Abstract:
Our work is aiming to study natural extracts in order to eliminate white mealybugs
(Parlatoria blanchardi Targ) and to find new natural inhibitors of acetylcholinesterase. To do
this, we prepared the aqueous extracts of Cleome arabica and Urtica urens, two spontaneous
plants harvested in the northern Algerian eastern Sahara, on some neurochemical and
behavioral parameters in white scale Parlatoria blanchardi Targ. after treatment. These
solutions were tested in five doses at 20%, 40%, 60%, 80% and 100% on the white scales of
the palm tree. These tests showed that Cleome arabica and Urtica urens showed significant
toxicity against P. blanchardi with very high mortality in terms of dose and time of exposure.
The minimum duration of mortality (TL50) was recorded with Cleome arabica after 4,5 min.
The minimum lethal dose (LD50) is 0.070 g / ml in individuals treated with Urtica urens. In
order to determine the effect of aqueous extracts on the enzyme cholinesterase, we studied the
cholinesterase activity of this enzyme in different doses over a period of three hours after
treatment. We found a lowering of cholinesterase activity after treatment in P. blanchardi
Targ. individuals. This means that the aqueous extracts of Cleome arabica and Urtica urens
cause almost complete inhibition of the white scale (Parlatoria blanchardi Targ.).
