Steinberg, S., Department of Entomology, Hebrew University of Jerusalem, Faculty of Agriculture, P.O. Box 12, Rehovot, Israel
Podoler, H., Department of Entomology, Hebrew University of Jerusalem, Faculty of Agriculture, P.O. Box 12, Rehovot, Israel
Applebaum, S.W., Department of Entomology, Hebrew University of Jerusalem, Faculty of Agriculture, P.O. Box 12, Rehovot, Israel

The effect of larval diet on diapause induction in the Israeli strain of the codling moth, Cydia pomonella (L.), was studied in a field trial using intact apple fruits of two varieties: ‘Ana’ (early‐ripening, in the end of June) and ‘Granny Smith’ (late‐ripening, in October). Diapause incidence increased as fruit age (determined as days from fruit‐set) progressed. These results corroborate former studies on other strains of the codling moth, where excised fruits were used. The combination of 80‐day‐old, fully ripe, ‘Ana’ fruit treatment with the longest days of the year, yielded 38% diapause. This result demonstrates that mature fruit (inducing diapause) cannot completely override the effect of long day (averting diapause), but does confirm that larval diet modifies the photoperiodic induction of diapause in the codling moth. 1992 The Netherlands Entomological Society