Secondarily treated wastewater is used extensively in the southwestern United States for turfgrass irrigation, but deterioration in soil quality can occur from sodium (Na) delivered by this water. Application of gypsum (CaSO₄2H₂O) at 2 240 kg ha⁻¹ yr⁻¹ is often recommended to control the Na. Research to determine if this rate is effective on effluent -irrigated turfgrass sites is lacking. A 2-yr study was carried out on a golf course fairway (typic tomf7uvent soil) with a 10 yr history of effluent irrigation and elevated Na levels (800 mg kg⁻¹). Four rates of gypsum (0, 2 240, 4 480, and 8 960 kg ha⁻¹) were surface applied in November 1986 and 1987. Soil samples were collected every 3 months after treatment (MAT) and analyzed for Ca (total and water - soluble (WSCa)), Mg, K, Na, SO₄⁻²-S (S), pH, and electrical conductivity (EC). Results showed elevated WSCa and S levels 3 and 6 MAT in both years. The two highest rates resulted in elevated S levels 12 MAT. During both years, gypsum at the two higher rates decreased Na levels within 3 MAT. The lowest application rate did not reduce Na levels until 12 MAT in 1987 and its effects were not as great. Following the second annual application, the 2 240 kg ha⁻¹ rate was as effective as the higher rates in reducing Na levels 6 and 12 MAT. Total Ca levels were not affected by gypsum but Mg and K levels did decrease. In both years, a temporary increase in EC and decrease in pH occurred after gypsum treatment. It appears that gypsum at 2 240 kg ha⁻¹yr⁻¹ can be as effective as higher application rates in reducing Na in effluent-irrigated turf soil but only after two applications.

Repeat sequential applications (1 - 4) of imazaquin herbicide were applied to 100% pure stands of purple nutsedge during the summer of 198& Treatments were applied every two weeks. Maximum suppression for plots receiving only one application was reached 1 month after application (25% control). Two 14-day sequential applications achieved 60% control 2 weeks after the second treatment. Both 3 and 4 sequential applications resulted in 88% and 92% control after 2 and 4 weeks from the third and fourth applications, respectively. Resprouting eventually reoccurred on all plots. This data shows the enhanced effect of repeat applications of imazaquin for purple nutsedge suppression.

A field test was implemented at Paradise Valley Country Club to investigate the effect of two rates of imazaquin (Image) herbicide (0.38 and 0.50 lbs ai /a) in both the granular (G) and emulsifiable concentrate formulation on purple nutsedge and common bermudagrass in a mixed stand (85 ± 20% nutsedge).

An experiment was devised to evaluate application technique, and elucidate the plant response (herbicidal activity) of imazaquin herbicide on single plants of purple nutsedge. Herbicide treated plants showed increased filleting and stunting 31 days after treatment. Soil treatments tended to increase herbicidal response. Imazaquin activity was minimized when the herbicide was not irrigated into the soil. Soil applied-imazaquin postponed the emergence of shoots from viable nutlets, but did not prevent emergence altogether.

A one-time application of MON1S1S1 or 0.5 lb. ai /a on September 1, 1988, was evaluated for potential overseeding effects. Treated plots, which were overseeded with perennial ryegrass at 10, 20, or 30 lbs. per thousand square feet, were not significantly different compared to untreated plots for percent ryegrass stand and verdure. Only seed rate effects increased percent ryegrass and verdure weights slightly. These data show no detrimental effects of using MON15151 ("Dimension" trade name) six weeks before overseeding.

Tall fescue is a very heat and drought tolerant, cool season turf, which can remain green throughout the year in the arid Southwest. Data are lacking on the performance of tall fescue varieties in this location. Sixty-five tall fescue entries were established in November 1987 and their performance as a home-lawn turf rated for quality, color, density, percent ground cover, pest incidence and water use. All varieties performed very well during the first seven months of 1989, but a decline in August quality was observed during summer monsoons mainly due to the incidence of large brown patch (Rhizoctonia solani L.) and record-setting high temperatures. Turf still showed signs of stress by mid-September. Turfgrass irrigation water use from 1 January to 23 September totalled 43.3 inches (1100.5 mm) and averaged 63 % of predicted evapotranspiration.

This field experiment evaluated the use of secondary municipal sewage effluent for irrigation of two turfgrass species. In April 1987 common bermudagrass (Cynodon dactylon L. Pers.) was seeded to a gravelly sandy loans soil and maintained under fairway conditions. Perennial ryegrass (Loliman perenne L.) was overseeded in the fall to maintain an actively growing turf. Plots were irrigated identically with either effluent or potable water. Soil and irrigation water samples were collected periodically and analyzed for pH, electrical conductivity (EC), sodium (Na), calcium + magnesium (Ca +Mg), bicarbonates (HCO₃), nitrogen (N), phosphorus (P) and potassium (K). Effluent water was found to contain a higher sodium absorption ratio (SAR), EC and greater concentrations of all the above elements with the exception of pH. Effluent irrigation lead to significantly lower seed germination and resulted in higher EC, Na, nitrate- nitrogen (NO₃-N), P and K concentrations in soils. Turf quality was assessed by visual evaluation under four N fertilization rates in each irrigation regime. Established effluent irrigated turf did not show signs of osmotic stress with a 15-20% leaching fraction and responded to the nutrient content of this water during periods of higher irrigation rates. However, no single fertilization rate or irrigation regime consistently produced a superior turf quality. Secondary municipal sewage effluent was used successfully for turf irrigation but the greater EC, Na and nutrient content of the water need to be considered by the turf professional making management decisions.

Termites continue to be Arizona’s number one urban pest. Factors that influence the persistence of termiticides are constantly under investigation. High pH has been identified as a potential concern for persistence in termiticides. I studied the influence of pH 11 water on five termiticides applied to commercial ABC fill 10 months post-treatment. In general, the addition of pH 11 water had little influence on termiticide persistence under Arizona conditions. Initially plots treated with Ph 11 water had higher residues than those that did not receive the treated water; over time these differences diminished.

Termiticide applications are the standard practice in the pest control industry to protect structures from the invasion of termites. However, information related to termiticide persistence is lacking. In 2 field trials, soil residues analysis were carried out to determine degradation among existing and candidate termiticides in 3 different chemical classes. Plots were established to simulate industry standards for the application of termiticides. Study 1 termiticides tested were Dragnet FT (permethrin, 0.5% and 0.25%;), Prevail FT (cypermethrin, 0.25%;), Biflex FT (bifenthrin, 0.06%;), Fury TC (zeta-cypermethrin, 0.125%;) Premise 75 (imidacloprid, 0.05%,), Dursban TC (chlorpyrifos, 1% and 0.75%) and the untreated check. In Study 2 termiticides tested were DeltaGard SC (deltamethrin 0.075%, 0.125% and 0.25%); Dragnet FT (permethrin 0.5%;)and the untreated checks. In study 1, in general, all termiticides showed more degradation in the exposed plots than those covered by the concrete slab. In the exposed plots, specifically in the 4th year, four of the eight treatments had no residues In comparison, the covered plots had only 1 treatment, with no residues. In general the pyrethroids of permethrin at 0.25% and 0.5% along with bifenthrin at 0.06% held up longer than the organophosphate chlorpyrifos or imidacloprid the chloronicotinyl compound. Study 2, after one year, the exposed plots showed a slightly greater degradation than the covered plots. However, due to plot-to-plot variation no conclusions can be drawn from the data, other than the permethrin plots showed less than 40% remaining in any plot.

Cordia boissieri and Cordia parvifolia are plants commonly used in landscapes in the Southwest. Although they are available in the nursery trade, Cordia species are recalcitrant to germinate from seeds. The objective of the study was to determine a reliable propagation protocol for each species. Germination percentages for Cordia boissieri of 70 to 100% were obtained when seeds were stratified under warm conditions before germination. However, with prolonged storage seeds lose viability and age of the seed and seed storage conditions need further investigation. Seeds of Cordia parvifolia collected from local sources had low viability and did not germinate in response to several different seed treatments.