Insecticidal Potential of Fennel, Sweet Herb, Clove Extracts and Homeopathic Preparations to Control Aphid in Cabbage

Abstract

O uso de substÃncias naturais para manejo de pragas da agricultura à uma opÃÃo economicamente viÃvel e traz benefÃcios tanto ao homem como ao ambiente, devido a sua baixa persistÃncia e toxicidade. Dessa forma, o objetivo do trabalho em questÃo foi verificar o potencial inseticida de extratos e Ãleos essenciais de funcho (Foeniculum vulgare), erva doce (Pimpinella anisum), cravo-da-Ãndia (Caryophillus aromaticus) e dos preparados homeopÃticos para o controle de Brevicoryne brassicae em couve (Brassica oleracea var. acephala). Os tratamentos utilizados foram os extratos de funcho, erva-doce e cravo-da-Ãndia a 10%; Ãleos de funcho, erva-doce e cravo-daÃndia a 1%; preparados homeopÃticos de pulgÃo CH 05 e CH 06 e controle com Ãgua destilada. Realizaram-se testes de mortalidade sobre ninfas e adultos de pulgÃo em condiÃÃes de laboratÃrio, com trÃs repetiÃÃes, cada uma constituÃda por uma folha de couve mantida no interior de uma placa de Petri contendo algodÃo umedecido. Em cada placa, foram liberadas dez ninfas e pulverizado 1 mL das respectivas caldas. As placas foram cobertas com filme plÃstico perfurado e incubadas com fotoperÃodo de 12 horas a 25 ÂC. AvaliaÃÃes foram realizadas apÃs 1, 12, 24, 48 e 72 h. ApÃs anÃlise em condiÃÃes de laboratÃrio, realizaram-se testes na cultura, em vasos, somente com os tratamentos extrato de cravo-da-Ãndia a 10% e Ãleo de funcho a 1%, pois os mesmos apresentaram-se significativos. Realizou-se, ainda, anÃlise sensorial das couves tratadas com o extrato de cravo a 10% e Ãleo de funcho a 1%. A anÃlise dos dados ocorreu por anÃlise de variÃncia e comparaÃÃo de mÃdias por Tukey, a 5% de significÃncia. Nos testes realizados em laboratÃrio, verificou-se que, o Ãleo de funcho a 1% apresentou a melhor mortalidade sobre as ninfas de pulgÃo, ou seja, 70%, Ãs 72 h, seguido do extrato de cravo a 10%, com 37% de mortalidade. Quanto à sobrevivÃncia de adultos de pulgÃo, verificou-se que o Ãleo de funcho a 1%, extrato de funcho a 10% e o extrato de cravo a 10% apresentaram os menores Ãndices de sobrevivÃncia, ou seja, 46%, 53% e 53%, respectivamente. No teste de mortalidade realizado na cultura, observou-se a efetividade do extrato de cravo a 10% e do Ãleo de funcho a 1%, em que os mesmos obtiveram 6% e 8% de sobrevivÃncia de adultos de pulgÃes, respectivamente. A anÃlise sensorial das couves nÃo indicou diferenÃa significativa entre as mesmas, a 5% de significÃncia.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