The effectiveness of ten concentralions, i.e. 4000. 2000. 1000, 500, 250.
100, 50, 25, 10 and 5 ppm of the botanical insecticide Neemazal-W (powder
contains 10 % Azadirachiin) and Katel-Sous dust at ils recommended rate (1 O/e)
was investigated in the laboratory against the third instar larvae of Trogoderma
granariurn Everts. Mortality was assessed at 1. 2.3.7. 14,21.28 and 35 days
post-treatment .
Results showed nearly lOt) % larval mortalities for Neeniazal at higher
concentrations and Katel—Sous at ، % after 21 days from treatment, while
natural mortality among untreated larvae was 18.33 % and 26.66 % aller 21 and
28 jays, respectively, The survived larvae in the control (73.34 %) developed to
pupae and emerged to adults, while none of Neenmzal treated larvae succeeded
to reach the pupal stage at all tested concentrations.
Increasing Neemazal concci1rations over 250 ppm did not cause au
obvious rise in larval mortality at 21 days post—treatment.
However, lower Necunazal concentrations (5-25 ppm) exhibited
significantly lower mortality values (56—80 %) iii comparison to the values (95—
100 %) achieved at higher concentrations. The survived larvae became very
small in size and showed clearly reduction in their average nican . weight
compared with the untreated larvae, which indicates the antifeedant effect of this
plant compound.
Moreover, Neemazal proved high protective effect to wheat grains
agaïnst the third instar larvae of Khapra beetle.
Meanwhile, ut showed a slight toxic clThct on the uionc feedent larval
stage (diapausing larvae), when tested at lOO. 20. 5(10 and 1000 ppm, as