Skip to main content

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.

raspwinj3-opt

raspwinj2-opt

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 (below).

raspcrborerdamage01-opt
Photo courtesy D. Johnson, University of Arkansas

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

raspcrborerdamage02-opt
Photo courtesy D. Johnson, University of Arkansas

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

raspcrboreradult1-opt
Photo courtesy D. Johnson, University of Arkansas

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

raspcrboreregg-opt
Photo courtesy D. Johnson, University of Arkansas

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

raspcrborerlarva-opt
Photo courtesy D. Johnson, University of Arkansas

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

raspcrborerpupalskin-opt
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 (below) during winter, girdling them.

blkrasprabbit-opt

Similar rabbit damage on thornless blackberries (below).

blkberryrabbit-opt

Skip to toolbar