Résumé:
Polyphenols are widely ranged in plants; some of them play a part in the chemical defense of plants and protect them against herbivorous insects. The absence of the damage on the spring growth seems to indicate a chemical action of Citrus against Phyllocnistis citrella. The aim of this work is to study the effect of crude phenol extract on the larval development of Phyllocnistis citrella Stainton. Young leaves were randomly collected, every week, from spring flushes of Citrus sinensis. A phenol solution was prepared to treat larvae of P. citrella in vitro. Two methods of treatment were adopted; pulverization and irrigation method. The results showed 54.66% of mortality by pulverization and 82.66% by irrigation method, 72h later. The antibiosis action was fast, especially by irrigation method (44% of mortality after 6h). The youngest larval instars (L1 – L2) seem to be more sensitive, when treated by irrigated method, with 97.37 – 97.14 – 51.02% of mortality for 1st, 2nd and 3rd instars larva, respectively. An anti-feeding effect on larvae treated by irrigation method were observed (on 1st, 2nd and 3rd instars larva were 94 - 88 and 68%, respectively). Phenols of orange leave present toxic and anti-feedant activity against P. citrella.
