INSECT DAMAGE TO MALE CATKINS, FEMALE FLOWERS AND ACORNS OF QUERCUS SPP IN ROMANIA

Insect damage to male catkins, female flowers and acorns was surveyed from 1979 to 1988 in 2 seed orchards and 9 oak stands selected for cer tified acorn collection in Romania. Four oak species were considered. Nine insect species, mainly Cynipid gall wasps, were found damaging ma le catkins but damage generally remained below 10 %. Only the Cynipid Andricus grossulariae had a limited but constant influence on catkins mortality. Female flowers were attacked by 5 species before fecundatio n and by 7 species following fecundation. Some lepidopteran defoliatin g larvae significantly shifted to female flowers during their outbreak s. The specific cecidomyiid Contarinia amenti also showed damage up to 20 % of the female flowers but the total flower damage did not exceed 15 % in most years. The most significant insect impact ws observed on developing acorns, that were colonized by 7 species. The larvae of th e weevil Curculio glandium regularly damaged more than 25 % of the aco rns when two Cydia larvae attacked more than 10 % of these acorns in m ost crops. The Cynip gall wasp Adleria quercuscalicis showed irregular damage. The resulting total acorn mortality was generally higher than 25 %, and up to 80 % in two crops. No difference was observed among l ocations but damage significantly varied with years in relation with t he annual change in acorn crop.