Potencial inseticida de extratos de funcho, erva-doce, cravo-da-índia e do preparado homeopático para o controle de pulgão em couve

Abstract

The use of natural substances for pest management in agriculture is, economically, a viable option and has benefits for both human-beings and environment, due to its low persistence and toxicity. Thus, this trial aimed at determining the insecticidal potential of extracts and essential oils of fennel (Foeniculum vulgare), sweet herb (Pimpinella anisum), clove (Caryophillus aromaticus) and of homeopathic preparations from CH 05 and CH 06 aphid on the control of Brevicoryne brassicae in cabbage (Brassica oleracea var. acephala). The treatments were: fennel extracts, sweet herb and cloves at 10%; fennel oils, sweet herb and cloves at 1%; homeopathic preparations with CH 05 and CH 06 aphid; control with distilled water. The mortality tests were done concerning nymphs and adults of aphids in laboratory, with three replications, each one consisting of a cabbage leaf kept inside a Petri dish containing moistened cotton. On each plate, ten nymphs were released added with a 1 mL spray of the respective solutions. The plates were covered with a perforated plastic film and incubated with a 12 hour photoperiod at 25 ° C. Evaluations were performed after 1, 12, 24, 48 and 72 hours. After analysis in the laboratory, some tests were done with the culture, in pots, only with the Indian cloves extracts at 10% and fennel oil at 1% treatments, since they were significant. There was, moreover, the sensorial analysis of cabbage, treated with clove extract at 10% and fennel oil at 1%. Data analysis was performed by analysis of variance and averages comparison by Tukey, at 5% of significance. In lab tests, it was found out that fennel oil at 1% showed the best rate of mortality on aphid nymphs, which means 70%, at 72 h, followed by clove extract at 10% with 37% of mortality. It was registered for survival of adults aphids that the fennel oil at 1%, fennel extract at 10% and clove extract at 10% had the lowest survival rates, as: 46%, 53% and 53 %, respectively. A mortality test was carried out in the culture and it was registered the effectiveness of clove extract at 10% and fennel oil at 1%, and they had 6% and 8% of survival in adults aphids, respectively. The sensorial analysis of cabbage did not indicate any significant difference among them, at 5% significance.