| Summary: | The efficacy of four native isolations of Metarhizium anisopliae in the control of Mahanarva andigena nymphs in greenhouse and field was evaluated. In both conditions, the treatments were: four native isolations: T1: MT-51 (01), T2: P-50 (01), T3: T-63 (01) and T4: F55 (01); a commercial strain T5: Metazeb and T6 control treatment. In a greenhouse, 30 days old sugar cane seedlings were used, each one was infested with 10 fourth instar nymphs and subsequently sprinkled with 15 mL of a suspension of 1x108 conidia/mL-1 for each isolation, the commercial strain at a dose of 2x1012 conidia/ha-1 (300 g of commercial product/ha-1) and the control treatment (sterile distilled water + agral 90). In greenhouse mortality was recorded for seven days and the corrected and confirmed mortality was determined. In the field, the treatments were sprayed at the same concentrations. The effectiveness of the treatments was determined at 7 and 14 days after the application, with the Henderson-Tilton formula. In the greenhouse treatments, T1, T2 and T3 caused high percentages of confirmed mortality, with values of 71.11, 67.5 and 54.45%, respectively, higher than the commercial strain, and in the field at 14 days, the application of treatments T1 and T2, reached an efficiency of 73.08 and 69.68%, higher than other treatments. These results demonstrate that the T1 isolations: MT-51 (01) and T2: P-50 (01) in greenhouse and field induced a high mortality of M. andigena nymphs, so they are the most promising for use as control biological agents of this insect pest in the cultivation of sugar cane.
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