What Is Wrong With My Boysenberries?

Do the canes and leaves have spots?

Do the spots have light brown to tan centers?

Did the bright orange pustules appeared on the undersides of the leaves in the spring?

Have the unripened berries became dry and crumbly?

Have the fruits fail to ripen or have they stayed red and sour?

Are the leaves curled and yellow?

Does your spirea have leaves rolled into tubes?

Are the leaves covered in coarse stippling and may appear silvery?

Are the leaves yellow, and the plant looks stunted?

Do the canes have wartlike or corky swellings on them?

These symptoms could indicate two fungal diseases - Anthracnose and Septoria Cane and Leaf Spot. These diseases are causing problems mostly in cool and wet springs. In severe cases, twigs can die back and defoliation can occur. All diseased leaves and canes should be pruned off, gathered, and disposed of. Cut canes several inches below the damaged area. Early in the season, spray with lime-sulfur.

Leaf and cane rust disease cause small yellow pustules on boysenberries leaves and canes. All diseased leaves and canes should be pruned off, gathered, and disposed of. Cut canes several inches below the damaged area. Early in the season, spray with lime-sulfur.

Bright orange pustules on the undersides of the leaves indicate a fungal disease - Orange rust. This disease is incurable and can't be controlled by sprays. Diseased plants never recover but the disease can be transferred fast, so dig up and destroy all infected plants as soon as you notice them. Avoid planting boysenberries in proximity to wild blackberries as they can carry orange rust.

There are two diseases commonly known as dryberry disease in boysenberries. The first is common downy mildew, caused by the fungus Peronospera sparsa. The second is also a fungal disease caused by the pathogen Rhizoctonia rubi. Both diseases cause berries to suddenly shrivel up and dry out. Canes may also display necrotic spots. Infected plants should be dug up and destroyed.

If the fruit fails to ripen or have stayed red and sour most likely cause is insect - Redbery mite. These microscopic insects can be controlled with the application of lime-sulfur spray once in early spring when new shoots are 1 inch long, and the second time after the canes have had 1 inch of new growth.

Distorted, curled leaves are caused by aphids. These tiny insects cluster under leaves and on growing tips where they feed on plant sap. Leaves, stems, and buds get distorted, and later leaves and flowers drop from the plant. You can control them by washing them off the plant with water spray. Insecticidal soap should be used with severe infestations.

Rolled leaves are caused by leafrollers. These green caterpillars with brown heads feed on the enclosed leaves and buds. If the infestation isn't severe, handpick the rolled leaves with caterpillars. Spray more heavily infested plants with light horticultural oil according to the directions of the label to smother the insects and any eggs.

These symptoms indicate thrips. Thrips are tiny, yellow to black flying insects. They hide under the leaves. Severely infected plant parts should be removed and destroyed. Control thrips by introducing lady beetles or lacewings, their natural predators. Insecticidal soap helps in severe infestations.

Yellow leaves and stunted look are caused by whiteflies. These tiny, mothlike flies and their larvae feed by sucking plant juices. Whiteflies secrete honeydew, a sugary substance that makes leaves sticky to the touch. Control whiteflies by eliminating garden weeds and by introducing green lacewings in the garden. Spray infested plants with insecticidal soap every 3 days for 2 weeks.

Most likely cause for this is a bacterial disease - Crown gall. This disease can't be cured so remove and destroy all diseased plants, including their roots. You can prevent crown gall by maintaining good soil drainage.

Cane borers often cause boysenberries canes to die. These pinkish, up to 2 inches long larvae enter the cane on the top and tunnel down. In fall, remove dry leaves as they might carry borer eggs and destroy badly infected plants in spring. In spring you can also dust the base of the plants with pyrethrin to kill emerging larvae.