Pathogenicity and reproduction of P̲ṟa̲ṯy̲ḻe̲ṉc̲ẖu̲s̲ a̲ḻḻe̲ṉi̲ and P̲.̲ Ḇṟa̲c̲ẖy̲u̲ṟu̲s̲ on selected soybean cultivars

The lesion nematode, Pratylenchus alleni, a potential pest of soybean, was found in soil samples from four of nine west Tennessee counties. Twelve soybean cultivars ('Bedford', 'Bragg', 'Centennial', 'Coker 136', 'Dare', 'Essex', 'FFR 666', 'Forrest', 'Lee 74', 'McNair 500', 'Pickett 71', and 'York'), recommended for cultivation in Tennessee were tested for reproductive suitability to P. alleni and P. brachyurus in the greenhouse. For these suitability studies, 1000 larvae and adults were pipetted onto or around each seed or seedling in clay pots. Ten weeks after inoculation, roots were harvested, blotted dry, and weighed. Nematodes were extracted from the roots in a mist chamber for two weeks. Numbers of P. alleni per gram of fresh root of 'Pickett 71' were significantly greater than most other cultivars, and 'Lee 74' was more suitable than 'Coker 136', 'Dare', 'Essex', or 'McNair 500', but this difference was not obtained in subsequent experiments. All soybean cultivars tested were suitable for reproduction of P. alleni. The ratio of males and of adults to the total recovered population were not significantly different among the cultivars. No significant differences in reproduction of P. brachyurus among the cultivars were noted. In a host range test, numbers of P. alleni increased significantly on snapbean, tomato, wheat, soybean, cowpea, corn, and potato, but declined on tobacco, lima bean, alfalfa, cabbage, cotton, watermelon, and peanut. The potential of lesion nematodes for reproduction on certain crops in rotation with soybeans should be taken into account when designing pest management strategies for soybean.