Light‐trap Catches of Fruit Tortricid Moths in Kent, 1964–74, and Associated Temperature Sums

Abstract

SUMMARY Light‐trap catches of five tortricid species were recorded at orchard sites in Kent over an 11‐year period. The dates on which moths of Hedya nubiferana (Haw.), Cydia pomonella (L.) and Archips podana (Scop.) were caught in light traps were strongly correlated with accumulated temperatures in day‐degrees above a base of 8°C. The correlation was less good for catches of Pandemis heparana (Denis & Schiff.) and it was slightly better for those of Cydia pomonella above 10°C than above 8°C. The data were insufficient to calculate temperature sums for catches of Adoxophyes orana (Fisch. v. Rösl.). Moth catches of all five species showed differences between years in the timing of first and second generations. The dates of first catches are compared with dates estimated from the following temperature sums: for H. nubiferana 226 day‐degrees above 8°C, for C. pomonella 268 day‐degrees above 8°C and 149 day‐degrees above 10°C, for Archips podana 326 day‐degrees above 8°C and for P. heparana 386 day‐degrees above 8°C. In the 11‐year period, estimated dates of first catch were within ± 5 days of first actual catch of moths in light traps in nine years for C. pomonella, eight years for H. nubiferana and A. podana, but only five years for P. heparana.