Interaction of olive trees and Psylla: Characterization of phenol compounds from new shoots and flower buds and relation to the degree of cultivar resistance

This is the first study showing evidence of the production of phenolic comp ounds in Olea europea L, young and flower buds in response to attack by Eup hyllura olivina Costa (Psylla). Quantitative differences of phenolics were recorded in young and flower buds from 7 cultivars differing in their resis tance to Psylla. A certain degree of resistance to Psylla of young and flow er buds was associated with their higher level of soluble phenolic compound s. Among several phenolics characterized, 3,4 dihydroxyphenylethanol seems to be positively related to the repulsion of cultivars to Psylla, Indeed, t he more attractiveness of insect by flower buds may be in part explained by their phenolic levels 2 to 3 times lower than in young buds, ft has been s hown that the attack and the loss of the plant material caused by Psylla ar ise during period of the loir er level of phenolics in tissue, The role of phenolic compounds in the resistance of Olea europea to Psylla is discussed .