Effect of plant extract Peganum harmala against the whitefly, Bemisia tabaci (Homoptera: Aleyrodidae), at Doucen, Biskra oasis, Algeria
To minimize the side effect of chemical use against pests in greenhouses, a survey was conducted at Doucen, Oasis of Biskra, by applying plant extract of Peganum harmala (Zygophyllaceae) against the whitefly Bemisia tabaci (Homoptera: Aleyrodidae), one of the most devastating pests on tomato crops in greenhouses. Extracts were sprayed on the first, the second and the sixth day. Three different extracts were used; seed extract, oil extract from the seed and extract from dry leaves, with three concentrations (0.25, 0.5, 1.0 ml/ml). Extracts were tested on different larval stages and on adults under laboratory or field conditions, during the autumn and winter period of the year 2008. Results showed that the mortality level increased with increasing extract concentration, especially on the first and second larval stages. The high cumulative level of adult mortality was found 72 hours after oil extract treatment, with 96% adults mortality under laboratory conditions and 72% adults mortality under greenhouse conditions.
