Controlling Tuliptree Scale on Yellow Poplar

Blackened leaves and bumps on twigs indicate tuliptree scale (Toumeyella liriodendri). The bumps are female scales sucking sap; their honeydew excretion grows sooty mold. Control requires two steps: spray crawlers in fall with a hose-end sprayer using bifenthrin or similar, then apply horticultural oil in late winter (Feb–Mar) to suffocate overwintering scales.

Repeat for two consecutive years. The oil must coat the scales thoroughly. This combined approach breaks the life cycle and restores tree health.