SUBLETHAL EFFECTS OF FENNEL AND PENNYROYAL EXTRACTS ONBIOLOGICAL PARAMETERS OF OMMATISSUS LYBICUS DE BERGEVINAzita Dehghan, Arezoo Payandeh, Sohrab Imani, Mahmood Shojai and Hadi Ostovan
A serious pest of the date palm (Phoenix dactylifera L.) in Iran and other countries with date palm orchards is the Dubas bug (Ommatissus lybicus De Bergevin). In this study, we used the age-stage, two-sex life table theory to evaluate the sublethal effects of the extracts from medicinal plants including fennel (Foeniculum vulgare Miller, Apiaceae or Umbelliferae) and pennyroyal (Mentha pulegium L., Lamiaceae or Labiatae) on life table parameters of Dubas bug. The biological parameters were studied at 30±1 °C, 60±10% RH, and a photo-period of 16:8 (L:D) h. Our results show that the extracts caused in significant decreasing of fecundity, oviposition days and pre-adult survival rate of Dubas bug. Furthermore they brought about in increasing of pre-adult developmental time, but the adult developmental time was decreased by using the extracts, significantly. The total longevity of Dubas bugs was decreased extracts treatment, significantly. Extracts also decreased the life table parameters including r, λ and R0, significantly. The survival rate of Dubas bug was decreased by using the extracts treatment. The lowest age-stage survival rate was observed in pennyroyal treatment. In addition, mx, exj was the lowest in pennyroyal treatment. Our results showed that the pennyroyal extracts was more effective than fennel extracts on biological parameters, survival rate and fecundity of Dubas bugs.
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