Bio-insecticidal activities of halophytic plant extracts against Tribolium confusum (Coleoptera, Tenebrionidae).

Salt marsh plants were tested for their insecticidal activities against larvae of the confused flour beetle Tribolium confusum (Tenebrionidae). 16 aerial part extracts were obtained using organic solvents of increasing polarity and tested for their anti-feedant and toxicity effects. Responses varied with plant material and extract type. Ethyl acetate extracts of F. laevis, S. echioides and. T. boveana and petroleum ether extract of F. laevis presented, anti-feedant property. However, S. fructicosa seemed to be attractive to the tested flour beetle. Mortalities of 97, 87, 97 and 80% were observed by using respectively ethyl acetate extracts of F. laevis, S. echioides and T. boveana and petroleum ether extract of F. laevis, when applied at a dose of 1%, mixed with the insect diet. This preliminary study showed that F. laevis, S. echioides and T. boveana presented potential bio-insecticidal activity with ethyl acetate extracts, similar result was found with petroleum ether extract of F. laevis. More complementary studies are needed for the use of these extracts to control T. confusum.

Bioactivities of seven chrysanthemum species flowers powder on Spodoptera littoralis (Boiduval) larvae.

We have screened seven Chrysanthemum species, collected from different biotope in Tunisia for the antifeeding and growth regulatory activity against S. littoralis (Lepidoptera: Noctuidae) an insect pest of tomato. The flowers powder was added to the Poitout and Bues (1974) artificial diet at three concentrations: 4, 8, and 16%. After ten days of treatment, the consumed quantity determination revelled that these species have an antifeeding activity proportional to the concentration, more considerable for the C. fuscatum and C. Myconis flowers powder. At the concentration of 16% the larvae weight was significantly delayed in the average time to the control, these results were compared to the effect of Cestrum parquii on S. littoralis and Pieris brassicae The moulting date determination showed an elongation of the third, fourth and fifth stages at the high concentration probably due to the presence of juvenile hormones Analogues.