Application of Burkholderia Cepacia and Trichoderma Virens , Alone and in Combinations, against Meloidogyne Incognita on Bell Pepper

Meyer, S. L. F, D. P. Roberts, D. J. Chitwood, L. K. Carta, R. D. Lumsden, and W. Mao. 2001. Application of Burkholderia cepacia and Trichoderma virens , alone and in combinations, against Meloidogyne incognita on bell pepper. Nematropica 31:75-86. Bell pepper ( Capsicum annuum L.) seeds and seedlings were treated with three potentially beneficial microbes, applied alone and in combinations, to compare effects of these formulations on rootknot nematode ( Meloidogyne incognita ) populations and on plant growth in the greenhouse. Individual treatments (applied as seed coatings and seedling drenches) were formulations of Burkholderia cepacia strains Bc-2 and Bc-F, and of Trichoderma virens strain Gl-3. Combination treatments were BcF+Gl-3, Bc-2+Gl-3, Bc-F+Bc-2, and Bc-F+Bc-2+Gl-3. At transplanting, pepper seedlings were each inoculated with 10 000 M . incognita eggs or left uninoculated, and harvested 10 weeks later. Nonviable microbe formulations of each individual strain were also applied; these were tested only on nematodeinoculated plants. No treatment consistently affected plant growth. Numbers of eggs + second-stage juveniles (J2) per g root were significantly lower with the Bc-2, Bc-F, and Gl-3 treatments than in the untreated controls, and highest with the nonviable Gl-3 treatment. This indicates that the viable preparations suppressed M . incognita numbers on pepper under the greenhouse test conditions. Importantly, the egg + J2 numbers recorded from combination treatments were not significantly different from untreated controls, suggesting that strain combinations decreased biocontrol effectiveness relative to applications of individual microbes.