Use of Tanacetum tomentosum and Ta. dolichophyllum essential oils as botanical repellents and insecticidal agents against storage pest Tribolium castaneum (Coleoptera: Tenebrionidae)

In this study, repellent and fumigant activities of Tanacetum tomentosum and Ta. dolichophyllum essential oils were investigated against Tribolium castaneum. Results showed that both oils had effective fumigant and repellent activities. Tanacetum tomentosum oil emerged as more potent than Ta. dolichophyllum oil with LC50 values of 6.85 and 4.32 mu L/0.25L air after 24 and 48h of exposure, respectively. Ta. tomentosum oil also showed more repellent activity than Ta. dolichophyllum oil by exhibiting repellent activity in the range of 38.70-82.35%. Chemical analysis of both oils revealed that beta-bisabolene (50.0%) was the major component of Ta. tomentosum oil and that beta-eudesmol (31.4%) and beta-bisabolol (10.7%) were the major components of Ta. dolichophyllum oil. Doses of 40 and 80 mu L/0.5L air of both oils significantly protected 500 g of wheat grains for up to 6 months from insect infestation, without causing any side effects in the germination rates; the order of germination rates was Ta. tomentosum (89.45%) > Ta. dolichophyllum (86.78%). Thus, this study suggests that essential oils from Ta. tomentosum and Ta. dolichophyllum can be used as potential alternative botanical fumigants for controlling Tr. castaneum.