Minimizing pest damage to poplars grown under FSC certification guidelines through clone selection, management practices, and pest specific control strategies

Avoidance of clones susceptible to endemic pest species in western North America is complicated by abiotic conditions. Native Populus trichocarpa has a deep rooting system to withstand high winds and periodic droughts, but native riparian areas harbor pests attacking P. trichocarpa and various species of Salix. Clones with trichocarpa parentage chosen for their rooting structure are targeted by all endemic pest species. Trees older than three years are attacked by Prionoxystus robiniae, and younger trees are more susceptible to Paranthrene robiniae. Cryptorhynchus lapathi were significantly more successful at establishing a population in clones with P. trichocarpa x P. deltoides (TxD) parentage (♀ x ♂) than in either of clones with P. deltoides x P. nigra (DxN) parentage, or a clone of P. deltoides x P. maximowiczii (DxM) parentage. Timing of harvest prior to pest emergence reduces the pest population. Chipping operations should be centralized in one location to reduce point sources of plant volatiles that are attractive to Pa. robiniae females. Pruning activities in months when pests are dormant minimizes release of attractive plant volatiles. We have conducted research supporting the new registration of eight insecticides for the protection of hybrid poplars grown under Forest Stewardship Council’s certification program. These protection strategies include insect growth regulators, pest specific systemic insecticides delivered through the drip-line, and chemicals with novel modes of action. Sex pheromones are used to removed the male population through mass-trapping efforts, or disrupt mating of specific pest species.