Maple Petiole Borer – Caulocampus acericaulis

Maple Petiole Borer (Caulocampus acericaulis)

Latin Name: Caulocampus acericaulis

Common Name: Maple Petiole Borer


The maple petiole borer (Caulocampus acericaulis) is a sawfly-like non-stinging wasp. The maple petiole borer (also known as the sawfly wasp) is a little wasp-like sawfly that is seldom noticed due to its small size. This insect attacks various maple species, but Sugar Maple is the most common.

  • Adult borers are pretty unusual to come across. They are little, around 1/4 inch long, with a black head, thorax, and a pale abdomen.
  • Larvae are cream-colored with reddish heads, legless, and about 1/3 inch long when grown-up.

Host plant: Sugar Maple

Territory: It is a European native introduced to North America.

Damages Caused by Maple Petiole Borer:

Maple petiole borers do not affect the tree’s health or appearance.

  • Individual leaves drop to the ground with a portion of the stem still attached.
  • The leaves are still green, and the tips of the leaf stalks are typically black.
  • They’re usually found in minor amounts. Only approximately 10% of the leaves have been impacted. This amount of defoliation is easily tolerated by trees.

Description about Leafminers:

Leafminer adults are tiny flies with yellow areas on their thorax, legs, and abdomen. They are 0.1 inches (2.5 mm) long, black to blue, and have yellow portions on their thorax, legs, and stomach. There is frequently a visible yellow patch towards the base of the wings. The white eggs are hidden behind the leaf’s epidermis and hatch in 4 to 6 days. Maggot larvae are typically buried between leaf surfaces in the mines where they feed; they range in color from yellow to white, are 0.25 to 0.33 inches long, flat at the back end and pointed in front, and are 0.25 to 0.33 inches long, blunt at the back end and pointed in front. Pupation is carried out underground or in mines. During the summer, the life cycle lasts around 23 days

Life history and Habits:

Maple petiole borers spend the winter in the soil as pupae before emerging as adults in the spring. After mating, the female punctures the petioles with her ovipositor and lays a single egg near the leaf blades. The larvae are whitish and smooth, brownish heads and have a weevil-like appearance due to the short abdominal legs. Larvae are around 1 cm long when fully mature. Larvae burrow down 5-8 cm into the earth to overwinter after hatching. The petioles break quickly, and the injured leaves fall to the ground. Mature larvae pupate in the spring and emerge as adults in early to mid-April. Every year, a new generation is born.