Nutrição mineral de cana-de-açúcar e uso de Metarhizium anisopliae (METSCH) Sorok no manejo de Diatraea saccharalis (FABR., 1974) (Lepidoptera : crambidae)

Abstract

In the culture of sugarcane (Saccharum spp.), the damage caused by the fall armyworm Diatraea saccharalis (Fabricius, 1794) (Lepidoptera: Crambidae) is significant because the penetration of microorganisms in holes made by the caterpillars, causing reduction in the production of sugar and alcohol. Among the tactics of integrated pest management (IPM) is the mineral nutrition, induction of resistance, being the silicon an option that can be used in the management, in addition to the use of fungi entomopatogênicos as an alternative to increment the management of species of Diatraea spp. In this way the present work aimed to analyze the influence of different doses of nitrogen, phosphorus, potassium, the effect of soil fertilization with silicon applied in the culture of sugar cane, on intensity of infestation of D. saccharalis and its crop damage mentioned, in addition to assessing the effect of isolate IBCB 425 Meterhizium anisopliae fungus (Ilyich Metchnikoff) Sorokin (Hypocreales: Clavicipitaceae) on eggs, larvae and pupae of D. saccharalis, under laboratory conditions. For this reason it was used the variety RB92579 planted in pots in the Vegetation House, with three experiments, in the first was evaluated different doses of fertilizer, with doses of nitrogen, phosphorus and potassium. In the second was applied silicon in the form of calcium and magnesium silicate, at a dosage of 1, 2, 3, 4 e 5 g/dm³ and checked the damage caused by caterpillars of D. saccharalis in the culture of sugar cane. Already in the third, caterpillars of D. saccharalis were sprayed with 0,5 x 107; 1 x 107; 1,5 x 107 e 2,0 x 107 and 2.0 x 107 conidia g-1 M. anisopliae and examined the effect of the fungus on eggs and caterpillars of the drill. In general, for the experiment with NPK, the nitrogen fertilization increases the intensity of damage caused by the attack of D. saccharalis in the culture of sugar cane, not showing significant interference on the productivity of stalks. Already with relation fertilisation phosphate and potassium fertilization, these have promoted productivity gain without which the intensity of damage was affected. With respect to the application of silicon in conditions of the Vegetation House was verified the contribution to the reduction of the ID%, however without significantly influence the productivity. Already the fungus M. anisopliae presented pathogenic activity the D. saccharalis in concentrations of 1.0 x 107, 1.5 x 107 and 2.0 x 107 conidia g-1, which reveals that this fungus have the potential to be used in the Integrated Management of D. saccharalis.