Prionus borers

Insect

Prionus borers

Prionus laticollis (Drury) Prionus imbricornis (L.)

Coleoptera: Cerambycidae

Distribution: Most fruit-growing states and provinces in eastern North America.

Photos

Larvae feed on root and crown wood which they hollow, girdle or sever.

Larvae feed on root and crown wood which they hollow, girdle or sever. Arthur Agnello, Cornell Univ.
D

Broadnecked root borer, Prionus laticollis (Drury) Tilehorned prionus, Prionus imbricornis (L.) Adults are robust, broad, somewhat flattened blackish to reddish brown beetles with antennae roughly half the length of their bodies (A). Larvae are large, fleshy, elongate grubs, creamy white to yellowish in color, with 3 pairs of small legs, a swelling behind the small head capsule, and strong black mandibles (B).

  • Crops Affected: apples, cherries, peaches, plums

    Damage

    Attack apple, cherry, peach and plum. Larvae of both species feed on the wood of roots and crown, which they hollow, girdle or sever (C, D); the larval stage can last three years or more. Affected trees show a gradual thinning and yellowing of foliage and limb-by-limb mortality. Young trees can be chewed off just below the surface; established trees may have only 1 or 2 roots left intact and can be blown over by wind.

    Management

    Keep base of trees free from weeds to encourage predators; use oviposition barriers of netting or screening on bottom 30–60 cm (12–24") of trunks. A surface deterrent or insecticide can be sprayed on trunks in early summer.

Related Content

About

Resources

Events

  • follow us on youtube
  • follow us on linkedin
Michigan State University
  • Spartans Will.
  • © Michigan State University

MSU is an affirmative-action, equal-opportunity employer, committed to achieving excellence through a diverse workforce and inclusive culture that encourages all people to reach their full potential.

Michigan State University Extension programs and materials are open to all without regard to race, color, national origin, gender, gender identity, religion, age, height, weight, disability, political beliefs, sexual orientation, marital status, family status or veteran status. Issued in furtherance of MSU Extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. Quentin Tyler, Director, MSU Extension, East Lansing, MI 48824. This information is for educational purposes only. Reference to commercial products or trade names does not imply endorsement by MSU Extension or bias against those not mentioned.

The 4-H Name and Emblem have special protections from Congress, protected by code 18 USC 707.

We comply with the Federal Trade Commission 1998 Children’s Online Privacy Protection Act (COPPA).