Arizona for 2 years. Leaf nutrient concentrations and yield were collected for each tree. Leaf nutrient concentrations from the highest yielding trees (50th yield percentile) were used to calculate a mean and CV for each nutrient. Results were compared with data from New Mexico, Georgia, and Sonora, Mexico. Relatively large differences were noted in mean K, Ca, B, Cu, Fe, Mn, and Zn levels. Nutrient interpretation ranges were calculated based on Arizona population statistics using the balance index method.

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