Phytophthora spp

A satisfactory control of soil densities of Phytophthora spp. and related diseases was documented in several solarization studies (Pinkas et al. 1984 Lopez-Herrera et al. 1997 McGovern et al. 2000 Benlioglu et al. 2005). Pinkerton et al. (2002)... 

Pythium spp. Phytophthora spp. sugar beets, vegetables, ornamentals avocado, soybean, citrus, apples, ornamentals... 

A novel application of the microbioassay was also developed for the discovery of compounds that inhibit Phytophthora spp. This protocol used the 96-well format for high-throughput capability and a standardized method for quantification of initial zoospore concentrations for maximum reproducibility. Zoospore suspensions were quantifiable between 0.7 and 1.5 x 105 zoospores/mL at an absorbance value of 620 nm. Subsequent growth of mycelia was monitored by measuring absorbance (620 nm) at 24-hour intervals for 96 hr. Full- and half-strength preparations of each of three media (V8 broth, Roswell Park Memorial Institute mycological broth, and mineral salts medium), and four zoospore concentrations (10, 100, 1000, and 10,000... 

Panabieres, E, Ponchet, M., Allasia, V., Cardin, L., Ricci, P. Characterization of border species among Pythiaceae several Pythium isolates produce elicitins, typical proteins from Phytophthora spp. Mycol Res 1997 101 1459-1468. 

Aliette (aluminum tris-0 ethylphosphonate) has been reported to enhance defense reactions and phytoalexin accumulation in grapes and tomatoes in response to infection by Plasmopara viticola and Phytophthora spp., respectively, and to trigger phenolic accumulation and hypersensitive cell death in tomatoes, peppers, and beans in response to infection while possessing little direct fungitoxicity (116,117). However, recent data cast doubt on the earlier reports of the low activity of Aliette as an inhibitor of Phytophthora sporulation mi vitro (118), and have attributed the protective properties of the compound to phosphorous acid which is formed in plant tissues or in certain buffer solutions of Aliette (119,120). Toxicity of phosphorous acid to Oomycetes is reversible by phosphate ion, and this may explain Aliette s lack of fungitoxicity in certain growth media. 

Smillie, R., Grant, B. and Guest, D. (1989) The mode of action of phosphite evidence for both direct and indirect modes of action on three Phytophthora spp. in plants. Phytopathology, 79, 921-926. 

Cline and Albershelm (35) suggested that the primary event in activating the biochemical processes leading to increased concentrations of phytoalexins in plants is the binding of ellcltors to receptors in the plasma membrane. Initial evidence for this was reported by Yoshlkawa et al. 36) when they found that soybean membrane preparations bound HC-laminaran (a 8-1,3-glucan elicitor from Phytophthora spp.). The receptor, while not yet characterized, appears to be a protein or glycoprotein. 

The fungicidal action of streptomycin is exerted on Oomycetes fungi (Pythium and Phytophthora spp.) which are able to absorb the antibiotic (Voros, 1965). 

When oat roots were used for bioassay, zoospores were first attracted and then caused lysis which raises the possibility that oat crops and their residues might be used to reduce soil populations of zoosporic plant pathogens. The cystospores were insensitive to concentrations of saponins or oat root extract that lysed zoospores. The zoospores lytic principle in oat root extract/exudate was believed to be a saponin, avenacin (61). The effects of avenacin (61) or root extracts on zoospores were identical to those of /0-aescin and consistent with a role of membrane active agents. Toxic effects of saponins on zoospores were also observed in Pseudoperonospora humuli Miyabe Takah. and Phytophthora spp. [139,140]. 

Like other micronutrients. Mo has been found to influence the incidence of plant diseases. Molybdenum application has been reported to decrease leaf-spot infection caused by Septoria sojina in soybeans (Girenko, 1975) and to decrease Verticillium wilt in tomatoes (Dutta and Bremner, 1981) and cotton (Gossypium spp.) (Miller and Becker, 1983). It also reduces the production of roridin E toxin by Myrothecium roridum (Fernando, Jarvis, and Bean, 1986) and zoosporangia formation by Phytophthora spp. (Halsall, 1977). Haque and Mukhopadhyay (1983) observed that soil application of Mo caused some reduction in the population of parasitic nematodes. Whether these effects are due to some specific role of Mo in plant disease resistance or are indirect effects of Mo through plant metabolism is not certain. 

Phytophthora spp. and other species of Oomycetes also have cytoplasmic 3,6-3-glucans (mycolaminarins) and their phosphate esters (73). These polysaccharides also induce wilting in avocado (Persea indica) and other plants (40) (see Table II). 

Cymoxanil is a protective and curative fungicide for foliar application it is especially active against Peronospora spp., Phytophthora spp. and Plasmopara spp. in... 

C., Inhibition of inorganic pyrophosphatase by phosphonate - A site of action in Phytophthora spp. Pestic. Biochem. Physiol. (1998) 61, 65-77. 

During the course of screening for new fungicides from microorganisms we encountered two closely related dipeptides with modest activity principally against Phytophthora spp. Herein we describe the isolation and structure elucidation of a novel fungicidal dipeptide,... 

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