Saperda perforata (Pallas)

Coleoptera: Cerambycidae

IDENTIFICATION

Adults are yellow or grayish, slightly flattened dorsally and are 12 to 20 mm long.^{23, 25, 121, 128} The pronotum typically has a single median spot as well as 8 black spots arranged into two transverse lines.^{23, 25} Each elytron has a stripe of black pubescence along the shoulder, which extends towards the midpoint.^{23, 25} Each elytron also has 5 black spots in a longitudinal line and a black spot on the basal quarter.^{23, 25} Gray antennae have black apices.²

HOST TREES

Populus (main host) and Salix.^{23, 25, 85, 121, 128}

LOCATION OF INFESTATION WITHIN THE TREE

Larvae feed on the inner bark and sapwood of stems and branches.^{23, 25} Immature beetles maturation feed on leaves and thin shoots.^{23, 25}

HOST CONDITION

Weakened, dying, recently felled or stressed trees.^{23, 25, 121, 128} This beetle requires a very moist breeding substrate.¹²¹ Larger diameter trees (18 to 35 cm in diameter) are preferred.^{23, 25}

DISTRIBUTION

Europe and northern Asia.^{2, 23, 25, 128}

SIGNS AND SYMPTOMS

Immature beetles feed on the tissues of green leaves and thin shoots.^{23, 25} Prior to oviposition, females gnaw small 3 mm incisions on the stem or branch and lay a single egg under the bark.^{2, 23, 25} Larvae excavate irregular galleries in the inner bark that are packed with coarse fibrous frass.^{2, 23, 25, 128}

Last instar larvae bore a 22 mm long horizontal gallery into the sapwood and then mine a longitudinal pupal chamber 21 to 27 mm long and 5 to 10 mm wide.^{2, 25, 128} Larvae plug the pupal chambers with fibrous frass and pupate with their heads toward the entrance hole.^{2, 25} Occasionally pupation takes place deeper in the sapwood due to desiccation of the outer sapwood.¹²⁸ Adults emerge through circular exit holes (6 mm in diameter).^{2, 23}

A - Yellow and gray S. perforata. Note 5 black spots on each elytron.

B - Adult S. perforata (yellow morph).

C - Adult S. perforata (gray morph).

D - S. perforata in pupal chamber. Note fibrous frass plug.

E - Adult S. perforata (12-20 mm long).

Photo credits

• A Michael Hoskovec, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic
• B Marcel and Alain Galant
• C Marcel and Alain Galant
• D Till Tolasch, www.koleopterologie.de  
• E Michael Hoskovec, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic