Twenty-one clonal selections of saltgrass (Distichlis) were evaluated in March and May for initial green-up, plot growth, unmowed canopy height, number of satellite plants emerging from rhizomes and floral expression. Accessions were statistically different for all variables measured. Colorado’s accessions (5 of 7) were upright in growth habit and had the greatest number of satellite plants at the surface in March. These plants also had the greatest percent plot coverage. Arizona’s accessions had lower growth in height, were more compact in growth and were less sprawling. However, their plot coverage (grow-in) was not as great as the upright, rapid growing Colorado accessions. Of the twenty-one clones included, thirteen are males and eight are females, with expression ranging from 1 to more than 200 flowering culms per plot.

Twenty-one clonal selections of saltgrass (Distichlis spp.) were evaluated during the first full summer growing season (May - October 1999) for turf characteristics and general adaptation. Initial percent plot cover in May ranged from 8% to 42% among clonal accessions. Accessions which produced the highest unmowed canopy heights had the greatest initial cover in May. This trend reversed itself by August and September whereby entries which exhibited less elevated foliage tended to produce turfs which had higher shoot densities, greater percent plot cover, visual estimates of density and more acceptable overall turfgrass quality under accumulated mowing pressure. The "treatment" (clonal accession) affect was significant on all dates for all field variables demonstrating clearly that differences exist for growth parameters of Distichlis screened under mowing stress.

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Two species of entomopathogenic nematode were studied in terms of their survivability, detectability by the subterranean termite Heterotermes aureus, and their ability to induce mortality in H. aureus. Heterorhabdidtis bacteriophora (Poinar) and Steinernema carpocapsae (Weiser) are nematodes sold commercially as a means of biological control for termites. We used a laboratory method to determine how effective these nematode species might be under field conditions. Tests showed a difference in the survivability between nematode species and also ability to kill termites. It was also shown that H. aureus had no ability to detect either nematode species when given a choice between arenas infested with nematodes and not. Though nematodes might have some limited capacity for termite control, those considering using nematodes to control Heterotermes aureus may want to consider the species of nematode before making a purchase.

Staking is a common practice following planting of most trees in the landscape. The objectives of this project were to demonstrate four methods of staking trees and the effect on subsequent caliper growth and taper development. Master gardener volunteers were involved in this project. Four methods of staking were used on two different tree species. Acacia stenophylla were 3.1 m tall at planting and were difficult to keep upright with one or two tall stakes. All acacias staked with root stakes or short stakes required corrective pruning to establish a new leader. Prosopis velutina staked with root stakes or short stakes developed greatest taper within 6 months after transplanting. Root stakes will not require removal of staking materials.

The objective of this study was to determine the optimum rate of N to maximize growth of Prosopis velutina seedlings and minimize N leaching when seedlings were grown in different substrates. Mesquite seedlings were grown in sand or soilless media and were fertigated with a solution of67 % NH₄⁺: 33 % NO₃⁻ at a rate of 25, 50, 100, or 200 mg N/L. After 60 days, plants in media produced 41 % more leaves and total biomass compared to those in sand. Leaf number was greatest for plants grown at 200 mg N/L in both substrates. Root biomass of plants in media showed no response to increasing N concentrations while root biomass of seedlings in sand were similar for the three lower N concentrations and nearly doubled for the highest one. Shoot biomass of seedlings receiving 25, 50, or 100 mg N/L was similar, but more than doubled for plants fertigated with 200 mg N/L. N leachate losses were highest from seedlings growing in sand and receiving the two higher N fertigations, those in media had greatest N leachate loss when fertigated at 200 mg N/L.

The combination of Spotlight* at 1.0 pt/A plus Speedzone* at 4.0 pt/A gave 90% control of khakiweed at 14 days after treatment (DAT) and continued to offer acceptable control of 85% at 49 DAT. Acceptable control of 87 and 90% control was also observed at 14 DAT when Spotlight* was combined with Powerzone* or Speedzone*, respectively. The combinations of Spotlight* with Powerzone* or Trimec* were similar by marginally controlling khakiweed up to 21 DAT. Spotlight when combined with Turflon Ester* or Speedzone Southern* performed very similarly at all rating dates and did not offer acceptable khakiweed control.

Two or three applications of Velocity at 30 g ai/A controlled P. annua 63 to 82% in two field experiments. Multiple applications of Velocity at 17 day intervals provided a higher degree of P. annua control compared to applications made at 28 day intervals. At approximately one month after initial applications, Velocity treatments, single or sequential, demonstrated 50 to 77% control of P. annua. The activity on P. annua was minimal at two weeks after initial applications of 30 to 60 g ai/A and slight chlorosis was evident. Perennial ryegrass exhibited chlorosis at two weeks after applications and appeared to recover at one month.

Seed head production from Poa annua is problematic on winter turfs, whether they are overseeded or not. Flowering culms are unsightly, prevent a uniform surface, and insure a continuous crop of seeds for the future. A field test was conducted to evaluate the effects of PROXY and a PROXY/PRIMO PGR tank mix for seed head control. Treatments were applied on three different dates in order to evaluate the degree of response of treatments and help define treatment window applications for future programs. PROXY when applied alone at 5 ounces/product/M produced a maximum of 60% seed head control at 26 days after a single application on February 15, and 83% seed head control at 27 days after a single application on March 1. A tank mix of PROXY/PRIMO (5.0/0.25 ounces/product/M) generally produced greater seed head control than PROXY alone. The tank mix produced seed head control effects quicker, greater, and longer than PROXY alone. Seed head suppression and percent seed head control was greatest when products were applied initially on either February 15 or March 1, 2001. PROXY/PRIMO produced the darkest color turf when applied on either February 15 or March 1. At least three tank mixes seem to be needed, applied monthly to suppress/control seed heads throughout the winter/spring season.

Post emergence applications of penoxsulam herbicide were generally ineffective in weed control of Khakiweed, (Alternanthera pungens). Moderate control was achieved by the high rate of granular Penoxsulam (0.052 G, 180-lbs. acre). This treatment had 28%, 34%, and 32% Khakiweed control on September 20, September 23 and September 29, respectively. Other rates resulted in minimal or negative control. The liquid SC formulation provided minimal control, at rates tested. Penoxsulam did discolor khakiweed, but did not cause enough injury to result in stand reduction. Further aspects for investigating Penoxsulam for control of this weed is presented.