AN EXTRACT FROM Asphodelus aestivus BROT. SHOWING TOXICITY AGAINST Tetranychus cinnabahnus BOISD., THE CARMINE SPIDER MITE

摘要

In this study, we evaluated an extract from the root part of plant Asphodelus aestivus Brot. against Tetranychus cinnabarinus Boisd. under laboratory conditions. The extract not only has mortality, but it also reduces the number of eggs laid and number of eggs that hatched. The root extract of the plant was tested at two different times of the year (November and May) and it was toxic and found to have an LC_(50) of 0.5 g/ml. In comparison tests with the synthetic chemical compound dicofol (trade name, Kelthane), the root extract proved to be more toxic in May than in November. The percentage mortality was 46.6% and 50% within 24 h of application in November and May and it reached the highest levels of 57.1% and 87% after 96 h, respectively. Mite treated with the extract laid a significantly smaller number of eggs by 96 h after exposure than did control mite. The results show that the root extract of A. aestivus has potential acaricide activity, and that its use may reduce undesirable side effects, health problems, and environmental pollution associated with synthetic chemicals currently used in pest management programs. Further research is needed to identify the bioactive compound(s) in the extract and determine the range of crop pests and natural enemies that the extract affects.