Catches in synthetic sex pheromone-baited traps of lepidopterous males infesting fruit trees in relation to their dispersal activities.
The suitability of traps baited with the synthetic female sex pheromone of Grapholita molesta [Cydia molesta], Archippus breviplicanus [Archips breviplicanus] or Carposina niponensis in monitoring the movements of males in the vicinity of fruit trees was determined in field tests in Ibaraki Prefecture, Japan, in 1978-79. No males of Cydia molesta were caught when their sex pheromone was used with that of A. breviplicanus in the same traps. A. breviplicanus males were not caught in any of the traps used. In the case of either C. molesta or Pammene nemorosa, which were frequently caught in the C. molesta traps, curves depicting the trend in the cumulative percentage of daily catches in summer and autumn did not show significant differences between areas of Japanese pear [Pyrus pyrifolia] and chestnut. This indicated that the dispersal behaviour of males of both species could be traced over wide areas in different types of environments, including areas of chestnut, which is not the usual food-plant of C. molesta. It is suggested that, in summer and autumn, C. molesta males invaded areas of Japanese pear, which contained young trees with a thin canopy. Carposina niponensis males were caught in areas of either Japanese pear or chestnut, though the total catch in all areas was small.