Combate biológico de la mustia hilachosa (Thanatephorus cucumeris) en el frijol en Panamá

Abstract

The objectiveof this work was to evaluate the capacity of Trichodermasp., Metarrhizium anisopliae and endophytic bacteria ofT. cucumeris (Frank) Donk under fi eld conditions, for thebiological control of web blight (T. cucumeris) in beans.Applications of Bacillus subtilis, Trichoderma sp. (Strain2-Villa Margarita), Trichoderma sp. (Strain 1-Colombia) andM. anisopliae (Colombia) at concentration of 2 x 107 conidia/ml of water), B. subtilis at rates of 0.335, 0.670, 1.005 and1.340 g ai / ml of water + 36 g ai Chlorothalonil /ha, benomyl50 WP with doses of 250 g ai / ha and a control treatment wereconducted. Results revealed high differences (P ≤ 0.0003)between treatments; the treatment with lower severity was M.anisopliae, followed by B. subtilis with 1,340 g ai /ml of water+ Chlorothalonil at 36 g ai/ha with 11.87% and B. subtilisto 0,335 g ai /l of water + Chlorothalonil at 36 g ai/ha, with15.0%. The treatments affected to the greatest degree were B.subtilis with 0,670 g ai/l of water + Chlorothalonil with 36g ai/ha, Trichoderma sp. (Strain 2-Villa Margarita) and thecontrol treatment with 26.2%, 22.25% and 21.85% of severity,respectively. The regression equation for the experiment Y =2502.91-13.021* Sev, was signifi cant and indicated lossesof 13.02 kg for each percent increase of the disease. Themarginal analysis revealed that the treatment with highest gainwas M. anisopliae, recording a net profi t of 28.34%.