Effect of Cone Worm, <I>Dioryctria abietella Denis</I> and Schiffermuller (Lepidoptera : Pyralidae) on the Seed Efficiency of <I>Pinus wallichiana</I>

Abstract

Cone and seed worm, Dioryctria abietella damages cones of Himalayan conifers. Infested cones were categorized on the basis of emergence holes into light, moderate, heavy, very heavy and severe intensities. Seed efficiency (S.E.) was found negatively correlated with the degree of attack as the degree of attack increased from light category to severe. The attack of D. abietella also hampered the development of cone, caused direct damage to seed and reduced the germeability of seed. Germination percentage decreased with increased degree of attack. Present studies help in estimating the production of seeds in the SPAs, seed orchards and seed stands of Blue pine.