Preliminary investigations on suppression of Meloidogyne incognita (Kofoid & White) Chitwood (Nematoda: Heteroderidae) by antagonistic rhizobacteria

Abstract

Summary Fluorescent Pseudomonad strains have been obtained from diseased second juveniles from Meloidogyne incognita (Kofoid & White, 1919) Chitwood, 1949 (Nematoda: Heteroderidae) infected tomato roots. After the screening in vivo made by 5 different isolated strains, Strain Pat1 has been selected to test the antagonistic effects on the root-knot nematodes. Strain Pat1 has been identified as non plant pathogenic Pseudomonas fluorescens Migula, 1895 (Proteobacteria: Pseudomonadaceae) according to the test result. Cucumber (Cucumis sativus) cv Sardes has been used as test plant. Bacterial suspension (10 9 cfu/ml) was applied by three different ways: 1) Seed bacterization; 2) Seed bacterization plus seedling drenching; and 3) Seedling drenching. The eggs of rootknot nematodes have been obtained from diseased tomato roots by blender-sieve method for infection cucumber seedlings with root-knot nematodes. 20 000 eggs/plant have been given to cucumber seedlings during transplanting. The plants have been observed for symptom development for 10-11 weeks in climatized room under controlled conditions. Symptom development has been evaluated by using 0-4 scale for upper parts of plants, and 0-10 Zeck’s root-knot scale for the roots. When seed bacterization and seed bacterization plus seedling drenching applicat ions compared with positive control; plants infected with root-knot nematodes alone, it was determined that disease symptoms on upper parts of the plants were reduced 35 % and 21 %; gal formation on the roots were reduced 44 % and 39 %, * This study was presented at the VIII th European Congress of Entomology held on 17-22 September 2006 in Izmir (TURKEY) and published as an abstract.