Three 12-year-old Prosopis chilensis were successfully layered in spring and late summer. The best rooting occurred with 1 cm stems treated with either 5,000 or 15,000 ppm IBA. Air-layers treated with IBA had a higher rooting rate and better root quality than untreated air-layers.

Flower bud abortion, or "blasting" was shown to be at least partially caused by treating plants with ethephon, a chemical that releases ethylene. In floricultural greenhouses, ethylene could accumulate to levels that could induce commercially significant levels of flower bud injury. Silver thiosulfate (STS) was shown to be a potent inhibitor of ethephon injury. STS at (1 to 2 mM) could be applied as early as the visible bud stage (approximately 5 to 6 weeks before flowering) without phytotoxic effects. Using current silver prices, the material cost for our treatment is less than 0.4 cents per plant. Based on these results, a preventative STS application could potentially reduce much of the flower bud abortion seen in commercial greenhouses.

Scarification and stratification requirements of Mexican redbud and evergreen sumac seeds and the effects of temperature on Mexican redbud evergreen sumac, and mealy sage seed germination were investigated. The maximum predicted germination from a quadratic response surface was 94.9% after 62 minutes scarification and 35 days stratification for Mexican redbud and 59.3% after 52 minutes scarification and 73 days stratification for evergreen sumac. Mexican redbud seeds germinated from 23.8 to 30.5 C, evergreen sumac from 20.8 to 30.6 C, and mealy sage from 20.6 to 34.2 C. Maxium predicted final percent germination and the temperature at which it occurred for Mexican redbud, mealy sage, and evergreen sumac was 104.2 at 27.5 C, 89.8 at 29.2 C, and 42.4 at 22.1 C, respectively

Desert willow and yellow bells had a higher capacity to avoid drought than fruitless mulberry under moist conditions, but the reverse was true under dry conditions. Desert willow and yellow bells had a higher tolerance to dehydration than fruitless mulberry, resulting in a higher relative resistance to drought under either moist or dry conditions. Detached leaves from desert willow and yellow bells plants grown under stress restricted water loss better than those grown under no stress. Fruitless mulberry leaves lost water at essentially the same rate regardless of irrigation.

In 1987, 191 golf facilities in Arizona were surveyed to determine the employment, income, revenues, and expenditures generated by the state's golf course industry. The direct plus indirect employment and income benefits are estimated to be 12,400 jobs and $155 million in wages, respectively.

Overseeding trials were conducted to evaluate the turf-type fitness of cool season grasses for use in the desert when bermudagrass is dormant. Perennial ryegrass, fine fescues, rough stalk bluegrasses and creeping bentgrasses were tested for turfgrass quality, color, percent ground cover and uniformity under a close mowing (3/8 inch) regime. Entries varied significantly from each other once seasonal hard frosts did not recur after January. Certain entries had better turf performance under hot (late spring) conditions. Both commercially available and experimental germplasm were evaluated.

Curly mesquitegrass, Hilaria belangeri, is being evaluated for utilization as a desert turf. Experiments were conducted on plant material collected throughout Arizona to: (a) quantify the natural variation in turfgrass qualities in this species; (b) evaluate the field performance of selected plant material to fertilizing and mowing practices; and (c) assess the effects of planting date and seeding rate on seedling establishment. Thirty-four percent of the rated plant material displayed low growing height while 26.9 % of the plant material had short leaf length. Thirty-five and 23.5 % of the rated plant material had acceptable or better than acceptable color ratings and fine leaf width, respectively. In another experiment, nitrogen had no significant effect on plant color, however, increasing nitrogen increased percent ground cover. Percent ground cover also increased as the height of cut increased. Substantial variation was observed in the number of stolons per plant, and high stolon numbers were not associated with high nitrogen levels. Planting time had a significant influence on seedling establishment. Seeding rates also differed significantly in the number of seedlings established per m².

Mechanical scarification greatly improved the germination of Lehmann Lovegrass seed. Depending on the type and duration of scarification, seed gemzination can be improved from 10 %-12% germination (untreated seed) to over 90% (60-second scarification in a commercial seed scarifier). Black grama is sensitive to both dehulling and dehulling followed by scarification. Unhulled black grama seed should be used for field plantings.

A Florida strain of sweet potato whitefly, Bemisia tabaci (Gennadius), was found to have an expanded range which includes several new food crops. To determine why, we examined how it processes plant nutrients. The amino acid and carbohydrate content of phloem sap of poinsettia and pumpkin and of honeydew produced by the Florida strain and a strain from Arizona feeding on both plants were analyzed. Poinsettia phloem sap contained 15 amino acids; 14 of these were in pumpkin phloem sap. Almost all the same amino acids were in the honeydews produced by the two strains on the two hosts. Approximately half of the amino acids found in the honeydew were at concentrations which were significantly lower than concentrations in the phloem sap. Honeydew from both hosts contain six additional amino acids. The major one was glutamine which may be used to expel nitrogen. Carbohydrates in phloem sap and honeydew were common transport sugars, like sucrose. Both honeydews contained trehalulose, a disaccharide not previously associated with insects. Both strains processed phloem sap and honeydew from both plants in the same manner, but the Florida strain produced significantly larger quantities of honeydew; it is therefore assumed to process more phloem sap. Since this strain has access to more phloem sap it also has access to more of the amino acids which are in short supply in the phloem sap of some plants allowing it to broaden its range.

Effect of cutting age (weeks after budbreak) and IBA concentration on percent rooting of Mexican redbud, larchleaf goldenweed, littleleaf ash, and evergreen sumac were investigated. Maximum predicted percent rooting was 88% for cuttings of Mexican redbud taken 4 weeks after budbreak and treated with 21 gliter⁻¹ IBA, 99% for cuttings of larchleaf goldenweed taken 6 weeks after budbreak and treated with 16 gliter⁻¹ IBA, 86% for cuttings of littleleaf ash taken 16 weeks after budbreak and treated with 17 gliter⁻¹ IBA, and 24% for cuttings of evergreen sumac taken 16 weeks after budbreak and treated with 5 gliter⁻¹ IBA.