LARGE INFESTATION OF CHESTNUTS BY CYDIA MOTHS IN MADEIRA ISLAND: MONITORIZATION OF CYDIA SPLENDANA POPULATIONS WITH PHEROMONE LURES

Abstract

Chestnut fruits represent an important economic income for local populations of Madeira Island. In the last years chestnut fruits have been heavily attacked by an unknown moth species. Since C. splendana -a carpophagous species common to chestnut fruitshas been reported to Madeira, three different commercial pheromones lures (Agrisense, Tomagro, and Oecos) have been used to monitorize this species in three different localities. The subtropical conditions on this island seem to affect the phenology of populations. Large numbers of Cydia splendana, were sampled from August to mid November but the period of flight activity was longer than in continental areas. The peak of flight activity was comparatively late from the end of August to beginning of September. Oecos was the most efficient pheromone lure in the three localities studied. The infestation rates of fruits were large and varied from 13 to 40% but coloration and chetotaxia of larvae did not correspond to Cydia splendana. The variation observed in larvae in these structures can represent either patterns of instraspecific variation or the coexistence of different species. Further morphological studies should be done. INTRODUCTION Three species of carpophagus tortricids are responsible for great damage in chestnut production in Europe: Pammene fasciana, Cydia splendana and Cydia fagiglandana. Of these three species, only one, Cydia splendana has been reported to Madeira. Native vegetation of Madeira is different from continental Europe being represented mainly by an evergreen laurel forest, considered a relic of the tertiary age. As occur in the archipelagos of Canaries and Azores, chestnuts are not native in Madeira. They have been introduced after the colonization of the Island in the XV century. Presently this culture is restricted mainly to very steep slopes of the southern parts of the Island and although occupies a relative small area (<50 ha), represents for local populations an important economic income. In the last years chestnuts have been heavily attacked causing important losses to fruit production. Despite of this, due to the absence of knowledge on the pest species involved and to the very irregular orography of the chestnut localities, efficient phytosanitary measures were not