Evaluation of Bacillus Firmus (Votivo®) and Paecilomyces Lilacinus Strain 251 (NemOut®) for the Biocontrol of Reniform Nematode Rotylenchulus Reniformis

Commercial formulations of Bacillus firmus and Paecilomyces lilacinus strain 251 were evaluated separately on cotton plants grown in silty clay loam autoclaved field soil under greenhouse conditions. In the first trial, B. firmus was evaluated as a seed treatment in three different rates. The seed treatments were: 1) Untreated seed, 2) Imidacloprid  (500 g ai/100kg),  3) B. firmus (0.0071 mg Al/seed),  4) B. firmus (0.071 mg Al/seed), and 5) B. firmus (0.71 mg Al/seed). In the second trial, P. lilacinus was evaluated as a wettable powder formulation. Treatments were: 1) Control without nematodes, 2) Control with nematodes, 3) P. lilacinus (0.1 gr/100 ml), 4) P. lilacinus (0.5 gr/100 ml), and 5) P. lilacinus (1 gr/100 ml). Data was recorded every five days until day thirty. Variables measured were plant height, shot and root weight, females and eggs per gram of root, and vermiforms in 480 grams of soil. Results for B. firmus trial show that there were no differences in plant height (P≤0.49), and shot (P≤0.77) and root weight (P≤0.62). However, number of vermiforms (P≤0.01), females (P≤0.001) and eggs per gram (P≤0.01) of root were lower in treatment 5 compared to the rest of the treatments 30 DAP. For the P. lilacinus trial, for plant variables there were no statistical differences among the treatments were R. reniformis was present (P≤0.88). In nematode variables, treatment 5 shows a consistent reduction in females and eggs per gram of root from 15 to 30 DAP (P≤0.01), contrary to vermiform reduction that is only lower 30 DAP (P≤0.01). Results show promising potential of these two biocontrol agents against R. renifomis. Further studies will evaluate them separated and mixed together in non-autoclaved field soil.