Yellow poplar weevil, also known as sassafras weevil, is a small (1/8”), stout, black, snout beetle that can damage yellow poplar, sassafras, and magnolia. In spring, adults can be found on these trees or, when numerous, in buildings and on some other plants. They chew distinctive holes in leaves of their preferred hosts; these look like puffed rice grains in size and shape. While on occasion, adults and larvae can cause significant leaf loss, damage to established trees does not affect overall tree health.
Yellow poplar weevil overwinters as adults in leaf litter and other protected harborages. They become active and start to feed on warm days in late April and early May. Adults attack the swelling buds and leaves as they unfold and enlarge, leaving holes of about 1/8″ in diameter.
There is one generation per year with the next generation adults emerging in early June to feed on foliage. Sometimes they chew through leaves, but more often, they chew only partway through a leaf, so the upper layer remains intact (Figure 1). This produces many chlorotic spots and results in the scorched appearance of severely attacked trees. Feeding by newly emerged weevils can be severe. By mid-July adults have moved to their hiding places in leaf litter and will remain inactive until spring.
Insecticides may be used to reduce damage to the foliage. Treat when feeding damage is seen on about 10% of the branches, and repeat applications as necessary. Weevils arrive at trees over an extended period; treating at the very first sign of damage may be too early and require an additional application in a few days. While the damage may be unsightly, injury to large, established trees in landscapes or wooded areas probably will not harm trees.
Ric Bessin, Extension Entomologist