Survival and fecundity of three insects reared on four varieties of Scotch pine Christmas trees.
Dioryctria zimmermanni, Neodiprion sertifer and Chionaspis pinifoliae were reared on 4 varieties of Scotch pines (Pinus sylvestris). Survival and fecundity of each species were evaluated in 1994 and 1995 in Michigan. The varieties tested were Riga, Belgium, Land O'Pine, and Pike Lake Improved. Survival and fecundity of D. zimmermanni did not differ significantly among varieties. Larval mortality ranged from 70 to 100% and was attributed to poor establishment on host trees, parasitism by Exeristes comstockii and Hyssopus rhyacioniae, and infection by Hirsutella nodulosa. N. sertifer reared on Riga trees had significantly lower survival, needle consumption, and pupal weight, and a longer development period than those reared on the other varieties. The ichneumonid Pleolophus basizonus parasitized 30% of N. sertifer pupae in 1994. Abundance and fecundity of C. pinifoliae reared on Belgium and Land O'Pine were significantly lower than those reared on varieties Riga and Pike Lake Improved. Results indicated that none of the varieties tested was resistant to all 3 pests.