Raspberries are generally straightforward to grow in your home garden, but they’re sometimes prone to a few pest and disease issues. In this article, discover practical solutions for some of the most prevalent raspberry problems.
Plants are significantly more resilient against attacks from insects and pathogens when they are healthy. As such, giving your raspberry plants appropriate amounts of light, nutrients, and water is their best line of defense.
Utilize cultural controls to prevent pest and disease problems in your garden when possible. Companion planting and crop rotation are incredibly effective ways to reduce the likelihood of difficulties with plant disease and insect pests arising in the first place.
Practical Solutions for Prevalent Raspberry Problems
When complications crop up in your garden, always try natural remedies first before using harsh chemicals. Read on to find out what to do if your raspberry plants aren’t producing fruit or start showing signs of distress after you are finished transplanting raspberry bushes or have had them in the garden for a while.
Understanding how raspberries grow is essential to provide proper care. After you learn when to plant raspberries to take advantage of ideal growing conditions, plant raspberry seeds or seedlings where they get full sun and have rich, well-draining soil. Raspberry brambles become challenging to maintain without consistent pruning.
Floricanes, or summer-bearing raspberries, develop fruit on second year canes. Everbearing raspberries, or primocanes, produce fruit on new growth in late summer.
Learn the proper way to trim raspberry bushes to prevent disease and increase fruit yields. Prune primocanes to ground level each year and prune only the old canes that already fruited on floricane raspberries.
One of the first signs of plant distress when growing raspberries is the raspberry leaves turning brown or yellow. Leaf discoloration may indicate several different problems, so it’s crucial to take note of other symptoms, too.
Remember that insecticides also affect beneficial pollinators and predatory insects. Are red raspberries and black raspberries the same regarding bugs? Yes, be mindful about spraying your raspberries, and only target severe infestations.
Bacterial Raspberry Disease
Raspberry canes sometimes get attacked by harmful bacteria that cause previously healthy canes to turn brown and stop producing fruit. The most prevalent bacterial raspberry disease problems are bacterial blight and fire blight.
Both diseases lead to dark patches that appear burned on the raspberry canes and leaves. There is no difference between black raspberries vs blackberries when it comes to blight. The bacteria thrive in damp conditions and overwinter in old wood.
According to the Minnesota State University Horticulture Extension, treating plants with a copper fungicide in early spring helps prevent bacterial blight. Spray the entire plant two or three times at seven to ten-day intervals before the leaves emerge in early spring.
Unfortunately, there’s no cure for fire blight. Remove infected plants by cutting the canes to ground level. Burn or throw them in the garbage. Avoid composting infected plant material.
Fungal Diseases that Affect Raspberries
Fungal diseases often spread between plants through water droplets. Provide adequate air circulation, and use drip irrigation or a soaker hose to keep the leaves dry when watering.
Raspberries’ most common fungal diseases include anthracnose, cane blight, powdery mildew, and spur blight. Treat affected plants using organic fungicides with copper or sulfur.
In addition, remove the affected canes and dispose of them appropriately, as fungal spores easily overwinter and return in the spring.
Anthracnose infects the bark and wood, leading to white or beige cankers on sections of the cane between leaf nodes. The edges may turn purple.
Cane blight occurs when wounds on raspberry canes become infected. Reddish-brown streaks expand outwards, eventually making the entire cane die back.
Powdery mildew appears as a white, fuzzy coating on raspberry leaves, fruit, and canes. The spores first develop on the leaves’ undersides, generating light green or yellow blotches on the leaf surface.
Spur blight emerges at leaf nodes on raspberry canes. You’ll notice your raspberry bush leaves turning yellow first, then progressing to brown or black before falling off. Purple or brown lesions form on the stems.
Verticillium wilt and phytophthora root rot result from soil-borne fungi. Unfortunately, there’s no cure for verticillium wilt other than removing the infected plants.
Spores persist in garden soil for many years, so avoid growing susceptible plants in that area. Treat phytophthora root rot with a hydrogen peroxide soil drench.
In a clean bucket or watering can, combine one part hydrogen peroxide with three parts water. Mix thoroughly, then pour it around the base of your raspberry plants.
Wait several days before watering to allow the root system to absorb the peroxide. Repeat two or three times over two weeks.
Flying Raspberry Bugs
We aren’t the only ones who find raspberries delicious. Some of the most widespread raspberry bugs include aphids and raspberry cane borers.
Aphids feed on sap from raspberry leaves and cause problems like leaf curl and yellowing. Spray affected canes with an organic pesticide like neem oil or insecticidal soap or make your own homemade plant bug spray. Sometimes, the best natural aphid spray for plants is a steady stream of water from the hose to dislodge the critters.
Cane borers are beetle larvae that burrow into new canes and overwinter in the plant’s crown. In early spring, they emerge as adults and lay eggs on the tender new shoots. You’ll notice wilting or blackened cane tips and significantly diminished fruit production.
Eliminate cane borers by removing the infested canes where larvae spend most of their first year of life. When females lay eggs, they chew two rings or girdles in the fruiting canes and lay an egg between them.
Prune the cane several inches below the lowest girdle and bury the remaining portion. Burn the infested canes.
Soil-Borne Pests that Damage Raspberry Plants
Nematodes are tiny soil-dwelling worms. While most nematodes are harmless, and some are even beneficial, several types generate problems for raspberry plants.
Lesion nematodes are the most prevalent. They cause lesions on the roots, wilted and yellowing leaves, stunted growth, and poor fruit production. This damage inhibits nutrient and water uptake and provides entry points for pathogens.
The effectiveness of insecticides is limited, so nematode populations are best controlled by encouraging their predators and keeping your plants healthy. Add organic compost to your garden soil each year to encourage soil microbes and use mulch to suppress weeds.
Whether you’re growing red raspberries (Rubus idaeus) or black raspberry (Rubus occidentalis), it’s critical to familiarize yourself with their most common pest and disease problems so you can plan when to harvest raspberries to enjoy their juicy taste in your favorite recipes.
Closely monitor your plants throughout the growing season for signs of distress. If you notice your raspberry leaves turning brown, look closer to find out if you’re dealing with raspberry bugs or a type of raspberry disease.
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