A variety of non-chemical alternatives to methyl bromide (MB) fumigation of soil for horticultura... more A variety of non-chemical alternatives to methyl bromide (MB) fumigation of soil for horticultural crop production have been researched in the USA. Non-chemical alternatives are highly desirable but difficult to implement to reproduce the benefits normally obtained by preplant fumigation of soil in strawberry production. Production of pathogen-free, high-quality planting materials using steam and other physical methods of soil disinfestation have not been perfected for large-scale runner plant production. Genetic resistance or tolerance to specific soilborne pathogens is important and can be improved. While crop rotation improve strawberry yields and in some cases reduced soilborne disease, the high cost of land and infrastructure for strawberry production precludes rotation as an option. Solarization, biofumigation and/or organic soil amendments have been tested but have have not been successful. Soil amendments must be used at relatively high rates for effects to be significant, a...
Fusarium oxysporum f. sp. lactucae, the causal agent of Fusarium wilt of lettuce, has been report... more Fusarium oxysporum f. sp. lactucae, the causal agent of Fusarium wilt of lettuce, has been reported in three continents in the last 10 years. Forty-seven isolates obtained from infected plants and seed in Italy, the United States, Japan, and Taiwan were evaluated for pathogenicity and vegetative compatibility. Chlorate-resistant, nitrate-nonutilizing mutants were used to determine genetic relatedness among isolates from different locations. Using the vegetative compatibility group (VCG) approach, all Italian and American isolates, type 2 Taiwanese isolates, and a Japanese race 1 were assigned to the major VCG 0300. Taiwanese isolates type 1 were assigned to VCG 0301. The hypothesis that propagules of Fusarium oxysporum f. sp. lactucae that caused epidemics on lettuce in 2001-02 in Italian fields might have spread via import and use of contaminated seeds is discussed.
It is apparent that wilt diseases continue to be a major problem in crop production because of th... more It is apparent that wilt diseases continue to be a major problem in crop production because of the number of crops affected, the number and genetic variability of pathogens involved, and their widespread occurrence throughout tropical and temperate regions under a variety of cropping systems. It is also apparent, however, that new understandings and approaches, often in combinations not previously discerned, offer exciting new prospects for research, understanding and practical control methods. The current state-of-the-art and fields for further studies were discussed by researchers actively engaged in a wide range of areas from ecological studies of physical and biological factors in the host-parasite-environmental interactions in the soil, through physiological and biochemical studies of host-parasite recognition and interaction that determine relative colonization of the host, through genetic-molecular studies of these interactions, to the most practical field studies of disease ...
Biology and Molecular Biology of Plant-Pathogen Interactions, 1986
The polyunsaturated fatty acids, arachidonic (AA) and eicosapentaenoic (EPA), both constituents o... more The polyunsaturated fatty acids, arachidonic (AA) and eicosapentaenoic (EPA), both constituents of Phytophthora infestans, reproduce the hyper-sensitive response when applied to the surface of potato tuber slices [1]. Their effect involves rapid, but localized cell death, browning of the tissue, leakage of electrolytes and foremost, marked inhibition of steroid glycoalkaloid (SGA) accumulation with parallel elicitation of sesquiterpenoid stress metabolites (SSM) accumulation [1,2]. This study refers to the effect of chemicals which inhibit steroid synthesis in fungi and plants such as sterol-inhibiting fungicides [3,4,5] on potato tuber slices. Research concentrated on their effects on SGA and SSM accumulation. The assumption that AA and EPA have a hormonal effect by inhibiting or promoting biochemical processes like phytohormones, justified experimental work on the effect of the main phytohormones indole-3- acetic acid, gibberellic acid and abscisic acid on potato tuber slices. The latter has been reported to affect SSM accumulation in applications with AA [6]. Our aim was to elucidate the mode of action of AA as an elicitor of SSM.
A variety of non-chemical alternatives to methyl bromide (MB) fumigation of soil for horticultura... more A variety of non-chemical alternatives to methyl bromide (MB) fumigation of soil for horticultural crop production have been researched in the USA. Non-chemical alternatives are highly desirable but difficult to implement to reproduce the benefits normally obtained by preplant fumigation of soil in strawberry production. Production of pathogen-free, high-quality planting materials using steam and other physical methods of soil disinfestation have not been perfected for large-scale runner plant production. Genetic resistance or tolerance to specific soilborne pathogens is important and can be improved. While crop rotation improve strawberry yields and in some cases reduced soilborne disease, the high cost of land and infrastructure for strawberry production precludes rotation as an option. Solarization, biofumigation and/or organic soil amendments have been tested but have have not been successful. Soil amendments must be used at relatively high rates for effects to be significant, a...
Fusarium oxysporum f. sp. lactucae, the causal agent of Fusarium wilt of lettuce, has been report... more Fusarium oxysporum f. sp. lactucae, the causal agent of Fusarium wilt of lettuce, has been reported in three continents in the last 10 years. Forty-seven isolates obtained from infected plants and seed in Italy, the United States, Japan, and Taiwan were evaluated for pathogenicity and vegetative compatibility. Chlorate-resistant, nitrate-nonutilizing mutants were used to determine genetic relatedness among isolates from different locations. Using the vegetative compatibility group (VCG) approach, all Italian and American isolates, type 2 Taiwanese isolates, and a Japanese race 1 were assigned to the major VCG 0300. Taiwanese isolates type 1 were assigned to VCG 0301. The hypothesis that propagules of Fusarium oxysporum f. sp. lactucae that caused epidemics on lettuce in 2001-02 in Italian fields might have spread via import and use of contaminated seeds is discussed.
It is apparent that wilt diseases continue to be a major problem in crop production because of th... more It is apparent that wilt diseases continue to be a major problem in crop production because of the number of crops affected, the number and genetic variability of pathogens involved, and their widespread occurrence throughout tropical and temperate regions under a variety of cropping systems. It is also apparent, however, that new understandings and approaches, often in combinations not previously discerned, offer exciting new prospects for research, understanding and practical control methods. The current state-of-the-art and fields for further studies were discussed by researchers actively engaged in a wide range of areas from ecological studies of physical and biological factors in the host-parasite-environmental interactions in the soil, through physiological and biochemical studies of host-parasite recognition and interaction that determine relative colonization of the host, through genetic-molecular studies of these interactions, to the most practical field studies of disease ...
Biology and Molecular Biology of Plant-Pathogen Interactions, 1986
The polyunsaturated fatty acids, arachidonic (AA) and eicosapentaenoic (EPA), both constituents o... more The polyunsaturated fatty acids, arachidonic (AA) and eicosapentaenoic (EPA), both constituents of Phytophthora infestans, reproduce the hyper-sensitive response when applied to the surface of potato tuber slices [1]. Their effect involves rapid, but localized cell death, browning of the tissue, leakage of electrolytes and foremost, marked inhibition of steroid glycoalkaloid (SGA) accumulation with parallel elicitation of sesquiterpenoid stress metabolites (SSM) accumulation [1,2]. This study refers to the effect of chemicals which inhibit steroid synthesis in fungi and plants such as sterol-inhibiting fungicides [3,4,5] on potato tuber slices. Research concentrated on their effects on SGA and SSM accumulation. The assumption that AA and EPA have a hormonal effect by inhibiting or promoting biochemical processes like phytohormones, justified experimental work on the effect of the main phytohormones indole-3- acetic acid, gibberellic acid and abscisic acid on potato tuber slices. The latter has been reported to affect SSM accumulation in applications with AA [6]. Our aim was to elucidate the mode of action of AA as an elicitor of SSM.
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