The influence of damage level in Pinus sylvestris foliage on the performance of diprionid sawflies. Accepted Oct. 2, 1991. Scand. J. For. Res. 7: 249-257, 1992 I tested the presence of rapid and delayed induced resistance in Pinus sylvestris L. by biotests, rearing three species of diprionid sawflies on defoliated and undefoliated trees. I damaged the pines artificially by cutting mature needles with scissors at the beginning of the growing season. Four levels of defoliation were created on the basis of levels of removed needle biomass. Sawfly larval and cocoon weights were retarded and relative growth rates delayed as a result of an increase in damage level. The larval periods were prolonged at most 2-6 days. The response to the damage was partly species-specific. The needle water content decreased in the following growing season in connection with low and moderate damage and increased at high damage levels. The nutrient contents of the foliage in the damaged and undamaged trees did not differ significantly. The Scots pine showed damage-induced changes in food quality after extensive defoliation, which affected, via plant, species using the same host.
The delayed induced herbivore resistance of the Scots pine (Pinus sylvestris L.) was studied by biotests in which two species of diprionid sawflies (Miuodiprion pallipes and Gilpiniu pallida) were reared on mature foliage of undefoliated and previously defoliated pines. The damage was caused either naturally with larval groups or artificially by cutting the equal amount of foliage biomass with scissors. The trees divided into young and old ones. In most cases the males reared on young pines foliage remained smaller, and the larval groups on these trees grew slower than the groups on older pines. The larvae on the damaged trees pupated later in almost every experiment. Pinus sylvestris was not as sensitive to lower damage as deciduous trees nor did it have the ability to respond to different damage modes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.