Oleoresin crystallization in eastern white pine: relationships with chemical components of cortical oleoresin and resistance to the white-pine weevil

Abstract

Natural and weevil-larva-induced crystallization of oleoresin from 45 eastern white pine trees with known resin acid and monoterpene composition, and from 59 pairs of nonweeviled and heavily weeviled trees from the same seed sources, was examined in mid- and late spring. Very little difference was found between larva-induced and natural crystallization. Strobic acid-usually the major resin acid found in the cortical oleoresin of eastern white pine-was positively correlated with the rate and extent of crystallization. Crystallization of oleoresin from the same trees varied greatly between sampling dates, but oleoresin from white pines with concentrations of strobic acid of less than 5 percent did not crystallize even after 3 to 10 days from the time of collection. Trees with high concentrations of strobic acid had oleoresin that crystallized within 4 hours. Concentration of sandaracopimaric acid was also positively correlated with crystallization. Concentrations of abietic and neoabietic acids, when expressed as proportions of the total resin acids, were negatively correlated with crystallization. None of eight monoterpenes was consistently related to crystallization properties. Variation in crystallization reactions is not useful as a selection criterion for weevil resistance. Although noncrystallizing oleoresin was found more frequently among heavily weeviled trees than in nonweeviled trees, the differences were small and not significant. Eastern white pine trees with oleoresin that does not crystallize are rare. Only eight trees had oleoresin that did not crystallize after 3 to 10 days from both sampling dates, and of these, six had been heavily weeviled. Most potential candidates for resistance breeding programs would not be selected because 58 percent of the trees that had resisted weevil attack had oleoresin that crystallized after 4 hours and 97 percent had oleoresin that crystallized after 3 days.

Citation

Wilkinson, Ronald C. 1979. Oleoresin crystallization in eastern white pine: relationships with chemical components of cortical oleoresin and resistance to the white-pine weevil. Res. Pap. NE-438. Broomall, PA: U.S. Department of Agriculture, Forest Service, Northeastern Forest Experiment Station. 10p.