Raspberry Plant Viruses and Bugs

Mosaic

• Mosaic is the most damaging viral disease afflicting raspberry plants. Symptoms include leaf mottling, puckering and blistering. These symptoms may disappear in the summer, but the disease remains. Yield is reduced and berry quality is poor. Aphids spread raspberry mosaic. Inspect your plants often for aphid infestations and treat them with an insecticide approved for use on food crops.

Leaf Curl

• Plants infected with leaf curl virus have small, crinkled, dark-green leaves that curl down and inward. Infected plants die within 2 or 3 years. There is no control, so remove and destroy plants as soon as the disease is found. Aphids spread leaf curl, so insect control is necessary.

Tomato Ringspot

• Tomato ringspot virus affects only red raspberries, not the black varieties. Infected plants are less vigorous than normal but otherwise appear fine. The virus causes berries to be small and crumbly. The dagger nematode spreads this soilborne virus. Test the soil for nematode infestation before planting raspberries.

Raspberry Streak

• Tobacco streak virus causes Raspberry streak and affects only black raspberries, not red. Purple streaks appear on the lower parts of canes and lower leaves are yellowed and mottled. Leaves near the cane tips are hooked or twisted and often darker green than usual. The fruit on infected canes is small and flavorless. Pull and destroy badly infected plants.

Cane Insects

• Two types of cane borers, beetles that lay their eggs inside the raspberry canes after puncturing it, infest raspberries. The raspberry cane maggot is a small fly that lays its eggs on new buds or cane tips. For all three insects, the canes swell or wilt. Cut off the cane 6 inches below the affected areas and apply insecticide in the spring.

Crown Borers

• The raspberry crown borer, a clear-winged moth, has a 2-year lifecycle. This insect overwinters in the roots and bark below soil level the first winter but spends its second winter in the crown, causing canes to wilt. Dig up and destroy badly infected plants, but light infestations can be controlled by 2 years of spring-and-fall permethrin applications.

Other Pests

• Aphids feed on new growth. They can spread several viral diseases. Control them with a strong stream of water or insecticides. Raspberry fruitworms are beetle. They feed on raspberry foliage and damage the fruit. Pick off the worms by hand or spray with permethrin. The picnic or sap beetle is attracted to overripe and damaged fruit. Frequent picking of ripe fruit is the best control. Japanese beetles leave holes and ragged edges on the foliage. Hand pick them or spray with an insecticide.