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Sally M. Stewart-wade - One of the best experts on this subject based on the ideXlab platform.
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Plant pathogens in recycled irrigation water in commercial Plant Nurseries and greenhouses: their detection and management
Irrigation Science, 2011Co-Authors: Sally M. Stewart-wadeAbstract:With water conservation and reuse a priority for communities worldwide, recycling irrigation water in commercial Plant Nurseries and greenhouses is a logical measure. Plant pathogenic microorganisms may be present in the initial water source, or may accrue and disperse from various points throughout the irrigation system, constituting a risk of disease to irrigated Plants. The continual recycling of this water is exacerbating this Plant disease risk. Accurate and timely detection of Plant pathogenic propagules in recycled irrigation water is required to assess disease risk. Both biological and economic thresholds must be established for important Plant-pathosystems. Plant pathogens in recycled irrigation water can be managed by a variety of treatment methods that can be arranged in four broad categories: cultural, physical, chemical, and biological. An integrated approach using one or more techniques from each category is likely to be the most effective strategy in combating Plant pathogens in recycled irrigation water.
Kurt Lamour - One of the best experts on this subject based on the ideXlab platform.
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co occurrence and genotypic distribution of phytophthora species recovered from watersheds and Plant Nurseries of eastern tennessee
Mycologia, 2010Co-Authors: Jon Hulvey, Daniel Gobena, Ledare Finley, Kurt LamourAbstract:In 2008 statewide surveys of symptomatic foliage of nursery Plants from Tennessee resulted in isolation of 43 isolates of Phytophthora spp. This sample set includes four described species (P. citrophthora, P. citricola, P. nicotianae, P. syringae), and a provisional species of Phytophthora ('P. hydro- pathica'). At the same time a stream-baiting survey was initiated to recover Phytophthora from eight water- sheds in eastern Tennessee, some of which are near Plant Nurseries. Baiting was accomplished by sub- merging healthy Rhododendron leaves approximately 1 wk and isolation onto selective media. Six baiting periods were completed, and in total 98 Phytophthora isolates and 45 isolates of Pythium spp. were recov- ered. Three described species (P. citrophthora, P. citricola and P. irrigata) and the provisional species 'P. hydropathica' were obtained as well as three undescribed Phytophthora taxa and Pythium litorale. Isolates from both surveys were identified to species with morphology and the internal transcribed spacer (ITS) sequence. Isolates from species co-occurring in streams and Nurseries (P. citricola, P. citrophthora and 'P. hydropathica') were characterized further with amplified fragment length polymorphism (AFLP) analyses and mefenoxam tolerance assays. Isolates representing a putative clonal genotype of P. citricola were obtained from both environmental and nursery sample sets.
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short title phytophthora co occurrence and genotypic distribution of phytophthora species recovered from watersheds and Plant Nurseries of eastern tennessee
2010Co-Authors: Jon Hulvey, Daniel Gobena, Ledare Finley, Kurt LamourAbstract:In 2008 statewide surveys of symptomatic foliage of nursery Plants from Tennessee resulted in isolation of 43 isolates of Phytophthora spp. This sample set includes four described species (P. citrophthora, P. citricola, P. nicotianae, P. syringae), and a provisional species of Phytophthora ('P. hydropathical'). At the same time a stream-baiting survey was initiated to recover Phytophthora from eight watersheds in eastern Tennessee, some of which are near Plant Nurseries. Baiting was accomplished by submerging healthy Rhododendron leaves approximately 1 wk and isolation onto selective media. Six baiting periods were completed, and in total 98 Phytophthora isolates and 45 isolates of Pythium spp. were recovered. Three described species (P. citrophthora, P. citricola and P. irrigata) and the provisional species 'P. hydropathica' were obtained as well as three undescribed Phytophthora taxa and Pythium litorale. Isolates from both surveys were identified to species with morphology and the internal
Ted Whitwell - One of the best experts on this subject based on the ideXlab platform.
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effect of delayed irrigation on isoxaben and oryzalin runoff from a container nursery
Weed Science, 2003Co-Authors: Jeanne Briggs, Ted Whitwell, Melissa B RileyAbstract:Abstract The presence of herbicides in runoff water after application to container Plant Nurseries warrants investigation of methods to reduce the amount of runoff. During the summer of 2000, field research was conducted at a commercial nursery to determine the effect of a delay in irrigation after herbicide application on herbicide levels in runoff water. Two studies were conducted in June and August. Isoxaben and oryzalin were sprayed on container Plants in production beds at a rate of 1.4 and 2.9 kg ai ha−1, respectively. Treatments were pulse irrigated either immediately or 24 h after herbicide application. Pulse irrigation consisted of three 30-min irrigation cycles, with a 90-min rest between cycles, that supplied a total of 1.8 to 2.0 cm of water. Runoff samples were collected from both treatments after 0, 15, and 30 min of runoff flow from each pulse cycle for 3 consecutive d of pulse irrigation. The maximum isoxaben detected in June for the immediate irrigation treatment was 2.2 μg ml−1. The maxi...
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formulation effects on isoxaben and trifluralin in runoff water from container Plant Nurseries
Weed Science, 2002Co-Authors: Jeanne Briggs, Ted Whitwell, Thomas R Fernandez, Melissa B RileyAbstract:Abstract Sprayable and granular formulations of isoxaben and trifluralin were applied to container Plant nursery beds to determine formulation effects on herbicide runoff and weed control. In 1998 herbicide application was followed by 0.8 cm of irrigation delivered in 60 min, and runoff water samples were collected on the day of application (DOA). The highest concentrations of isoxaben and trifluralin detected in runoff water were 0.50 and 0.15 μg ml−1, respectively. Total isoxaben in runoff water was greater from the granular than from the sprayable formulation, but no differences attributable to formulation were detected for trifluralin. In 1999 herbicide application was followed by irrigation applied in three pulse cycles of 30 min each (0.8 cm per cycle). Runoff water samples were collected daily through 2 d after herbicide application (DAA). The highest herbicide concentrations were found in the first runoff sample on the DOA. Isoxaben was detected at 1.6 μg ml−1 from both formulations, and triflural...
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phytotoxicity uptake and distribution of 14c simazine in acorus gramenius and pontederia cordata
Weed Science, 2000Co-Authors: P C Wilson, Ted Whitwell, Stephen J KlaineAbstract:Abstract Phytoremediation depends on the ability of Plants to tolerate and assimilate contaminants. We have been interested in the use of common ornamental Plants to ameliorate the effects of pesticide waste on golf courses and ornamental Plant Nurseries. This research characterized the interaction between two ornamentals, Acorus gramenius and Pontederia cordata, and the herbicide simazine. Simazine tolerance levels for the ornamentals were determined by exposing Plants to 0, 0.01, 0.03, 0.1, 0.3, 1.0, or 3.0 mg L−1 in aqueous nutrient media for 7 d. Response endpoints included fresh weight gains for both species after 7 d exposure and 7 d postexposure. Quantum efficiency of P. cordata was also measured using dark-adapted (Fv/Fm) and light-adapted (fluorescence yields) Plants. Simazine uptake and distribution within each Plant was determined by exposing Plants to [14C]-simazine in nutrient media (0.24 mg L−1) for 1, 3, 5, or 7 d. Plant tissues were combusted and analyzed by liquid scintillation counting. ...
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phytotoxicity uptake and distribution of 14c simazine in canna hybrida yellow king humbert
Environmental Toxicology and Chemistry, 1999Co-Authors: Chris P Wilson, Ted Whitwell, Stephen J KlaineAbstract:Phytoremediation depends on the ability of Plants to tolerate and assimilate contaminants. We have been interested in the use of common ornamental Plants to ameliorate the impacts of pesticide waste on golf courses and ornamental Plant Nurseries. This research characterized the interaction between an ornamental, Canna hybrida ‘Yellow King Humbert,’ and the herbicide simazine. Simazine tolerance levels for C. hybrida were determined by exposing Plants for 7 d to 0, 0.01, 0.03, 0.1, 0.3, 1.0, or 3.0 mg-simazine/L aqueous nutrient media. Response endpoints included fresh mass production after 7 d of exposure and 7 d postexposure and quantum efficiency using dark-adapted and light-adapted Plants. Simazine uptake and distribution within the Plant was determined by exposing Plants to 2.02 μCi [14C]simazine in nutrient media (0.242 mg/L) for 1, 3, 5, or 7 d. Plant tissues were combusted and analyzed by liquid scintillation counting. Fresh mass production was reduced 66 and 78% for Plants exposed to 1.0 and 3.0 mg/L, respectively. Photosynthetic efficiency measured in dark-adapted Plants was reduced 34 and 60% at the same respective concentrations, whereas photosynthetic efficiency measured in light-adapted Plants was reduced 76 and 92%, respectively. Simazine activity in solution was reduced 80% over 7 d. By day 7, simazine (and/or an impurity) was distributed throughout the Plant, but predominantly occurred in the leaves. Uptake of simazine was correlated with water uptake throughout the 7 d. These results suggest that C. hybrida may be a good candidate for incorporation into a phytoremediation scheme for simazine.
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remediation of herbicides in runoff water from container Plant Nurseries utilizing grassed waterways
Weed Technology, 1999Co-Authors: Jeanne Briggs, Ted Whitwell, Melissa B RileyAbstract:The ability of grassed waterways to remediate herbicide loads in runoff water was evaluated using simulated and on-site nursery research. Isoxaben plus oryzalin and isoxaben plus trifluralin were applied to model grassed (zoysiagrass or 'Tifway 10' hybrid bermudagrass) and nongrassed, metal and clay loam waterways, and runoff samples were collected. Grassed waterways reduced runoff volume an average of 47% and herbicide residues an average of 56% compared to nongrassed waterways. The smallest herbicide residues were from the clay/grass waterways. In a nursery study, isoxaben and trifluralin were applied to containerized landscape Plant production beds. Overhead irrigation was applied and runoff water was channeled into either a clay/gravel waterway or a hybrid bermudagrass waterway. Samples were collected for 22 d following application. Isoxaben persisted through 15 d after application. Trifluralin was detected through 2 d after application. Total isoxaben recovered from the clay/gravel waterway was 32% of applied, and total trifluralin recovered was 0.9% of applied. The grass waterway reduced residues of isoxaben and trifluralin by 22 and 66%, respectively, compared to the clay/gravel waterway. Nomenclature: Isoxaben, N-[3-(1-ethyl-1-methylpropyl)-5-isoxazolyl]-2,6-dimethoxybenzamide; oryzalin, 4-(dipropylamino)-3,5-dinitrobenzensulfonamide: trifluralin, 2,6-dinitro-N,N-dipropyl-4-(trifluoromethyl)benzenamine; zoysiagrass, Zoysia japonica Steud. Meyer'; hybrid bermudagrass, Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davy.
Heike Knicker - One of the best experts on this subject based on the ideXlab platform.
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recycling pyrolyzed organic waste from Plant Nurseries rice production and shrimp industry as peat substitute in potting substrates
Journal of Environmental Management, 2021Co-Authors: Marco Nocentini, Marco Panettieri, Jose Maria Garcia De Castro Barragan, Giovanni Mastrolonardo, Heike KnickerAbstract:Abstract Organic waste from greens of tomato Plants, gardening substrate, rice husks and shrimp-derived chitin were pyrolyzed at 400 °C and 500 °C for 3 h, with the aim to elucidate the feasibility of using such products as replacement of peat in soilless gardening substrates. Characterization of the carbonized organic matter (COM) and the gardening substrate indicated that neither the peat nor the COMs provided the recommended levels of nutrients for the cultivation of tomato Plants, although improvements could be obtained using COM/substrate mixtures. The toxicity thresholds for Zn were exceeded significantly by the COMs of the tomato greens and high boron levels were found for all the COMs except for those derived from chitin. In a 40-days pot experiment, germination and development of tomato seeds and Plants (Solanum lycopersicum L.) were tested on COM/peat mixtures at 30%, 60% and 100% COM substitution rate. The lack of seed germination on the mixtures with COM from tomato greens is best explained with the high salinity of the COM. Best Plant growth was obtained with COM from chitin at 60%, most likely because its high N content satisfied best the N-needs of the growing tomato Plants without increasing the pH of the growing media. Moreover, an increase of water retention was evidenced for COM/substrate mixtures. Although the use of COM from chitin and rice husks showed promising results, the proposed recycling of organic waste from agriculture or fishery as soilless gardening substrate requires the development of formulations of COM/peat/and added nutrients with ready-to-use characteristics to increase its feasibility.
D A Schisler - One of the best experts on this subject based on the ideXlab platform.
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the occurrence and pathogenicity of rhizoctonia fungi in south australian Plant Nurseries
Fungal Biology, 1994Co-Authors: D A Schisler, Stephen M. Neate, G. MasuharaAbstract:Potting mixes and Plants exhibiting symptoms of root disease were collected from 30 Nurseries or potting mix suppliers in South Australia. Thirty-nine isolates of Rhizoctonia were obtained from 11 sampling locations by isolating from diseased Plants, Planting media, or by isolating from the roots of bait seedlings (zinnia, brussels sprouts, radish, bell pepper, wheat and ornamental lupin) grown in the Planting media. Thirty-five isolates were binucleate and four were multinucleate. Binucleate isolates anastomosed with known groups AG-A, AG-I, AG-K or CAG 5 and 10 were not able to be placed in any known group. Multinucleate isolates belonged to AG-2-1 and AG-4. Certain AG-4 multinucleate isolates reduced the growth of wheat or bell pepper while certain binucleate isolates decreased the growth of wheat or increased the growth of bell pepper. Although multinucleate Rhizoctonia fungi can cause severe disease of bedding Plants, it is difficult to predict such damage due to the influence of potting mix edaphic factors and variability in pathogenicity of the isolates present.
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Characteristics of some Rhizoctonia spp. from South Australian Plant Nurseries
Mycological Research, 1994Co-Authors: G. Masuhara, Stephen M. Neate, D A SchislerAbstract:Forty-nine Rhizoctonia isolates were obtained from nursery Plants, potting mix, vegetable seedlings and bedding Plants in South Australia. Of these isolates, 75% were binucleate Rhizoctonia and 25% were multinucleate. Anastomosis tests showed that all of the multinucleate isolates were either Rhizoctonia solani AG-2-1 or AG-4 and that the binucleate Rhizoctonia belonged to either AG-F, AG-I, AG-K and CAG-5 or to four other groups of isolates which did not anastomose with the known isolates tested. Teleomorphs of 14 isolates were induced and were identified as Thanatephorus cucumeris, Ceratobasidium cornigerum, C. pseudocornigerum and two unknown species Ceratobasidium . Extracellular pectic enzyme patterns were not useful in determining likely anastomosis groups for the binucleate Rhizoctonia .
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binucleate rhizoctonia isolates control damping off caused by pythium ultimum var sporangiiferum and promote growth in capsicum and celosia seedlings in pasteurized potting medium
Soil Biology & Biochemistry, 1993Co-Authors: A R Harris, D A Schisler, M H RyderAbstract:Abstract Eight isolates of binucleate Rhizoctonia spp, from South Australian Plant Nurseries and potting mix suppliers, were screened for ability to control damping-off disease caused by Pythium ultimum var. sporangiiferum . The screening was by two bioassays on seedlings of Capsicum annuum grown in a pasteurized potting medium in a glasshouse or controlled environment growth chamber. Three isolates reduced damping-off at least as much as the fungicide propamocarb. The fungicides tolclofos-methyl and benomyl did not reduce disease or increase shoot weights. In other glasshouse experiments, binucleate Rhizoctonia isolates BNR1 and BNR2 reduced damping-off in Capsicum seedlings more as doses of each antagonist were increased. In pasteurized potting medium without added pathogens, isolates BNR1 and BNR2 increased dry weights of Capsicum shoots per punnet by 33 and 24%, respectively, compared with only 13% for the bacterium, Bacillus subtilis A 13. Isolates BNR1 and BNR2 completely controlled damping-off in seedlings of Celosia argentea , but propamocarb and B. subtilis did not.