Controlling the 2nd instar larvae of Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) by simmondsin extracted from jojoba seeds in KSA.
Background and Objective: Tomato leaf miner, Tuta absoluta (Gelichiidae: Lepidoptera) is a destructive pest of tomato crops worldwide. So, the main objective was to evaluate simmondsin extracted from Jojoba seeds against T. absoluta larvae, which are considered to be the most dangerous pests of the family, especially tomato. Materials and Methods: Individuals of the tomato leaf larvae, pupa and adults were collected from green houses and tomato leaves were infested and incubated under lab condition until the emerging of adults. Newly laid eggs (24 h old) were carefully collected from tomato plants that had previously been exposed to T. absoluta adults (both sexes). The effects of simmondsin extracts on mortality were tested using one-way ANOVA and corrected by using Abbott's formula. Results: Several simmondsin extracts were used (by ammonium hydrogine peroxide, isopropanol, acetone, or water at concentrations of 25, 50, 75 or 100%). The result obtained showed that simmondsin extracts by acetone and water significantly reduced (at 5%) T. abslouata populations in comparison with data oblations from simmondsin extracted by ammonium hydrogen peroxide and by isopropanol. A strong correlation between the susceptibilities of T. absoluta populations to extraction methods and concentrations were observed. Conclusion: Simmondsin extractions were more effective in controlling the 2nd instar larvae of T. absoluta. It may be concluded that use of simmondsin extracts could be useful within IPM programs. This finding indicates that biorational insecticides are a good alternative than synthetic ones particularly with fresh vegetables. Possible use of biorational insecticides in the management of T. absoluta in organic farming system is being discussed. Poor-resource farmers of tomato could therefore adopt jojoba extracts as alternatives to synthetic insecticide.