Temperature-manipulated dynamics and phenology of Mindarus abietinus (Hemiptera: Aphididae) in commercial Christmas tree plantations in Québec, Canada

Abstract

The balsam twig aphid Mindarus abietinus Koch (Hemiptera: Aphididae) is a major pest of economic importance for the Christmas tree industry. Global warming during the 21st century could potentially increase local population densities and reinforce the pest status of this aphid in commercial fir (Abies Miller; Pinaceae) plantations in Québec, Canada. During this study, we tested the effects of a warmer environment on colony growth rates of M. abietinus and aphid morph composition during the second generation of its cycle, which is key to colony size growth and potential damage to Christmas trees. We monitored M. abietinus populations on two host fir species and one host fir variety, in order to understand the early season dynamics of this aphid and its host tree. It was possible to distinguish the two overlapping generations of winged aphids leaving colonies, which led to observing a much higher proportion of wingless daughters, produced by the stem mother, than what had previously been reported. Colony growth rates were significantly higher in a warmer environment than in the nearby plantation, suggesting that warmer temperatures in late spring and early summer may provide the suitable conditions required for M. abietinus colonies of greater density.