Raspberries: Floricanes are wilting on the upper portion of the cane, but the lower portion is unaffected

Wilting of the upper parts of canes with lower parts unaffected may result from different causes that are for the most part readily distinguishable. These include:

Flat-headed Cane Borers
Tree Crickets
Cane Blight

Flat-headed Cane Borers such as the Rednecked Cane Borer or Bronze Cane Borer do not girdle canes as does the Raspberry Cane Borer. Adults of both insects feed along leaf edges. Females insert eggs into young canes. Borer larva, or grubs, hatch and tunnel inside the cane while feeding. This causes a symmetrical gall or swelling to form.

Close-up of raspberry stem with vertical strips of damaged tissue, where the stem appears to have cracked from being stretched internally. Below the area with strips of damage, there is a spherical hole the size of a large pinhead. — Flat-headed cane borer *(Agrilus rubicola or A. ruficollis)* tunnel entrance and cane damage.

Canes are weakened, wilting above the swelling, and sometimes breaking off.

Raspberry cane with girdling from multiple horizontal lines. The outer surface of the cane is split and cracked, as if it became swollen and the skin split. Cane is torn off above the girdle marks.

Yellowing of upper portion of fruiting cane; lower portion of cane remains unaffected.

Raspberry cane with one ripe raspberry at tip. Leaves on stem are lighter in color than on neighboring canes. Some leaves are bronzed at edges. Leaves at base of cane are healthy and dark green.

Removal of leaves reveals borer swelling.

Raspberry cane with stripped leaves revealing a pale green stem with an irregular, elongated patch of purple-red stem. The discolored section is slightly swollen and curves along the cane, being approximately 3-4 inches in length. — Flat-headed cane borers, such as Agrilus ruficollis and Agrilus cuprescens, cause a discolored swelling on raspberry canes.

Beetle on leaf. Beetle has elongated black abdomen with vertical ridges. Beetle head is rust-colored with a flattened front. Beetle is approximately as long as one penny, but more narrow in shape. — The Rednecked Cane Borer (Agrilus ruficollis) adult.

Close-up of raspberry cane with small, straight, greenish-yellow larva on lower portion of cane. Larva is marked by faint horizontal stripes that split the body into numerous segments, and a small dark head with no antenna. Raspberry cane has old and fresh vertical splits and cracks along the surface. Old cracks are browned and marked with scar tissue. New crack is wider and does not yet have brown tissue surrounding the damage. — Exposed redneck cane borer (*Agrilus ruficollis*) larva visible below cane swelling.

More Raspberry Cane Borer (Girdler) and Rednecked Cane Borer information
Integrative Pest Management of Raspberry Cane Borers (University of Connecticut)

Tree Crickets

Insect on leaf. Insect has translucent, obovate wings and a pale green, narrow, triangle-shaped body. The head is circular with a slight taper at the mouth. The head has one rust-colored, diamond-shaped mark in its center. Insect has long, straight antennae as long as its body. Insect has powerful hind legs and two sets of thinner legs. Legs are held at 45-degree angle by prominent, elbow-like joint. — Adult snowy tree cricket (*Oecanthus fultoni*).

Tree crickets of several species lay eggs in canes, often causing the portion above the eggs to die. Oecanthus fultoni, the Snowy Tree Cricket, is the most common in causing damage to raspberries in the Northeastern US and Canada.

Raspberry cane cut in half vertically. Halves are arranged to display the bark-side and the inner-wood side of the same branch. The inner-wood side has 18 straight penetrations that travel across the bark and into the central pith. The penetrations lead to small, yellowish larva that are dwelling inside of the inner wood. The bark-side of the wood has a vertical stripe of cracked and crumbly bark that appears to be marked with little holes. — Snowy tree cricket (*Oecanthus fultoni)* oviposition damage in raspberry cane.

More tree cricket information

Cane Blight, a fungal disease, can infect canes and girdle them, causing the upper portion of the canes to die.

Raspberry cane with shriveled, dried leaves that are still green in color. Skin of cane is cracked and peeling outwards in curls. — Cane blight (Leptosphaeria coniothyrium, also called Kalmusia coniothyrium)on raspberry.

More cane blight information