Insecticidal effects of croton urucurana extracts and crude resin on dysdercus maurus (Hemiptera: Pyrrocoridae)

Abstract

Yield loss in different crops due to the attack of various classes of insect pests is a worldwide problem. Sucking type Dysdercus maurus causes damage to many crop species. Diverse plant species have been studied in order to identify the active ingredients responsible for their insecticidal activity against pests of economic importance. To verify the insecticidal activity of the stem bark and crude resin of Croton urucurana Baillon 1864 (Euphorbiaceae) against Dysdercus maurus Distant 1901 (Hemiptera: Pyrrhocoridae), the methanolic (EMeOH) extract, dichloromethane fraction (FDM), ethyl acetate fraction (FAE) and crude resin were applied topically with micro- applicator on the dorsal side of the mesothoracic region of third instar nymphs and the ventral side of adult insects and incorporated into an artificial diet. The average adult mortality of Dysdercus maurus treated topically with 0.5, 1.0 and 2.0% of the extracts mentioned above was significantly higher compared to controls. The FAE showed high insecticidal potential, having a higher mortality rate, extending the duration of the larval stages and resulting in malformed adults. Third instar nymphs fed with artificial seeds containing 1% FAE died three days after the start of the experiment, even before the molt to the next instar. For all treatments the death rate was greater for immature forms. These findings may provide a useful beginning for the development of biopesticides. Further studies will be carried out on mating, fecundity and proteolytic activity. © 2012 Academic Journals Inc.