Effets biologiques de quelques plantes spontanées du Sahara septentrional Est algérien sur la cochenille blanche Parlatoria blanchardi Targ. du palmier dattier dans la wilaya de Ghardaïa

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.).