Effect of ethanolic extract of Melia azedarach L. seeds on oviposition and egg hatching of Tetranychus urticae (Acari: Tetranychidae)

Tetranychus urticae Koch is one of the most important pests of crops, ornamental and greenhouse plants in the world and, can damage to 900 plant species. Resistances to pesticides and acaricides have guided researches to introduce new methods to control T. urticae. Botanical pesticides are an important group of natural productions that are usually safer than conventional pesticides for humans and the environment. Extracts of genus Melia have insecticidal and anti-nutritional effects. The effect of ethanolic extracts of M. azedarach seeds on eggs hatching (hatching time & hatching rate) and egg-laying of T. urticae were investigated under laboratory conditions.Experimental: Treatments included the ethanolic plant extract (36 mg/ml) and control (ethanol 95%). The sub-lethal effect of the plant extracts was determined using a spraying bioassay. The duration of egg stage of T. urticae after exposing to plant extracts were significantly longer than control treatment with a mean±SE of 5.24±0.05 and 4.85±0.04 days, respectively. In control treatment, hatching rate of the spider mite eggs was significantly more than in plant extract treatment. The ethanolic plant extracts had significant deleterious effects on the oviposition behavior of the spider mite. So that, during four days of the experiment, the mean±SE of total oviposition of the mites was 2.95±0.65 and 12.17±1.33 in plant extract and control treatments, respectively.Industrial and practical recommendations: According to this result, substituting conventional pesticides with ethanolic seed extract of M. azedarach can be useful. However, formulating the plant extract is essential for commercial use of the acaricidal extracts. Therefore, it needs more scientific studies levels.