Efficacy of Paecilomyces lilacinus in Suppressing Rotylenchulus reniformis on Tomato

S. Alan Walters, Kenneth R. Barker

Abstract


Effects of rice-cultured Paecilomyces lilacinus on Rotylenchulus reniformis were studied in both greenhouse and field microplot tests with 'Rutgers' tomato. Numbers of R. reniformis were reduced (P = 0.05) by P. lilacinus, with suppression in the initial greenhouse test ranging from 46 to 48% for two rice + P. lilacinus treatments; the rice-only treatment caused a nonsignificant reduction of 25%. In the second greenhouse test, total R. reniformis numbers were restricted (P = 0.05) by 41% by the rice + P. lilacinus treatment, whereas the rice-only treatment had a slight negative effect (16% inhibition, NS). Total numbers of R. reniformis were suppressed 59 and 36% at midseason and harvest, respectively, in microplots infested with P. lilacinus. The fungus was recovered from egg masses via isolations in the second greenhouse test. Shoot and fruit growth of Rutgers tomato were restricted by R. reniformis in the initial greenhouse test irrespective of P. lilacinus treatment, but this nematode did not affect fresh shoot weights in the second greenhouse test, The nematode also limited shoot growth of Rutgers tomato in microplots, and P. lilacinus suppressed R. reniformis numbers sufficiently to prevent related impairment of shoot and fruit growth. This study indicated that P. lilacinus has detrimental effects on R. reniformis population development under both greenhouse and field microplot conditions. Key words: biological control, Lycopersicon esculentum, nematode, Paecilomyces lilacinus, reniform nematode, Rotylenchulus reniformis, tomato.

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