Development of Anthonomus signatus
Studies on the biology of Anthonomus signatus (EPPO A1 quarantine pest) have been undertaken in Canada. It was found that the sexes of the pest can be easily distinguished and that a constant sex ratio of 1:1 can be found in spring and summer. The maximum abundance of eggs is at 385 degree-days (DD), first instar larvae at 664 DD, second instars at 750 DD, third instars at 922 DD, pupae at 1223 DD and adults at 1465 DD. These degree-days were calculated from 1st of April with a 0ø C threshold. First instars reached their maximum abundance at the beginning of petal fall of strawberries, second instars peak at the first green fruit and third instars when the first ripe fruit can be observed in the field. The population of summer adults starts to appear about the time of the first green fruit and increases rapidly as the last strawberry pick approaches. The development time from egg to adult is approximately 63 d. Adults enter a diapause at the beginning of August. Field observations showed that the spring emergence of adults is not gradual but sudden with a tremendous increase within a very short period of time.
Sources
Mailloux, G.; Bostanian, J. (1993) Development of the strawberry bud weevil (Coleoptera: Curculionidae) in strawberry fields.
Annals of the Entomological Society of America 86, 384-393