If you’ve ever tasted a juicy raspberry straight from the vine, you know there’s nothing quite like it. As gardeners, we want to protect that little piece of paradise by keeping our raspberry plants healthy. This means learning how to identify and treat pests and diseases that can harm our plants.
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Raspberry leaves are delicate and susceptible to damage from various pests. As a raspberry grower, seeing ragged, chewed or mined leaves on your plants can be concerning. However, don’t panic! With some detective work, you can identify the culprit and take steps to protect your raspberries.
Common Raspberry Leaf Pests
Several insects are attracted to the tender foliage of raspberry plants Here are some of the main offenders to look out for
Japanese Beetles
Japanese beetles are a very common pest of raspberries in most regions. The adult beetles are metallic green and copper colored, around 1⁄2 inch long, and tend to congregate in large numbers on leaves which they voraciously devour. This leaves behind characteristic skeletonized or lacy looking leaves with just the veins remaining.
Raspberry Fruitworms
The raspberry fruitworm is a small green beetle that feeds on leaves and other tender plant tissues. Adults nibble holes between the leaf veins, while the larvae bore into buds and fruits. Close inspection will reveal the adult beetles and larvae, as well as the tell-tale round holes in developing leaves.
Raspberry Sawflies
Sawfly larvae look like caterpillars but are actually the young of a primitive wasp species. The larvae of the raspberry sawfly feed on leaf edges and can completely defoliate canes if infestations are heavy. Look for yellowish green larvae up to 3⁄4 inch long on damaged leaves.
Leafminers
These tiny flies lay eggs inside of leaves. The larvae then feed and develop between the upper and lower leaf surfaces, creating meandering tunnels or ‘mines’. Damaged leaves will appear dried or brownish when held up to the light. Different leafminer species target specific plants so infestations usually indicate the presence of raspberry-specific leafminers.
When Do They Feed?
Timing and weather patterns influence when each pest is active:
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Japanese beetles emerge as early as late May and are active through summer into fall. They are especially problematic during hot, dry midsummer weather.
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Raspberry fruitworms do the most damage in spring and early summer as adults feed on new leaves and larvae bore into fruit. Monitor for them starting from budbreak onward.
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Raspberry sawfly larvae appear in spring soon after the first leaves emerge. They feed for 4-6 weeks before dropping to the soil to pupate.
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Leafminers produce 2-4 generations per year starting in early summer. Populations peak in midsummer but damage can appear anytime between May and October.
Preventing Raspberry Leaf Damage
While some nibbling is inevitable, you can reduce serious defoliation with integrated pest management:
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Encourage natural predators like birds, beneficial insects, spiders etc. Avoid broad-spectrum insecticides which kill these allies.
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Use row covers as a physical barrier to insects in spring and early summer when leaves are most vulnerable.
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Hand pick Japanese beetles and larvae of other pests to reduce populations.
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Apply insecticidal soaps or oils to suffocate soft-bodied insects like sawfly larvae. Avoid pollinator-toxic neonicotinoids.
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Use pheromone traps to capture adult pests like raspberry fruitworms before they can breed and lay eggs.
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Improve plant vigor with regular watering and pruning. Healthy canes can better withstand some leaf loss.
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Clean up thoroughly after harvest. Remove old canes and debris where insects can overwinter.
When to Worry
Minor leaf damage is no cause for concern. But if pests defoliate entire canes or damage is severe over multiple seasons, yields may drop. Seek expert help to identify the exact pest and consider stronger chemical control if required. Always follow label directions exactly.
With some basic monitoring and prevention, you can keep most leaf pests in check. And if you do see leaves getting eaten, use the clues above to identify which culprit is munching on your raspberries so you can take targeted action to stop them. Vigilance and quick response will help ensure your plants can keep growing and producing berries.
Look for Visual Clues
Here are some things to look for that can help you figure out what’s going on with your raspberries:
- Feeding patterns: Different pests eat in different ways. Holes in leaves or berries could mean you have a pest problem, while a sticky substance on the plant might mean aphids have moved in.
- Discoloration: This can be one of the first signs that something is wrong. Leaves turning yellow could be a sign of not enough nutrients or a disease.
- Distortion: If your plants’ leaves or berries look misshapen or weird, it could be because of bugs or a disease.
- Seeing bugs: Some pests, like Japanese beetles and aphids, are easy to spot without any special tools.
The more often you check your plants, the quicker you’ll catch any problems that arise. Aim to look at your raspberry plants once a week, especially during the times when they’re growing the most. Take a close look under leaves, along the stems, and near the soil. Remember, finding an issue early is half the battle!
Tips for Identifying Raspberry Plant Pests & Diseases
Gardening is like being a detective when it comes to finding out what’s wrong with your raspberry plants. The sooner you find a problem and figure out what it is, the better chance you have of saving your plants.
Benefits of Raspberry Leaves
FAQ
How do I keep bugs from eating my raspberry leaves?
Placing insect netting (floating row covers) over your garden is the best way to prevent leaf-footed bugs from attacking your plants. Diatomaceous earth can also be laid down around your garden to help get rid of them.
What’s eating holes in my raspberry leaves?
Some common culprits include: Pests: Such as raspberry beetles, spider mites, and aphids that eat leaves and fruit. Diseases: Like botrytis fruit rot and powdery mildew that spread quickly under the right conditions.
What animal eats raspberry leaves?
Raspberry leaves are a favorite food of Japanese beetles. Japanese beetles on raspberry bush. Photo courtesy of Heather Faubert, URI Extension. Raspberry fruitworm (Byturus unicolor) prefers red and purple raspberries.
How to protect raspberry plants from animals?