Pristiphora erichsonii

A number of diterpenes are known to be active against herbivores ( ). The diterpenes abietic, dehydroabietic, 12-methoxy-abietic, sandaracopimaric, and isopimaric acid serve as feeding deterrents for the larch sawfly, Pristiphora erichsonii in single needles from new shoots of tamarack (Larix laricina) (133). The larvae of this insect do eat tufted needles on short shoots of the same trees. 

Ohigashi, H., M. R. Wagner, F. Matsumura, and D. M. Benjamin, Chemical basis of differential feeding behavior of the larch sawfly, Pristiphora erichsonii (Hartig), J. Chem. Ecol., 7, 599-614 (1981). 

The most destructive insect pest of tamarack is the larch sawfly (Pristiphora erichsonii). Periodic epidemics of this defoliator occur across Canada and the northern United States. Another serious defoliator of tamarack is the larch casebearer Coleophora laricella). Severe outbreaks have caused extensive mortality of trees of all ages (Johnston, 1990). 

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