Odontopus calceatus is also known as the sassafras weevil, the magnolia leafminer, or the tulip tree leafminer. This insect, as all of these common names suggest, feeds on yellow poplar (tulip tree; Liriodendron tulipifera), sassafras (Sassafras albidum), magnolia (Magnolia spp.), as well as bay laurel (Laurus nobilis). The yellow poplar weevil is native to much of the eastern United States. Both the larvae and the adults of the yellow poplar weevil will feed on its hosts. Adult weevils are 1/10th of an inch long and brown or black in color. Adults feed on the leaves and buds while the larvae mine the leaves. Adult feeding causes irregular holes to form in the leaves. Yellow poplar weevils overwinter as adults in sheltered areas, such as the leaf litter, around their hosts. In the early spring, they initiate feeding on the buds and newly opening leaves of the host plant. By May, they lay eggs in the midrib of the leaves on leaf undersides. Eggs will hatch and the larvae mine the leaves, creating blotch-like mines. This mining begins at the tip (point) of the leaf on tulip tree and Magnolia grandiflora hosts. Yellow poplar weevil larvae are white, legless, and approximately 2 mm long. Up to 9 larvae have been recorded in a single blotch mine (Burns, 1971, notes up to 19 larvae are possible). Larvae are mostly observed in late May and June. Pupation occurs in the leaf mines within fuzzy, brown, spherical cocoons and adults of the new generation emerge to feed on leaves. Adults have been observed feeding as late as August in the southern portions of its range in the US (ex. Mississippi), however it is typical for them to be difficult to find following July. Adult weevils may seek indoor shelters (such as homes) for overwintering protection (Johnson and Lyon, 1991).
Feeding damage from this insect is not often reported as of economic importance, however in the southern parts of its range outbreaks have occasionally occurred (Johnson and Lyon, 1991). Adult feeding creates irregularly shaped holes on host plant leaves. Larvae create blotch-type leaf mines within host plant leaves, often at the leaf tip. Mined leaves may turn brown throughout the tree canopy. During outbreak years, it is possible that these insects cause defoliation of entire trees. If terminal buds are damaged, young trees may become deformed. During these outbreaks, weakened trees may be more susceptible to other stressors.
Visually monitor for leaf mines beginning in May. Adult feeding may cause irregular holes to form in host plant leaves sooner than the mines appear (late April to early May). Adult feeding in June may increase the severity of damage observed.
Effective cultural management options are not known at this time.
Natural enemies of the yellow poplar weevil have been reported, particularly hymenopteran parasitoids. Five species (Heterolaccus hunteri, Habrocytus piercei, Horismenus fraternus, Zagrammosoma multilineatum, and Scambus hispae) have been reported to kill 50% of yellow poplar weevil pupae (Burns and Gibson, 1968). Abiotic factors, such as frosts in the late spring, may kill adults and larvae. On the rare occurrence that outbreaks of this insect happen, buildup of natural enemies in the population is assumed to help reduce their numbers below noticeable levels.
Abamectin (NL)
Acephate (NL)
Acetamiprid (L)
Azadirachtin (NL)
Bifenthrin (NL)
Chlorpyrifos (N)
Clothianidin (NL)
Cyantraniliprole (NL)
Dinotefuran (NL)
Emamectin benzoate (L)
Flonicamid+cyclaniliprole (N)
Gamma-cyhalothrin (adults) (L)
Horticultural oil (L)
Imidacloprid (L)
Lambda-cyhalothrin (adults) (L)
Neem oil (NL)
Permethrin (L)
Pyrethrin+sulfur (NL)
Spinosad (NL)
Active ingredients that may be applied systemically include: Abamectin (injection), acephate (injection), acetamiprid (injection), azadirachtin (injection, soil drench), clothianidin (soil drench), cyantraniliprole (soil drench, soil injection), dinotefuran (soil drench), emamectin benzoate (injection), imidacloprid (soil drench), and neem oil (soil drench).
When used in a nursery setting, chlorpyrifos is for quarantine use only.
Make insecticide applications after bloom to protect pollinators. Applications at times of the day and temperatures when pollinators are less likely to be active can also reduce the risk of impacting their populations.
Note: Beginning July 1, 2022, neonicotinoid insecticides are classified as state restricted use for use on tree and shrub insect pests in Massachusetts. For more information, visit the MA Department of Agricultural Resources Pesticide Program.