Sassafras Weevil
Odontopus calceatus
A small dark weevil, better known as the yellow poplar weevil, that feeds on sassafras, tulip poplar, and magnolia. The adults chew distinctive rice-grain holes in the leaves and the larvae tunnel blotch mines inside them, and in outbreak years the combined damage can make whole trees look scorched.
🔎 How to spot it
The adult is a tiny dark weevil about a fifth of an inch (5 mm) long with lighter brown legs, a short stubby body whose head and thorax are narrower than the abdomen, and lengthwise grooves down the wing covers. The larva is a pale, legless grub with a brown head capsule that lives inside the leaf. Adult feeding leaves small, crescent-shaped holes about the size of a grain of rice; the larvae make brown blotch mines, usually starting at the leaf tip.
🥀 Damage it causes
Adult feeding peppers the leaves with little crescent holes, while the larvae mine brown blotches inside the leaf, often at the tip. When numbers are high the holes and mines run together so leaves wilt, brown, and die and a heavily infested tree looks burned from a distance. Despite the dramatic look, established trees shrug off a year or two of heavy feeding without lasting harm.
🛡️ Prevent it
On large landscape trees damage is cosmetic and no action is needed; keep trees healthy so they can outgrow it. Where protection is wanted, watch for the first crescent feeding holes in spring as overwintered adults become active, since catching the adults before they lay eggs prevents the leaf mining that follows.
🧯 If it is already here
Time any foliar spray for May, when the overwintered adults are feeding and laying eggs, to head off the larval mines; a second window is July, when the new adults feed before retreating for the season. A spring systemic insecticide can protect against both the larvae and the next round of adult feeding. Most yards never need treatment.
💡 Good to know
There is one generation a year. New adults emerge in early June, feed, then retreat to the leaf litter by midsummer and rest there through winter; mating and egg-laying happen in May and early June, with eggs inserted in the midrib on the leaf underside and larvae mining for three to four weeks. Besides sassafras it is a major pest of tulip poplar and is also called the magnolia leafminer.
🌱 Plants it attacks
6 plants in the library can be attacked by this pest
For educational and informational purposes only. Pest control advice is general guidance drawn from university cooperative extension sources; always identify a pest positively and read and follow the label on any product before use, especially around food crops, children, and pets.