Resistant and susceptible pine (Pinus thunbergii, Parl) trees to pine gall midge (Thecodiplosis japonensis, Uchida et Inouye) were selected and monoterpene composition in one year old branches, shoots and needles of both groups have been analysed by GLC.
The results are summarized as follows;
1. Monoterpene composition in either one year old branches or shoots were not affected by their directions (North or South).
2. Major monoterpenes in one year old branches were α-pinene, β-pinene, myrcene, limonene, β-phellandrene and terpinolene.
3. In addition to a-pinene, camphene, β-pinene, myrcene, △³-carene, limonene, β-phellandrene and terpinolene, several less volatile components which appear to be monoterpenes were also present in shoots and needles.
4. Compared with the susceptible pine, the resistant tree was found richer in limonene composition.
5. β-Pinene composition in the resistant pine was less than that in the susceptible pine. 6. The difference in the composition of limonene or β-pinene between two groups of pine trees was discussed in relation to the resistance to pine gall midge.
|