Possibilities of biological control of Cacyreus marshalli
Cacyreus marshalli (EPPO A2 quarantine pest) was introduced into Europe in 1989 (and probably earlier) in Menorca, Baleares (ES – see RS 520/03, 1992), and then spread to continental Spain (RS 94/033), Italy (RS 97/139) and France (98/080). This pelargonium pest continues to spread, and Sarto and Gabarra (1998) mention that C. marshalli appeared in 1997 in East Sussex (UK) and that it occurs in Morocco. The exact status of the record in UK is under investigations by the British National Plant Protection Organization, which does not consider that the pest is established. The reported Moroccan record is new. So far, no potential biological control agents had been found in Europe and only chemical control has been applied. This raised difficulties, as many attacked plants are grown in private gardens. However, in September 1997, 20 to 30 eggs of C. marshalli were collected from Pelargonium peltatum in Cabrils (ES) and a few of them gave rise to adults of Trichogramma evanescens. This was also observed from parasitized eggs collected in Lleida. Although further studies are necessary to evaluate the potential of T. evanescens to control C. marshalli, the authors felt that for the first time since the introduction of this pest into Europe possibilities for biological control can be envisaged.
Sarto, V.; Gabarra, R. (1998) Un Himenòpter parasitoid d’ous del barrinador del gerani.
Catalunya Rural i Agrària, no. 46, 24-26.