Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Distribution of pine needle gall midge, Thecodiplosis japonensis Uchida et Inouye (Diptera: Cecidomyiidae), infestations on Japanese red pine, Pinus densiflora S. et Z.

Abstract

The distribution of Thecodiplosis japonensis infestations was analysed from data collected in young Japanese red pine (Pinus densiflora) stands during 1992 and 1995-96 in Kangwon-do, Korea Republic. No significant differences in percentages of infested needle pairs were found between trees or between terminal and lateral shoots within a tree. However, the mean percentages of infested needle pairs increased significantly from the lower crown to the upper. Percentages of infested needle pairs on sample units, consisting of 1 terminal and 2 lateral shoots, in the midcrown were the better predictors of whole-tree percentages than were other crown levels. Therefore, a sample unit consisting of 1 terminal shoot and 2 lateral shoots as branch were fixed from the midcrown level. Numbers of tree and sample unit combinations needed to estimate T. japonensis infestations with two levels of precision were determined.