Carnivorous or insectivorous plants belong to several botanical
families, the most important of them is Droseraceae, which includes Drosera
plants. Insecticide substances are extracted from Drosera. Tissue
culture technique provides the best way to obtain as high and clean quantity
as possible of the biomass needed to obtain these substances. This study
aimed to propagate the Drosera capensis in-vitro and studying the effect of
Drosera capensis residue on larva of red palm weevil. Shoots were visible
on leaf explants, apparently forming directly on leaf surfaces without intermediate
callus.
The best results of shoot number (13.8 shoots per explant) and
length (2.93 cm) were obtained at 0.05 mg L-1 BA compared with the control,
BA-free media, observed 2.8 shoots per explant and 2.27 cm in length.
Shoots were sub-cultured on half strength of MS medium supplemented
with four concentrations of IBA (0, 0.5, 1.0, 2.0 mg L-1) in rooting
stage. MS basal medium supplemented with 1.0 mg L-1 IBA achieved the
best root formation where the root number was 47.3 per plant. The residue
of Drosera capensis plants at different concentrations (0.0, 50.0, 100.
500.0 mg per liter) had been given to fully developed larvae of red palm
weevil (Rhynchophorus ferrugineus Oliv.) through their feeding diet. Larvae
were obtained from the field and were maintained on the stems of sugarcane
prior to mass rearing, artificial diet, which was formulated from
sucrose, molasses, potatoes and agar. The residue of Drosera capensis
had toxicological effects on R. ferrugineus larvae. The lethal action of
Drosera capensis residue had appeared clearly at 500 mg L-1 where the lethal
percentage of red palm weevil larva was 65% after ten days.