HomeRaspberriesRaspberries: Fruits is small, deformed, or crumbly

Raspberries: Fruits is small, deformed, or crumbly

Crumbly, small, misshapen fruit can have several causes, including

Tarnished Plant Bugs (Lygus lineolaris) feed on flowers and developing fruit and are a common cause for crumbly, misshapen fruit

Unripe raspberry with an insect sitting on drupelets. Insect resembles a stinkbug nymph, with an obovoid body attached to a triangular head. Insect is mostly green, but has two black sections on its back where wings might be. Insect has small, black, circular eyes. Insect is the size of 3 raspberry drupelets.
Tarnished plant bug (Lygus lineolaris) nymph on unripe raspberry.

 

Ripe raspberry with an insect sitting on drupelets. Insect is mostly brown, with a trapezoid-shaped body. The abdomen has three golden-yellow triangle-shaped marks, two near the base of the wings, and one at the junction of the thorax and the abdomen. Insect has a small head and L-shaped brown antenna.
Tarnished plant bug (Lygus lineolaris) adult on raspberry.

 

Five raspberry fruit, with stem attached, in varying stages of ripeness on black background. Riper fruit have brown discoloration on the drupelet surface, and discoloration is most prominent at the fruit tip. White fruit has greenish scarring on drupelet surface. Green fruit have brown discoloration scattered randomly across drupelets.
Tarnished plant bug damage on raspberry.

More tarnished plant bug information

Raspberry Bushy Dwarf Virus also causes crumbly berries. A lab test is required to determine if this virus is present in a planting. Once infected, a planting will always be infected. More raspberry virus information

Tomato ringspot virus is common in older red raspberry plantings and also causes fruit to crumble when harvested.

Three raspberry fruit held up in hand. Fruit appear halfway-ripe. Many drupelets are misshapen and under-developed.
Tomato ringspot virus symptoms in raspberry fruit. Photo courtesy of Kevin Schooley, National Clean Plant Network.

More raspberry virus information

Poor pollination and very low humidity during pollination can cause crumbly fruit. Symptoms generally do not recur the following year. More raspberry pollination information

Three blackberries lined up on paper towel. Blackberries have larger drupelets irregularly distributed on the outer edges of the fruit, and large clusters of small drupelets. Small drupelets are one-third of the size of the large drupelets.
Blackberry with inadequate drupelet development as a result of poor pollination.

Heat stress can be a cause of deformed fruit in many crops.

Circle of berries on paper towel. Black raspberries, red raspberries, and blackberries are all malformed. Berries appear duplicated and merged. In the center of the circle, there is a receptacle with two points showing how even the receptacle is doubled and malformed.
Heat stress can cause double fruit in many bramble berries.

Frost damage is another cause of deformed fruit and reduced yields. Flowers damaged by frost will develop poorly, or not at all.

Blackberry branch with open flower buds. Center of every bud is black. Branch looks otherwise healthy and green.
Frost damaged flowers in blackberry. Note the black, necrotic tissue. Photo courtesy of Kathleen Demchak, PSU.