Bioactivity of cardanol against the rust red flour beetle, Tribolium castaneum (Coleoptera: Tenebrionidae)

Cashew nut shell liquid (CNSL) is an economically important by-product obtained from the cashew nut Anacardium occidentale L. The liquid has been found to be versatile with a wide range of uses, including as a raw material in the polymer industry, in the development of drugs (antioxidants) and in pest control. One important chemical component of CNSL known for its bioactivity is cardanol. We isolated (8Z,11Z)-3-(8,11,14-pentadecatrienyl)phenol, a cardanol from CNSL, and determined its insecticidal and progeny growth and development inhibition activities against Tribolium castaneum Hebst. We used a bioassay-guided approach for the isolation. Exposure to cardanol produced 80% mortality of adult T. castaneum in the insecticidal bioassay. In the progeny growth and development inhibition bioassay, 46.7% of larvae were killed, and only 20.7% of adults emerged without deformities after the cardanol treatment. The amount of isolated cardanol from the 1 g equivalent/ml extracted CNSL was found to be 36.55 mg with LC50 value of 47.88 mg/ml and 13.28 mg/ml against adult T. castaneum and its larvae, respectively. We conclude that cardanol can potentially be useful in managing stored product insect pests, especially T. castaneum, but with the prerequisite that one should take much care when handling and when applying the compound.