Raspberry Crown Borer

Updated 21 March 2024

Raspberry Crown Borer, Pennisetia marginata (Harris)

I. Introduction: The sesiid moth can be a severe pest to raspberry and blackberry plantings. Adult moths are yellowjacket mimics. All stages occur on red raspberry, Rubus idaeus L., black raspberry, R. occidentalis L., himalaya blackberry, R. procerus Muell., cutleaf blackberry, R. lacineatus Willd., loganberry, R. loganobaccus Bailey, boysenberry, R. sp. cult., thimbleberry, R. parviflorus Nutt., and salmonberry, R. spectabilis Pursh.

II. Biology: Eggs are laid on the undersides of new leaves, with 2-3 eggs per plant. Eggs incubate 3-10 weeks, beginning to hatch in late July (about the first week of September and continuing until early November in the northern part of its range (Canada)). The young larva spins down to the crown, where it overwinters in a hibernaculum. In the spring it tunnels into the cambium. Cracks develop at this site, from which reddish brown frass is produced in April. During the first summer, the larva feeds at the base of new canes, girdling the plant and causing gall formation. Galls are most evident in October. There is two-year life cycle. In the second summer, the larva ascends into a cane, girdling it a few inches above the soil surface, and causing it to wilt and break. The pupal stage occurs in late June to early August. Moths fly from early to mid July through late September (August through September in the north). Females begin to oviposit beginning on the first day after emergence; the female lives 3-11 days, averaging about 103 eggs.

The following graph shows raspberry crown borer trap captures in experimental traps containing four pheromone loading rates, placed in Westmoreland County in 1997. Males were already flying on the first sampling date (17 July), and were last captured on 26 September. The peak of activity was on 2 August.

IV. Control: Chemical control: Thiamethoxam (Actara) or Bifenthrin (Brigade 10WSB), may be used as a drench treatment for raspberry crown borer. Apply at either post-harvest (fall) or pre-bloom (spring), as a drench application directed at the crown of plants in a minimum of 50 gal water/A.  Do not make a prebloom foliar and prebloom drench application.  The most effective time of application is between October and early April.

The following links may be used for chemical control recommendations:
Pest Management Guide for Commercial Small Fruit (html)
Pest Management Guide for Home Fruit (html)

Biological control: Entomopathogenic nematodes are also available for the control of raspberry crown borer.

Cultural control: Remove all wilted canes in June and July.

V. Other information: See also Arkansas page on raspberry crown borer, and WSU Site for additional information.

Virginia Small Fruits Page Fruit Loop Homepage

Maintained by: Douglas G. Pfeiffer
Department of Entomology
Virginia Tech