The increasing of problems like resistance, impacts on non-target organisms, environmental damages, associated with the use of chemicals pesticides, are speeding up the need for the development of safer, alternative crop protectants and pest control such as protease inhibitors. They form large, highly diversified and multigenic families that have probably co-evolved with the main pest families and they are an important component in the multimechanistic defensive strategy employed by many plant species. In this work, we describe the effect of a trypsin inhibitor from I. laurina (ILIT) seeds on larval development of D. saccharalis. The physiological effects of this protein was monitored by feeding the neonate larvae in artificial diet in several concentration (0.1-0.2 and 0.4 w/v) and then determining the number and mass of surviving larvae, the consumption and utilization of food and feces eliminated for analysis of nutritional indices. The results revealed that ILIT affects significantly the larval viability of D. saccharalis causing 100% of mortality in the two larger concentrations. The treatment 0.1% altered the physiology and metabolism of the insect, reducing of about 3 and 4 times the efficiency of conversion of ingested food and the efficiency of conversion of digested food, respectively, increasing the metabolic cost of these larvae causing a decrease of 56% in the weight and 11.4% of mortality when compared whit the control group, only treated whit the artificial diet without the inhibitor. Therefore, it can be verified that ILIT contains an expressive insecticide properties for the  D. saccharalis larvae, being able to be used as an important tool in the genetic engineering of plants.

Word Keys: Protease Inhibitor, Diatraea saccharalis, Pest Control, Nutritional Indices.

Support: Capes, CNPq, FUNDECT and FINEP