Reproduction and longevity of the cabbage aphid [Brevicoryne brassicae (L.)] after exposure to ethanolic extract of clove (Syzygium aromaticum L.)

Botanical pesticides are an important group of naturally occurring, often slow-acting crop protection that are usually safer to humans and the environment than conventional pesticides, and with minimal residual effects. Therefore the use of plant pesticides has been recommended ever more as a suitable alternative of plant protection with minimum negative risks [1, 2]. Especially botanical insecticides have long been a subject of research in an effort to develop alternatives to conventional insecticides. Therefore, this research was conducted to assess the effectiveness of ethanolic solution (30mg/ml) of clove flower buds extract (Syzygium aromaticum L.) on reproduction and longevity of the cabbage aphid [Brevicoryne brassicae (L.)] in the laboratory.

In this experiment, 50 newly 1st nymphal instars of the cabbage aphid were placed together into the round plastic Petri dishes on rape leaves and sprayed with the ethanolic solution. In control treatments only ethanol (95%) were applied. After 24 hours, the nymphs were transferred into the new Petri dishes with fresh leaves and reared until the adulthood. Afterwards, the adults were confined singly in other Petri dishes and reared until death. During the longevity experiments, reproduction of the adults was estimated during one week. The ethanolic plant extract caused a significant reduction in longevity of the adults (8.7 days) when compared with the control treatments. Moreover, the plant extract had a significant deleterious effect on the mean total number of laid nymphs during the seven days with the mean of 5.8 nymphs.

Keywords: Brevicoryne brassicae, plant extract, Syzygium aromaticum, Reproduction, longevity

References: 1. Isman MB (2006) Ann Rev Entomol 51: 45–66.

2. Pavela R (2007) Pest Technol 1: 47–52.