Resistência genética do tomateiro e potencial de extratos de plantas espontâneas no controle alternativo de Neoleucinodes elegantalis (Guenée, 1854) (Lepidoptera: Crambidae)

Abstract

Neoleucinodes elegantalis (Guenée, 1854) (Lepidoptera: Crambidae), a pest of tomato production in Brazil is basically controlled with chemicals insecticides. This work was carried out with the overall objective of producing information on alternative forms to control N. elegantalis, involving genetic resistance of tomato (Chapter I) and botanical extracts from weeds (Chapter II), as well as evaluating the selectivity of these botanical extracts on adults of a predator, Coleomegilla maculata (Chapter III). In Chapter I, the objective was to evaluate eight tomato varieties (Viradoro, Nemadoro, Tospodoro, HEI36, LAI148, LAI144, LAI132 and UC82) in the field under organic management, and in laboratory conditions, to identify non- preference (antixenosis) oviposition of N. elegantalis. The assay at the field was conducted at Seropédica, RJ, Brazil, in randomized complete block design, with eight varieties, three replications and two sampling times. The laboratory assay was conducted in a cage, in a randomized complete blocks design, with eight varieties as treatments and eight replicates (days). It was noted that N. elegantalis, at the Field, had lower preference for oviposition in the fruit variety HEI36, unlike the variety LAI148, which in laboratory conditions showed a tendency to present fewer eggs and hatched larvae. In Chapter II, the objective was to evaluate the effect of deterrence of alcoholic extracts of species of weeds Cyperus rotundus, Commelina benghalensis, Richardia brasiliensis and Euphorbia heterophylla on oviposition of N. elegantalis, at different concentrations. The assay was conducted in a laboratory with an randomized complete blocks design, whose treatments were extracts of four species at concentrations 5%, 10% and 15% (4X3 factorial) with two additional treatments: control 0% (alcohol diluted in distilled water to 15%) and absolute control (distilled water), with 8 replicates (days). Green fruits of tomato cultivar Marmande (susceptible) were sprayed with the extracts and placed in a cage containing 150 pairs of N. elegantalis. Four cages were used for concentration of all extracts. The alcoholic extract of Euphorbia heterophylla at different concentrations (5%, 10% and 15%), presented effect of deterrence on oviposition of N. elegantalis differing from the other extracts. In chapter III aimed to evaluate the selectivity of alcoholic extracts of weeds Cyperus rotundus, Commelina benghalensis, Richardia brasiliensis, Euphorbia heterophylla, in three different concentrations applied to 10 adult individuals of C. maculate, by replication. The effects of extracts on insect biological parameters were evaluated along 30 days after spraying. The trial was conducted in laboratory with a complete randomized design. Treatments was alcoholic extracts of four plant species diluted in distilled water at three concentrations (5, 10 and 15%) (4x3 factorial) with two controls, 15% alcohol and distilled water. In general, the extracts showed selectivity for the adult C. maculata treated topically, although Euphorbia heterophylla has affected the number of hatched larvae and reduced egg viability when compared with other treatments.