Raspberries: Only floricanes are wilting while primocanes appear healthy

Causes of this type of damage include:

Winter Injury – damages floricanes but not primocanes. Varietal differences are apparent. Often injury occurs in March when temperatures fluctuate, rather than in mid-winter. Occasionally, winter injury is not apparent until fruiting laterals begin to grow. With the onset of warm temperatures, the injured vascular connections cannot supply the laterals with water, so the laterals collapse.

Raspberry planting with combination of healthy, leafed-out canes and defoliated, bare canes.

Raspberry planting with healthy leaves on lower sections of canes. Upper halves of canes either have yellow foliage, or are entirely bare.

High Winds – can break floricanes at their base, causing them to wilt and die. Usually affected canes can be pulled from the crown with a quick jerk.

Crown Borers – damage floricanes at their base, causing them to wilt and die. Entire plants may be killed.

Raspberry planting with single dead raspberry plant. Dead plant is devoid of leaves.
Photo courtesy D. Johnson, University of Arkansas

Look for burrows at the base of canes and in the crown and roots.

Close up of root base of dug-up raspberry plant. There is no bark 2-3 cm above the root zone, and a small hole the size of a large pinhead is visible in the base of the stem.
Photo courtesy D. Johnson, University of Arkansas

Adult crown borers are clear-winged moths that resemble yellow jackets. They emerge from July to September.

Wasp-like insect on leaf, viewed from above. Insect is black with thin horizontal yellow stripes and yellow legs. Head and antenna are black.
Adult crown borer.

Photo courtesy D. Johnson, University of Arkansas

Crown borer eggs are laid singly on the undersides of leaves.

Dry raspberry leaf with multiple shiny brown eggs shaped like sesame seeds.
Crown borer eggs on leaf underside.

Photo courtesy D. Johnson, University of Arkansas

Larvae burrow down individual canes into the crown. A single larva may kill several canes on one plant.

Raspberry cane cut in half longitudinally. The exposed pith of the cane is marked by several brown, vertical stripes that look like larval tunnels.
Photo courtesy D. Johnson, University of Arkansas

Dark red pupal skins attached to the lower section of canes/crown are also a characteristic sign of crown borer infestation.

Dug-up raspberry plant with an inchlong, brick red pupal skin attached near the junction of roots and stem. The pupal skin is mostly intact and tube-shaped.
Red pupal skin of a crown borer on raspberry.

Photo courtesy D. Johnson, University of Arkansas

More crown borer information

Rodent damage – In this case, rabbits stripped the bark from canes of these black raspberries during winter, girdling them.

Branches of dormant raspberry plant with white, inch-long markings on canes. Markings are approximately one inch apart and are circular to oval in shape.
Rabbit damage on black raspberry

Similar rabbit damage on thornless blackberries.

Close-up of base of blackberry plant with multiple canes. At junction with ground, canes are stripped of skin entirely. Moving up the cane, there are circular marks where skin is bitten off.
Rabbit damage on base of blackberry.