BIOTIC, EDAPHIC, AND CULTURAL-FACTORS ASSOCIATED WITH STRAWBERRY BLACK ROOT-ROT IN NEW-YORK

Blackening and decay of roots in association with plant stunting are c ommon in perennial strawberry (Fragaria xananassa Duch.) plantings wor ldwide; this syndrome is commonly referred to as black root rot (ERR), although its causal agent(s) are not well characterized. We conducted a New York field survey that measured many physical and cultural fact ors in healthy and diseased fields to identify those most strongly ass ociated with ERR. Factors significantly correlated with ERR symptoms w ere soil compaction, fine soil texture, absence of raised beds, high a pplication rates of the herbicide terbacil, advanced age of planting, nonuse of the fungicide metalaxyl, and cumulative years of strawberry monoculture. Populations of Pratylenchus spp. were not associated with poor root health. The data suggest that most factors that compromise root growth may predispose strawberry plants to infection by site-spec ific BRR pathogens. Chemical names used: 3-tert-butyl-5-chloro-6-methy luracil (terbacil); N-(2,6-dimethylphenyl)-N-(methoxyacetyl) alanine m ethyl ester (metalaxyl).