DefinePK

Abstract

ABSTRACT Blue pine die-back is a very serious disease and apparently healthy looking trees collapse within few days. Four bark beetles species viz. Pityogenes scitus B., Ips longifolia Stebb., Scolytus major Stebb. and Polygraphus major Stebb. were present in blue pine tree infected with die-back disease. However, it was observed that the bark beetle, Pityogenes scitus B was most frequently found in infected trees while Ips longifolia Stebb., Scolytus major Stebb. and Polygraphus major Stebb. were less in number. All the species were found to attack on weakened and severely stressed, wind-blown or wind-broken trees or logs. Attacked is followed by rust causing fungus on the dead and dying trees. All the bark beetles species made the holes of various sizes in twigs, branches and tree trunk and made galleries of different shapes and sizes beneath the bark which made longitudinal tunnels in affected part.