Communication on the preventive control of Thaumetopoea pityocampa Schiff. (Lep., Thaumetopoeidae) in Thessaloniki, Greece.
Field trials were carried out in Thessaloniki, northern Greece, in 1980-81 to examine the possibility of preventive measures against Thaumetopoea pityocampa (Denis & Schiff.) on pine (Pinus). Bacillus thuringiensis subsp. thuringiensis (Bactospeine), B. thuringiensis subsp. kurstaki (Dipel), diflubenzuron (Dimilin) and triflumuron (SIR-8514) were applied to P. brutia before the beginning of egg hatch. Bactospeine and diflubenzuron caused a reduction in the hatch rate when spraying was carried out 22-23 days before hatching. Up to 30 days after application, a high level of larval mortality was observed (70-100%). The mortality rate was lowest (21%) after application of the lowest dosage of Dipel (75 ml/100 litres water). However, none of the preparations was completely effective against larvae placed on the trees 80 days after treatment, although they caused a reduction in larval weight.