Emergence of the apricot seed wasp Eurytoma samsonowi Vassiliev (Hymenoptera: Eurytomidae) as an economic pest of apricots in Tunisia.

Many eurytomid (Eurytomidae) wasps are plant parasites, and some of them are economic agricultural pests. In 2015, a new eurytomid wasp species was detected attacking apricots in the governorate of Gafsa located in the southern west region of Tunisia. Morphological and molecular identifications allowed to identify the pest as the apricot seed wasp Eurytoma samsonowi Vassiliev, a new record in Tunisia and Africa. Besides, field surveys were performed from 2017 to 2021 in order to assess the distribution of E. samsonowi in the main Tunisian apricot production areas, to characterize its symptoms of attack and to assess its damage on different apricot cultivars. The pest has limited distribution in Tunisia as it was found only in the governorates of Gafsa, Sidi Bouzid and Tozeur. Larvae of this pest feed on apricot nucellar tissues. Infested fruits either prematurely fall on the ground or turn black, become 'mummified', and remain attached to the tree. The highest infestation rates were recorded on Bayoudhi cultivar ranging from 64 to 76% depending on the year. Infestation rates registered on Bedri and Amor Leuch cultivars ranged from 24% to 51% and 27 to 53%, respectively. Therefore, this insect should be considered as an economic pest of apricots in Tunisia. Possible management measures and future outlooks are discussed. [ABSTRACT FROM AUTHOR]