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Raspberry Crown Borer - Pennisetia marginata
  
HOSTS:
All rubus
species including raspberry. DESCRIPTION:
Adults
are clear winged moths which resemble a yellow jacket: black body with
four yellow transverse stripes. Larvae are small and white with a light
brown head. Eggs are reddish brown. LIFE
CYCLE: Eggs are
laid on the underside of leaflets in late summer. After hatching the
larvae migrate to base of canes to begin their 2nd year below the soil
level at the base of the stem. The following spring larvae bore many
tunnels and by the middle of the second summer the crown may be
extensively damaged. In mid-summer of the second year pupation begins
and by late August the clear winged moths appear and mate. After mating
the female lays about 140 eggs and a new cycle begins. CONTROLS:Cultural: Remove alternate hosts (wild rubus species). Prune out and destroy infested canes in the fall. Keep plants properly irrigated and vigorous. Chemical: Insecticides drenched over the crowns in early spring just before bud break may diminish a portion of the larvae. Least-toxic options are pyrethrin / rotenone mixtures. |
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