Scolytidae in pine plantations: Overviews and situation in Brazil

Abstract

Scolytidae are among the most destructive conifer forest pests throughout the world. The phleophagous species (bark beetles) are the predominant group in temperate regions, where they cause millions of dollars in losses in outbreak years. Xylomycetophagous ambrosia beetles predominate in the tropics, and they cause, when compared to bark beetles, less damage, and it is more difficult to quantify. In Brazil, ca. 35% of the reforested area is occupied by tropical and subtropical Pinus species, all of which exotic. Scolytid beetles are growing in abundance and diversity in these forests, but to date no attacks on live trees were registered. While the host selection mechanism for some bark beetles, including primary and secondary attraction, has been studied intensively, host-selection behavior for the ambrosia beetles has generally received little attention. Several ambrosia beetles are known to respond to the kairomone ethanol (primary attraction), but recent experiments showed that some species also respond to other pine host kairomones, alone or in combination with ethanol. Secondary attraction in ambrosia beetles is reported in very few species, none of them in the tribe Xyleborini, which comprises the majority of the most abundant Brazilian scolytid species. Monitoring in Brazilian forests has been traditionally conducted by the use of vane traps, baited with ethanol. However, there are clear indications that some other trap type models, combined with different lures, are more efficient in trapping certain species of scolytids.