Alternaria spp

Saprophytic, dark pigmented fungi such as Alternaria spp. can infect a wide range of plant species, especially tissues that are exposed to other biotic or abiotic stressors and older and senescing plant tissues. Also, wet weather conditions favour attack by Alternaria spp. Inoculum of Alternaria and potentially production of altemariol is further enhanced when cereal straw and stubble is left on the soil surface and not sufficiently incorporated into the soil after harvest (direct seeding and minimum tillage systems). 

Seed treatment for control of Rizoctonia solani, Fusarium spp., Alternaria spp., Aspergillus spp., etc. in cotton, legumes of other crops... 

Zinniol. Zinniol [13] was first described as a phytotoxic metabolite of Alternarla zinniae (21). Zinniol is now known to be produced by many Alternaria spp., including fungal pathogens of weeds and crop plants (21). This compound causes necrosis in plants (21)> S2) and "green island formation, as discussed earlier. 

Pathogens that are difficult to mass-produce offer a technological challenge. Many fungi such as Alternaria spp. and some Colle-totrichum spp. do not sporulate under liquid fermentation, the preferred method of commercial inoculum production. Labor-intensive... 

Tenuazonic acid Alternaria spp. Infected cotton plants... 

Clear, R.M. T.W. Nowicki J.K. Daun. Soybean seed discoloration by Alternaria spp. and Fusarium spp., eflFects on quality and production of fusariotoxins. Canadian J. Plant Pathol. 1989,... 

Tenuazonic acid (741), a phytotoxin produced by Alternaria spp., is structurally related to the tetramic acid family of compounds, and has been found to exhibit antibiotic activity (511). Since 1964, there have been several publications on the total synthesis of 741 (512-515), including the report by Poncet and his group in 1990 (516) (Scheme 11.10). A general method to synthesize the tetramic acids is an intramolecular Dieckmann cyclization of (V-acyl amino esters. Beginning with methyl L-isoleucinate 780, the A/-acyl compound 782 was obtained through a nucleophilic reaction (512), which then cyclized to tenuazonic acid 741 under basic conditions and neutralization by acidic work-up. The synthetic product showed a diastereomeric excess of 89%, with the major epimer presenting the same configuration as its precursor (517). 

Linseed and flax are susceptible to some important seed borne diseases. No more than 5% of seeds should be infected with the following Botrytis spp., Alternaria spp., Fusarium spp., Colletotrichum Uni and Ascochyta linicola. (In the case of flax seed even more stringent conditions apply and no more than 1% of seed should be contaminated with. linicola.) Seed crops are normally sprayed with an approved fungicide before the end of flowering in order to try to achieve these standards. 

Black Aspergillus niger, alternaria spp., cladosporium herbarum, gliomastix mucorum... 

Black Aspergillus niger, ubiquitous in black colonies Black Alternaria spp., grows in black or gray colonies Black Cladosporium herbarum, found on dead herbaceous and woody plants, textiles, rubber, etc. 

Wood pulp workers disease Contaminated wood pulp Alternaria spp... 

The other major genera that were isolated on a less frequent basis in the survey included many of the same field fungi that have been isolated from commercial tobacco samples such as Alternaria spp.> Rhizopus nigricans Fusarium spp., Cladosporium> Chaetomium> Trichoderma viride> Phoma spp., and Mucor spp. (Table A). These field fungi invade the substrate prior to harvest and require an abundance of moisture (at least 24% to 25%) on the substrate in order to support their growth (Christensen and Kaufman, 1965). 

The genus Alternaria is widely distributed in nature, and a number of Alternaria spp are pathogenic to plants (66). A. alternata f sp. lycopersici was isolated from susceptible asc/asc) tomatoes with stem canker disease (33,40, 48). The active phytotoxin responsible... 

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