Rove beetles (Osorius planifrons) can and often do cause extensive surface disruption on turf mowed at greens height. Two rates (1x and 2x of product label rate) of Crusade (fonophos), Sevin (carbaryl), DeltaGard (deltamethrin), and Chipco Choice (fipronil), were applied on September 28, 2001 on an SR1020 creeping bentgrass green. Percent rove beetle control was nearly 100% for DeltaGard at 9, 15 and 32 days after treatment, regardless of rate. Crusade had nearly 100% control at either rate at 9 days after treatment, which decreased slightly to 90-93% control by 15 days after treatment. Deltamethrin maintained 95% and 98% control at the 1x and 2x rates respectively, at the close of the test (32 DAT). Crusade maintained 93% and 98% control at the 1x and 2x rates at 32 DAT. Chipco Choice had a maximum control of 24% at 7 DAT when applied at the 1x rate, and a maximum control of 57% at 32 DAT when applied at the 2x rate. Sevin provided low levels of control which peaked at 53% at the 1x rate at 9 DAT, which decreased immediately afterwards. Delta-Gard and Crusade provided excellent control levels of rove beetles on SR1020 bentgrass greens.

Rapid blight is a new disease of cool season turf grasses that has occurred on several golf courses in Arizona over the past five years. It is now known to be caused by a Labyrinthula sp., an organism in a group referred to as the marine slime molds. A trial was conducted in fall 2002 to evaluate efficacy of selected fungicides for control of rapid blight at a golf course in central Arizona with a previous history of disease. Plots were established in October 2002 on a practice green on which Bermuda was overseeded with Poa trivialis. Treatments included Compass, Insignia, Fore, Eagle and Aqueduct in various combinations and application dates. Disease symptoms appeared several days after the first mowing and continued for over three months. Results indicate that both pre- and post-plant applications of Fore and post-plant applications of Insignia and Compass gave good control. The best results were obtained with the treatment of Fore combined with Compass that included a pre-plant application of Fore, or with post-plant application of Insignia.

A number of turfgrasses were screened in the greenhouse and laboratory for susceptibility to Labyrinthula terrestris, a new turfgrass pathogen that causes rapid blight of cool season turfgrasses. Salt tolerant varieties and warm season grasses such as Bermuda grass, tufted hairgrass, inland saltgrass, centipede grass, seashore paspalum and kikuyugrass were not susceptible; cool season grasses such as velvet bentgrass, annual ryegrass, perennial ryegrass, annual bluegrass, Kentucky bluegrass, and rough bluegrass were very susceptible.

Rapid blight disease is a potentially devastating disease on cool season overseed turfs when irrigated with saline water. A two year test was conducted on a closely mowed Tifgreen bermudagrass turf which was infected with visual symptoms of necrotic patches of turf, and various degrees of blighting. The test included a broad representation of turf species for overseeding in an effort to (1) determine selected specie/cultivar susceptibility and disease expression to rapid blight in the field and (2) survey and assess the association of laboratory isolate detection from field sampling, with disease occurrence and severity of expression of field maintained overseed turf. Over a two year period, Rapid blight, caused by Labyrinthula terrestris was capable of infesting most cool season grasses in this test. In year one, Dawson CRF, SRX 555 slender creeping red fescue, and SR 105210 slender creeping red fescue showed no positive lab detection results from field plots. In year two (2003-2004), only SRX 555 SLQ had only 1 plot known to carry Labyrinthula throughout the main infestation season. In year two, essentially all turf plots showed some symptomology of disease expression. This was confirmed by lab identification. Tiller infection rates varied from 2% to 80% infection in the lab from field samples. The relationship between tiller infection rates and field plot disease expression was determined by Pearson’s product and Spearman Rank correlation coefficients. Field plot disease scores were correlated with percent tiller infection rates, R² = -0.56 plot basis, and R² = –0.71 treatment mean basis, respectively. Spearman Rank correlation coefficients were R² =; -0.62 on a plot basis, and R² =–0.78 based on treatment means Agreement between the disease condition (yes/no) vs. lab findings (positive/negative) occurred on 51 of 59 plot cases, and was significant compared to chance alone occurrences. Over two years, entries which had low disease scores included Fult’s alkali grass, Dawson creeping red fescue, SRX 555 SLQ slender creeping red fescue, SR 5210 slender creeping red fescue, and Providence creeping bentgrass. Over two years, entries which produced high field disease rating scores included SR 3100 Hard fescue, TransEze intermediate ryegrass, SR 4400 perennial ryegrass, SR 7200 velvet bentgrass, SR 7100 colonial bentgrass, Sabre and Laser Poa trivialis, and Redtop.

Dierama is a genus of plants with a potential to be developed as ornamental plants. It falls under the Iridaceae family and comprises of 44 species. Dierama erectum Hilliard, an attractive species with horticultural potential is mainly found in rough wet grasslands. Its corms are used for enemas and treating stomach ailments in southern African traditional medicine. Due to its habitat transformation by afforestation and the exploitation of its underground parts (corms) in traditional medicine, this plant is among the most vulnerable and rare species within its genus. Seed parasitism by Urodon lilli also hampers its conventional propagation. The increase in demand for ornamental and medicinal plants increases pressure on wild plant populations. Micropropagation is a useful tool for clonal propagation of plants as it does not only help in alleviating pressure on wild plants but an effective micropropagation protocol could also provide a foundation for plant genetic transformation, which could result in the development and introduction of new ornamental varieties into commercial markets. This research was aimed at developing a micropropagation protocol for D. erectum to ensure readily available source material for medicinal and horticultural use as well as serving as an alternative for its conservation. Seed decontamination and germination were successful when 0.2% HgCl2 or 2.5% NaOCl + 1% Benlate® were used. However, for safety reasons, 2.5% NaOCl + 1% Benlate® was used in all subsequent experiments. The shoot regenerative capacity of leaf, hypocotyl and root explants obtained from in vitro germinated seedlings was evaluated by culturing them individually on MS medium supplemented with various concentrations of BA. Only hypocotyl explants produced adventitious shoots. Since no shoots or callus was produced from leaf and root explants, hypocotyl explants were used in the development of a micropropagation protocol. Different types and concentrations of cytokinins (BA, mT, KIN and Z) with or without NAA were evaluated for their effect on adventitious shoot production. Maximum shoot number per explant (4.20 ±0.51) was obtained in MS medium supplemented with 1.0 ìM Z after 8 weeks. This was followed by a combination of KIN (2.0 ìM) and NAA (0.5 ìM) resulting in a production of 3.67 ± 0.81 shoots per explant. For BA treatments, the highest shoot multiplication (3.20 ± 0.22 shoots per explant) was achieved when 2.0 ìM was combined with 1.0 ìM NAA. mT gave maximum shoot production (3.09 ± 0.99 shoots per explant) when 2.0 ìM mT was combined with 2.0 ìM NAA. The effects of photoperiod and light intensity were investigated for the purpose of optimizing shoot multiplication. An average of 12.73 ± 1.03 shoots per explant were obtained after 8 weeks from shoots grown in 16 h light at a 100 ìmol m-2 s-1 light intensity. The 24 h light treatments and a light intensity lower than 100 ìmol m-2 s-1 negatively affected growth and regeneration of D. erectum. These results highlighted the need for evaluating environmental conditions when developing micropropagation protocols. Corm induction experiments were done with the intention of facilitating acclimatization of D. erectum ex vitro. Various concentrations of ancymidol, activated charcoal and sucrose did not promote in vitro corm formation, thus auxins (IAA, IBA and NAA) were tested for their efficiency in rooting. Plants rooted successfully after 8 weeks on MS medium supplemented with 1.0 ìM IBA, yielded the longest roots (4.63 ± 0.70 cm) and an average root number of 2.73 ± 0.40. All NAA treatments resulted in stunted roots. Plants grown in vitro were potted in trays containing a 1:1 ratio of soil: vermiculite and placed in the mist house for 2 weeks. They were then transferred to the greenhouse for further acclimatization. After 2 months, plants had formed corms. The largest corms (0.45 ± 0.026 cm in diameter) were found in plants pre-treated with 0.5 ìM IBA. Maximum plant survival percentage (73%) was also associated with this treatment. A successful micropropagation system for Dierama erectum was therefore developed. The utilisation of this protocol can yield about 15137 plants from one explant in a year. This will expand our existing knowledge about micropropagation of plants in the genus Dierama and will be useful in the conservation of this species. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.

Many plants are not commercially produced due to a lack of accessible information on their horticultural requirements and landscape potential. Members of the Legume Family (Leguminosae) are often conspicuous components of the vegetation of arid and semi-arid subtropical regions. Many of these plants are suitable for landscaping use in areas suited to their cultivation. Coursetia glandulosa, Erythrina flabelliformis, Eysenhardtia orthocarpa, Haematoxylon brasiletto, Lysiloma watsonii, Pithecellobium mexicanum, and Sophora arizonica are woody legumes native to the Sonoran Desert region which offer a variety of form, texture, color and function. All of these plants grow readily from scarified seed. E. flabelliformis and E. orthocarpa are easy to propagate from stem cuttings. Some irrigation is necessary for establishment and reasonable growth in the landscape. Maintenance and pests are minimal. Freezing temperatures are the primary limiting factor to several of the plants. S. arizonica is slow growing and is prone to rot in the nursery.

As ornamental container nurseries face diminishing water allocations, many are looking to automated irrigation solutions to increase their water application efficiency. This thesis presents the findings of a study conducted at a commercial container nursery to determine 1) whether a capacitance or load cell sensor was better suited for monitoring volumetric water content in the substrate; 2) if the actual irrigation distribution conformed to the expected pattern, how uniform were the weights of plants, and how these combined with plant canopy affected the leaching fraction; and 3) the reliability of the wireless network used to transmit the data to a central database. It was found that 1) the load cells outperformed the capacitance-based sensors because the load cells took an integrated measure; 2) the actual irrigation pattern followed the expected pattern, the variation of irrigation sections were low (C.V. = 0.06) and similar (C.V. ranging from 0.029 to 0.12), and unpruned plant canopies produced greater leaching fraction than pruned canopies (P < 0.18); and 3) wireless network transmission reliability was low (75.2%), suggesting that the system was not suitable for real-time irrigation control, but was sufficient for calculating irrigation length and monitoring net effective irrigation application and evapotranspirative consumption. / Graduation date: 2012