High soil moisture reduces common scab caused byStreptomyces turgidiscabiesandStreptomyces europaeiscabieiin potato

Author(s):  
Tor J. Johansen ◽  
Merete W. Dees ◽  
Arne Hermansen
1951 ◽  
Vol 4 (3) ◽  
pp. 211
Author(s):  
GC Wade

The disease known as white root rot affects raspberries, and to a less extent loganberries, in Victoria. The causal organism is a white, sterile fungus that has not been identified. The disease is favoured by dry soil conditions and high soil temperatures. It spreads externally to the host by means of undifferentiated rhizomorphs; and requires a food base for the establishment of infection. The spread of rhizomorphs through the soil is hindered by high soil moisture content and consequent poor aeration of the soil.


Weed Science ◽  
1985 ◽  
Vol 33 (3) ◽  
pp. 395-399 ◽  
Author(s):  
John D. Nalewaja ◽  
Zenon Woznica

Glasshouse and growth chamber experiments were conducted to determine chlorsulfuron {2-chloro-N-[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino] carbonyl] benzenesulfonamide} phytotoxicity to kochia [Kochia scoparia(L.) Schrad. ♯ KCHSC] and green foxtail [Setaria viridis(L.) Beauv. ♯ SETVI] as influenced by temperature and humidity for 1 week after treatment, and by soil moisture and nitrogen. Chlorsulfuron was more phytotoxic to both kochia and green foxtail at 95 to 100% than at 45 to 50% relative humidity for 1 week after treatment whether at 10, 20, or 30 C. Chlorsulfuron phytotoxicity was similar with all posttreatment temperatures at each humidity, except that phytotoxicity was lower at 30 C than at 10 or 20 C at 90 to 100% humidity. Surfactant added to chlorsulfuron exhanced control of kochia more than that of green foxtail and overcame temperature and humidity effects on chlorsulfuron phytotoxicity. A simulated rainfall of 2 mm after chlorsulfuron application reduced toxicity of chlorsulfuron to green foxtail more than to kochia. Chlorsulfuron was more phytotoxic to green foxtail growing with a high than a low soil nitrogen level. High soil moisture following chlorsulfuron application enhanced phytotoxicity to kochia and green foxtail compared to high soil moisture before treatment.


1964 ◽  
Vol 44 (2) ◽  
pp. 157-160
Author(s):  
R. B. MacLaren ◽  
J. D. E. Sterling

High soil moisture and high relative humidity gave a higher incidence of brittle awns on barley than did restricted soil moisture and low relative humidity. Ash content of awns was highest when soil moisture and relative humidity were maintained at high levels. Helminthosporium sativum (P, K and B) infection reduced awn brittleness of one variety and had no effect on the others.No differences in cell structure of the awns were attributed to treatment.


1965 ◽  
Vol 11 (3) ◽  
pp. 483-489 ◽  
Author(s):  
E. A. Peterson ◽  
J. W. Rouatt ◽  
H. Katznelson

The influence of soil moisture on the microbial population of rhizosphere soil and of the root surface (rhizoplane) of wheat was studied under controlled conditions. Fertile soil adjusted to 30%, 60%, and 90% of its moisture-holding capacity was used. Bacterial counts and numbers of specific "physiological groups" of bacteria all increased in the rhizosphere and the rhizoplane as soil moisture decreased. Taxonomic studies of the bacteria isolated from the rhizoplane showed a marked preponderance of species of Pseudomonas under conditions of low and intermediate soil moisture content. On the other hand species of Arthrobacter, Bacillus, and Cytophaga dominated the population at high soil moisture. Although the distribution of fungi on the roots was very similar for the low and intermediate moisture levels, there was some restriction of colonization at the high level. Species of Mortierella, Rhizopus, Chaetomium, Curvularia, and Helminthosporium were not represented among isolates from roots at high soil moisture and the relative incidence of species of Fusarium and Phoma decreased. However, high soil moisture favored root colonization by species of Rhizoctonia and sterile dark fungi.


Author(s):  
Tracy Rowlandson ◽  
Sarah Impera ◽  
Jonathon Belanger ◽  
Aaron A. Berg ◽  
Brenda Toth ◽  
...  

2006 ◽  
Vol 54 (1) ◽  
pp. 11 ◽  
Author(s):  
Peter J. Prentis ◽  
Noel M. Meyers ◽  
Peter B. Mather

Post-germination buoyancy has been proposed to reduce seedling establishment in amphibious plants if seeds germinate under flooded conditions. We tested this hypothesis in two amphibious species, Helmholtzia glaberrima (Hook.) and Philydrum lanuginosum (Banks & Sol.). We tested whether seed germination was affected by different levels of inundation, whether seedlings germinating underwater floated and whether seedlings established after prolonged floatation at rates comparable to seedling establishment in waterlogged soil. Germination underwater and in waterlogged soil was similar for both species. Seeds germinating underwater exhibited post-germination buoyancy and established at similar rates to seedlings in waterlogged soil. The results demonstrated that if seeds germinated underwater, post-germination buoyancy conferred the potential to avoid inundation and promote establishment, when waters recede and/or in areas of high soil moisture that are not submerged. More generally, this finding showed that post-germination buoyancy can promote seedling dispersal and the deposition of seedlings in conditions more favourable for establishment if seeds germinate under flooded conditions or in permanent wetlands.


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