SUPPRESSION OF MELOIDOGYNE-ARENARIA RACE-1 BY SOIL APPLICATION OF ENDOSPORES OF PASTEURIA-PENETRANS

The potential of Pasteuria penetrans for suppressing Meloidogyne arena ria race 1 on peanut (Arachis hypogaea) was tested over a 2-year perio d in a field microplot experiment. Endospores of P. penetrans were mas s-produced on M. arenaria race 1 infecting tomato plants. Endospores w ere inoculated in the first year only at rates of 0, 1,000, 3,000, 10, 000, and 100,000 endospores/g of soil, respectively, into the top 20 c m of microplots that were previously infested with M. arenaria race 1. One peanut seedling was planted in each microplot. In the first year, root gall indices and pod galls per microplot were significantly redu ced by 60% and 95% for 100,000 endospores/g of soil, and 20% and 65% f or 10,000 endospores/g of soil, respectively. Final densities of secon d-stage juveniles (J2) in soil were not significantly different among the treatments. The number of endospores attached to J2 and percentage of J2 with attached endospores significantly increased with increasin g endospore inoculation levels. Pasteuria penetrans significantly redu ced the densities of J2 that overwintered. In the second year, root an d pod gall indices, respectively, were significantly reduced by 81% an d 90% for 100,000 endospores/g of soil, and by 61% and 82% of 10,000 e ndospores/g of soil. Pod yields were significantly increased by 94% fo r 100,000 and by 57% for 10,000 endospores/g of soil, respectively. Th e effect of P. penetrans on final densities of J2 in soil was not sign ificant. Regression analyses verified the role of P. penetrans in the suppression of M. arenaria. The minimum number of endospores required for significantly suppressing M. arenaria race 1 on peanut was 10,000 endospores/g of soil.