Neelannavar, T.N., & Chavan, M.R. 2004 Influence of Seed Origin on Scale Insect (Maconellicoccus hirsutus) Damage and Severity in Teak Provenance Trial.. Proceedings of the 4th International Crop Science Congress, Brisbane, Australia, 26 Sep – 1 Oct 2004

Notes: Scale insect damage was observed in an international teak provenance trial conducted at Forest College & Research Institute, Mettupalayam (Tamil Nadu, India) located at 11° 19' N and 76°56' E involving 29 half-sib families with three replications (9 plants in each). The study revealed that there was a profound influence of original locations of seed sources on the per cent damage incidence, number of scales per plant, damage severity index, seedling vigour and per cent seedling mortality. The clustering of seed sources for these traits resulted in five clusters with maximum of 15 seed sources in cluster-1 and 8 in cluster-5 leaving the rest three clusters with 2 seed sources each. Seed sources in cluster-5 were found to be most tolerant to scale insect damage with mean cluster value of 19.443 % while cluster-2was found to be most susceptible with mean cluster value of 35.182 %. The clusters 5 & 2 were found to be most divergent (4.588) and clusters 4 & 2 were nearest ones (2.292) with respect to inter cluster diversity. Cluster-5 contained maximum diversity (4.732) within cluster. A strong and significant association was observed for per cent damage incidence with Number of scales per plant (0.406), damage severity (0.395) and teak seedling mortality (0.411). Also a significant correlation was recorded between per cent seedling mortality and scale insect damage severity index (0.434). Number of individuals per plant showed maximum (0.597) positive association with scale insect damage severity index. The study signifies the importance of seed origin in selection and breeding for insect tolerance/resistance in important tree species.