scholarly journals Effects of Container Bases on the Spread of Meloidogyne incognita in a Hawaiian Ornamental Nursery

Plant Disease ◽  
1997 ◽  
Vol 81 (6) ◽  
pp. 607-613 ◽  
Author(s):  
M. P. Ko ◽  
D. P. Schmitt ◽  
M. Saxby
Keyword(s):  
Meloidogyne Incognita ◽  
Bare Soil ◽  
Control Treatment ◽  
Nursery Ground ◽  
Indicator Plant ◽  
Bare Ground ◽  
Concrete Masonry ◽  
Splash Dispersal ◽  
Rain Splash ◽  
Heavy Rains

The influence of container bases on nematode spread from infested pots or ground in an ornamental foliage nursery was investigated with Meloidogyne incognita as the test nematode and cowpea as the indicator plant. The container bases examined were black cloth, concrete masonry blocks, gravel, crushed cinders, and bare ground. Masonry blocks raised 46 cm above ground (raised bench) served as the control treatment. Under the standard nursery practice of irrigation by rainfall and supplemental overhead sprinkler, nematodes spread from contaminated pots or ground to adjacent nematode-free pots on all tested container bases. Incidence of spread, measured as the percentage of nematode-free pots that became contaminated, increased over time and occurred more extensively from ground to pot than from pot to pot. Ground to pot spread increased rapidly following heavy rains, indicating rain was an important contributing factor. On the M. incognita-infested nursery ground, the nematode was found more frequently associated with weeds than with bare soil, suggesting that weeds were important reservoirs of nematode inoculum for rain-splash dispersal. Placement of containers on a raised bench was more effective than on any of the unraised container bases in preventing the ground to pot spread.

scholarly journals Effects of a Cover Crop on Splash Dispersal of Colletotrichum acutatum Conidia

1998 ◽  
Vol 88 (6) ◽  
pp. 536-543 ◽  
Author(s):  
N. Ntahimpera ◽  
M. A. Ellis ◽  
L. L. Wilson ◽  
L. V. Madden
Keyword(s):  
Cover Crop ◽  
Bare Soil ◽  
Selective Medium ◽  
Planting Density ◽  
Colletotrichum Acutatum ◽  
Type Model ◽  
Parameter Estimates ◽  
Diffusion Type ◽  
Tall Grass ◽  
Splash Dispersal

A rain simulator, with generated rains of 11 and 30 mm/h, was used to determine the effect of a cover crop or intercrop on the splash dispersal of Colletotrichum acutatum conidia. Dispersal through sudangrass, which can be used as a ‘living mulch’, was tested at two planting densities (140 or 280 kg/ha) and two heights (5 and 20 cm) and compared with a control consisting of a bare soil. Dispersal of C. acutatum conidia was assessed by counting colonies formed from spore-bearing splash droplets deposited in sheltered petri plates containing a selective medium. Both a cover crop and rain intensity significantly affected splash dispersal as measured by the interpolated total number of colonies (denoted by Σ) from 0 to 72 cm from the inoculum source and in a time span of 61 min of generated rain (P < 0.001). However, there was no significant interaction of cover crop and intensity (P > 0.90). Dispersal with a 30-mm/h rain was higher than dispersal with a 11-mm/h rain, and presence of a cover crop significantly reduced dispersal compared with bare soil (P < 0.001). Of the treatments with sudangrass, cover crop planting density did not affect dispersal overall, but there was greater spore dispersal with the taller sudangrass at the higher planting density, due in part to the higher rate of water splashing with the tall grass compared with the short grass. Spore deposition in the petri plates could be functionally related to distance and time using a diffusion-type model, and parameter estimates could be used to explain the effects of cover crop on Σ. Although the relationship between cover crop properties and splash dispersal is complex, results show the potential beneficial effects of the cover crop on disease management.

scholarly journals Cyclo(l-Pro–l-Leu) of Pseudomonas putida MCCC 1A00316 Isolated from Antarctic Soil: Identification and Characterization of Activity against Meloidogyne incognita

Molecules ◽  
2019 ◽  
Vol 24 (4) ◽  
pp. 768 ◽  
Author(s):  
Yile Zhai ◽  
Zongze Shao ◽  
Minmin Cai ◽  
Longyu Zheng ◽  
Guangyu Li ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Pseudomonas Putida ◽  
Meloidogyne Incognita ◽  
High Performance ◽  
Larval Mortality ◽  
Control Treatment ◽  
Hatching Rate ◽  
Antarctic Soil ◽  
Egg Hatching ◽  
Flight Mass Spectrometry

Pseudomonas putida MCCC 1A00316 was originally isolated from an Antarctic soil and has demonstrated potential nematicidal activity. Thus, it has promising applications for the biological control of Meloidogyne incognita. The larval mortality and egg-hatching inhibition rates of M. incognita will increase with the rising concentration of culture filtrates of P. putida MCCC 1A00316 and the duration of exposure. Thus, this study aimed to separate, purify, and identify nematicidal compounds from P. putida MCCC 1A00316 and to validate their anti-M. incognita activities. Compounds were purified through silica gel column chromatography and thin-layer chromatography combined with high-performance liquid chromatography (HPLC). Structural identification was conducted through liquid chromatography time-of-flight mass spectrometry, 1H nuclear magnetic resonance (NMR) spectroscopy, 13C-NMR, and Marfey’s method. The isolated compounds were identified as cyclo(l-Pro–l-Leu) on the basis of the results of the above analyses and previously reported data. The effects of various concentrations of cyclo(l-Pro–l-Leu) on the mortality rates of second-stage juveniles (J2) of M. incognita were investigated. Results showed that HPLC-purified cyclo(l-Pro–l-Leu) displayed nematicidal activities. The mortality rate of M. incognita J2 reached 84.3% after 72 h of exposure to 67.5 mg/L cyclo(l-Pro–l-Leu). The lowest egg-hatching rate (9.74%) was observed after 8 days of incubation with 2000 mg/L cyclo(l-Pro–l-Leu). An egg-hatching rate of 53.11% was obtained under the control treatment (sterile distilled water). However, cyclo(l-Pro–l-Leu) did not elicit chemotaxis activity to M. incognita. This is the first work to investigate the anti-M. incognita characteristics of cyclo(l-Pro–l-Leu).

scholarly journals Rain Splash Dispersal of Gibberella zeae Within Wheat Canopies in Ohio

2004 ◽  
Vol 94 (12) ◽  
pp. 1342-1349 ◽  
Author(s):  
P. A. Paul ◽  
S. M. El-Allaf ◽  
P. E. Lipps ◽  
L. V. Madden
Keyword(s):  
Flux Density ◽  
Soil Surface ◽  
Selective Medium ◽  
Gibberella Zeae ◽  
Spore Density ◽  
Rain Intensity ◽  
Head Blight ◽  
Splash Dispersal ◽  
Rain Splash ◽  
Maize Kernels

Rain splash dispersal of Gibberella zeae, causal agent of Fusarium head blight of wheat, was investigated in field studies in Ohio between 2001 and 2003. Samplers placed at 0, 30, and 100 cm above the soil surface were used to collect rain splash in wheat fields with maize residue on the surface and fields with G. zeae-infested maize kernels. Rain splash was collected during separate rain episodes throughout the wheat-growing seasons. Aliquots of splashed rain were transferred to petri dishes containing Komada's selective medium, and G. zeae was identified based on colony and spore morphology. Dispersed spores were measured in CFU/ml. Intensity of splashed rain was highest at 100 cm and ranged from 0.2 to 10.2 mm h-1, depending on incident rain intensity and sampler height. Spores were recovered from splash samples at all heights in both locations for all sampled rain events. Both macroconidia and ascospores were found based on microscopic examination of random samples of splashed rain. Spore density and spore flux density per rain episode ranged from 0.4 to 40.9 CFU cm-2 and 0.4 to 84.8 CFU cm-2 h-1, respectively. Spore flux density was higher in fields with G. zeae-infested maize kernels than in fields with maize debris, and generally was higher at 0 and 30 cm than at 100 cm at both locations. However, on average, spore flux density was only 30% lower at 100 cm (height of wheat spikes) than at the other heights. The log of spore flux density was linearly related to the log of splashed rain intensity and the log of incident rain intensity. The regression slopes were not significantly affected by year, location, height, and their interactions, but the intercepts were significantly affected by both sampler height and location. Thus, our results show that spores of G. zeae were consistently splash dispersed to spike heights within wheat canopies, and splashed rain intensity and spore flux density could be predicted based on incident rain intensity in order to estimate inoculum dispersal within the wheat canopy.

Reduction of fungal disease spread in cultivar mixtures: Impact of canopy architecture on rain-splash dispersal and on crop microclimate

2017 ◽  
Vol 246 ◽  
pp. 154-161 ◽  
Author(s):  
Tiphaine Vidal ◽  
Anne-Lise Boixel ◽  
Brigitte Durand ◽  
Claude de Vallavieille-Pope ◽  
Laurent Huber ◽  
...  
Keyword(s):  
Fungal Disease ◽  
Disease Spread ◽  
Canopy Architecture ◽  
Splash Dispersal ◽  
Rain Splash ◽  
Cultivar Mixtures

scholarly journals STRAW MULCH UNDER STRAWBERRIES REDUCES EROSION AND HAILDAMAGE

HortScience ◽  
1993 ◽  
Vol 28 (4) ◽  
pp. 274A-274
Author(s):  
Julia Whitworth
Keyword(s):  
Bare Ground ◽  
Plastic Mulch ◽  
Straw Mulch ◽  
Early Afternoon ◽  
Heavy Rains

In September of 1991, 1.1 m × 20 cm raised beds were built near Lane, OK. The beds were covered with straw or woven plastic mulch, or were left uncovered. Heavy rains in October left the uncovered beds about 20 cm wide × 13 cm tall. A gully was formed at the end of this field, and soil was deposited across several beds. Strawberry plants were set into all beds in mid-February 1992. At this time, the straw-mulched beds, although settled into an inverted “V” shape, were still about 1 m wide and about 18 cm tall. A very intense hail and rain storm struck the fields on May 13. Most of the hail was about 1.3 cm in diameter. The hail fell for about 30 minutes in early afternoon. The hail was accompanied by about 12.7 cm of rain. The strawberry plants on the woven plastic mulch were almost completely destroyed. The strawberry plants on bare ground were severely damaged by the hail, and their roots were often washed out of the ground. About 85 to 90 percent of these plants died. Strawberry plants on the straw-mulched beds appeared to be less damaged by the hail than other plants, and were not washed out of the ground. About 95% of these plants survived.

scholarly journals Effects of Saline Water and Two Types of Plastic Mulch on Physiology and Yield of Bell Pepper Plants

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 852C-852
Author(s):  
Dagobiet Morales-Garcia* ◽  
Katrine A. Stewart
Keyword(s):  
Stomatal Conductance ◽  
Water Consumption ◽  
Fruit Development ◽  
Saline Water ◽  
Bare Soil ◽  
Control Treatment ◽  
Plastic Mulch ◽  
Marketable Yield ◽  
Control Value ◽  
Bell Peppers

In order to examine the effects of saline water (0.2, 1.5, 4.0, 6.5 and 9.0 dS·m-1) without or with plastic mulch (black or green infrared transmitting) on the physiology and yield of bell peppers (Capsicum annuum L. var. Red Night), plants were drip irrigated and grown in greenhouse conditions. Salinity did not significantly decrease the rate of photosynthesis until fruit set after which irrigation with 6.5 and 9.0 dS·m-1 reduced rates by 35%-38% and during fruit development by 50% compared with the control treatment. Plants receiving 4.0 dS·m-1 had significantly lower (30%) photosynthetic rates than the control during fruit development. Stomatal conductance decreased as the rate of salinity increased which in turn affected transpiration. No consistent differences in photosynthesis, stomatal conductance and transpiration rates were obtained with or without plastic mulch. The marketable yield was negatively affected as salinity increased having being reduced by 17%, 64%, 96%, and 100% for saline treatments compared with the control. The number of fruit of fruit per plant was significantly lower at rates of 4.0 dS·m-1 or higher. No significant differences were detected among plastic mulches and non-mulch condition in marketable yield and number of fruits. Water consumption decreased as salinity level increased with decreases of 11%, 20%, 38%, and 52% of the control value. Mulching the soil reduced water consumption by 30% compared with bare soil.

scholarly journals Efecto de la cobertura plástica y el encalado en chile, en el sureste de México.

2006 ◽  
Vol 10 (2) ◽  
pp. 91
Author(s):  
Roberto Zetina ◽  
Daniel E Uriza
Keyword(s):  
Experimental Design ◽  
Soil Ph ◽  
Management System ◽  
Total Yield ◽  
Fruit Yield ◽  
Significant Response ◽  
Control Treatment ◽  
High Input ◽  
Black Plastic ◽  
Heavy Rains

In the south of Veracruz, Mexico, 5000 ha of chili are cultivated annually in acids soils and with a low CIC. The sandy texture of the soil and the low rainfalls in the last three months of the year coincides with the productive stage of plantations established after the heavy rains of june and july. The objective of this study was to evaluate under rain conditions the effect of lime and plastic covering on the acidity of a recently exposed soil to the cultivation and production of “serrano” chili under a high input management system. The experimental design was one of divided parcels with three repetitions: in the big parcels with four dose of liming (0, 0.5, 1 and 3 t/ha of CaCO3) and in the small parcels two plastic coverings (black plastic/ white and plastic black) and a control treatment without covering. The total yield of fruit showed a significant response to the black/white plastic covering and to the interaction lime (1 ton/ha)- (black/ white plastic covering)obtaining increments of the 40% to 82% respectively. The fruit yield did not show a significant response to the lime. Treatments using lime increased the soil pH from 5.2 to 5.6 and the levels of interchangeable bases from 40 to 54 ppm K, 882- 1146 ppm Ca and 205-192 ppm of Mg.

Where do spores go? Rain-splash patterns using surrogate dye.

2017 ◽  
Vol 70 ◽  
pp. 328
Author(s):  
R.E. Campbell
Keyword(s):  
Ground Level ◽  
Tree Canopy ◽  
Dispersal Patterns ◽  
Release Point ◽  
Splash Dispersal ◽  
Data Points ◽  
Point Data ◽  
Rain Splash ◽  
Monitoring Protocols ◽  
Zero Counts

Microorganisms are incredibly difficult to trap, identify and enumerate efficiently and quickly. This makes it difficult to study incursions of new pathogens and the spread of existing ones effectively. Finding efficient ways of overcoming these difficulties is essential to guide monitoring protocols, control or mitigate spread, or find potential areas for eradication after incursions. We investigated the use of a fluorescent dye, PTSA (1,3,6,8-pyrenetetrasulfonic acid), to explore patterns of rain-splash dispersal of Neonectria ditissima spores. Spores mixed with PTSA dye were released in pear and apple trees within orchards and in an artificial setting using a marquee. Spores and dye were released from a central point source 2.5 m above ground and recaptured in a number of rain traps at ground level and within the tree canopy. It was often very difficult to detect low numbers of recaptured spores, with zero counts found at any distance from the release point. Data points were highly variable, as expected given the range of field conditions, but a clear relationship between dye and spores caught in rain traps under various scenarios was obtained. These results show the merit of PTSA tracer dye as a tool to quantify potential dispersal patterns of microorganisms in an actual landscape of interest with various rainfall scenarios.

Ramularia onobrychidis. [Descriptions of Fungi and Bacteria].

2004 ◽  
Author(s):  
J. C. David
Keyword(s):  
Great Britain ◽  
Geographical Distribution ◽  
Arachis Hypogaea ◽  
Leaf Spot ◽  
Republic Of Georgia ◽  
Leaf Fall ◽  
Splash Dispersal ◽  
Rain Splash

Abstract A description is provided for Ramularia onobrychidis. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. DISEASE: Leaf spot of sainfoin. HOSTS: Arachis hypogaea, Onobrychis altissima, O. arenaria, O. hajastana, O. hohenhackeriana, O. miniata, O. oxyodonta, O. pulchella, O. sintenisii, O. transcaucasica, O. vaginalis, O. viciifolia (BRAUN, 1998) (Fabaceae). GEOGRAPHICAL DISTRIBUTION: ASIA: Armenia, Azerbaijan (EIBATOVA, 1958), Republic of Georgia, Kabardino-Balkariya, Kazakhstan, Kirgistan, Tadzhikistan (OSIPYAN, 1975), Turkmenistan, Uzbekistan. EUROPE: Austria, Belarus (OSIPYAN, 1975), Bulgaria, Denmark, Estonia, France, Germany, Great Britain, Hungary, Italy, Latvia, Lithuania, Moldova (OSIPYAN, 1975), Romania (BONTEA, 1985), Russia, Sweden, Turkey, Ukraine, Serbia. TRANSMISSION: By wind and rain-splash dispersal of conidia. HUGHES (1949) stated that sclerotia are formed in the lesions: the leaflets are readily detached and in moist conditions the sclerotia can develop after leaf fall, they can also be blown around aiding dispersal of the fungus.

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