If you grow any type of food, then you know how frustrating it can be to lose your plants to pests, predation, and pathogens.
Raspberries aren’t immune to any of these issues, and if they aren’t attended to, they can obliterate your entire crop. Let’s take a look at the most common raspberry pests and diseases you may come across and how to deal with them.
Raspberry Pests and Diseases
The insects and animals that prey on raspberries can devastate your crop. Some of them can be fended off with preventative measures, while others need more proactive methods to eliminate them once they’ve shown up.
Let’s talk about one of the most common pests first.
1. Slugs and Snails
Although raspberry bushes aren’t their favorite snacks, slugs and snails will feed on ripe berries and foliage if there are few other food sources available to them.
As such, if you don’t have a lot of other plant species growing on your property just yet, expect to deal with at least a few of these slimy raspberry pests.
They prefer to munch on overripe fruit that has fallen onto soil level but will ooze their way up the canes to reach the ripe berries as well.
Fend them off using your favorite method, or visit our guide to learn a few techniques. If you’re raising ducks or chickens, let them loose in your garden: they love to munch on tasty slugs when the opportunity arises.
2. Spider Mites
If your fruit bushes seem to be covered in a fine, thread-like webbing, you’re likely dealing with spider mites. They pierce plants’ stems and veins and feed off the sap while leaving wispy webs in their wake.
Although they don’t damage the plants much directly, the incisions they create leave the bushes open to infection. They also drain the plant of energy if their populations are large enough.
Since spider mites thrive in hot, dry conditions, blasting your bushes with the hose can make the surroundings too uncomfortable to stick around. They also dislike neem oil immensely.
Plant companions that attract lacewings to keep their populations down, and be sure to snip off and burn any plant parts that are too damaged (or infested) to save.
Learn more about how to get rid of spider mites in our article.
3. Cane Borers
As you may have assumed from their name, cane borer beetles (from the Cerambycidae family) burrow into Rubus canes, where they feed on the cane’s inner tissues.
This prevents the canes from being able to uptake nutrients or water properly, causing them to wilt, stop producing fruit, and die prematurely.
If you notice that your wilty plants have dark tips and there are black or dark brown rings around the canes, those are telltale signs that you have borers.
Use sterilized snips to cut the canes a few inches below the rings, and burn them. Remove all detritus from the area, put down diatomaceous earth, and monitor your plants’ regrowth diligently.
4. Raspberry Fruitworm Beetles
There are few things as disappointing—or disgusting—as harvesting a big handful of raspberries and finding that they’re infested with worms or caterpillars. The larvae of fruitworm beetles (Byturus unicolor) are insidious raspberry pests that can ruin an entire crop before you can blink.
They overwinter in plant detritus, so be sure to clear away fallen leaves and debris in autumn. If you see these wiggly jerks on your plants, use an organic insecticide such as neem to send them on their way.
5. Japanese Beetles
Whereas the beetles mentioned above feed entirely on fruits, these raspberry pests devour your plants’ leaves instead. Japanese beetles (Popillia japonica) consume leaves between their veins and ribs, essentially skeletonizing them.
They skeletonize the leaves by consuming the tissue between the veins, leading to defoliation if present in large numbers.
Diatomaceous earth is effective for reducing their numbers, and you can also wrap sticky tape around the cane stems to catch them before they can reach the tasty leaves they adore.
6. Aphids
Few raspberry pests are as annoying to deal with as aphids (Aphidoidea). They literally suck the life out of your plants by feeding on sap from the stems, leaving them vulnerable to all manner of diseases.
The “honeydew” they excrete can draw ants and other insects that are vectors for various infections such as mosaic viruses or fungal pathogens.
Chickens, Guinea fowl, quail, and ladybugs all feed on aphids, so they can help to keep infestations to a minimum. Remove aphids from plants by blasting them with your hose, and keep them at bay with neem oil and/or diatomaceous earth.
Learn more about how to spot and eliminate aphids in our article.
7. Herbivores
While bunnies, groundhogs, and deer are too cute to really be “pests,” they can certainly wreak havoc on your young raspberry plants. As such, scattering wolf, coyote, fox, or mountain lion poop or urine around the area should keep these animals from annihilating your crop.
Alternatively, you can sow a perimeter of alliums around your bushes to keep these (albeit adorable) raspberry pests away, as well as interplanting them around the canes.
Herbivores have very sensitive noses and can’t stand the scent of garlic or onions. We have a thick wall of garlic chives around all of our bushes, and they seem to fend off interlopers well.
8. Rodents
I can’t tell you how many times I’ve had to chase squirrels away from my raspberry and blackberry bushes. Mice and shrews often snuffle around on ground level to pick up the fallen, overripe berries, and that’s fine, but squirrels tear them right off the bushes and gobble them voraciously.
Much like with deer and rabbits, squirrels will keep away from areas that smell like predators or onion and garlic.
9. Birds
Birds are wonderful for countless reasons, but obliterating your raspberry crop is not one of them. I don’t like to call them “raspberry pests” per se, so much as hungry wild creatures who take whatever opportunity they can get to feed themselves and their young.
You can prevent them from eating all of your raspberries by covering your bushes with fine mesh birdproof netting, as long as you check it daily to ensure that no birds have gotten caught in it.
Another alternative is to grow yellow (aka “golden”) raspberries instead of red, black, or purple varieties. Birds consider white, yellow, and green berries to be “unripe,” so they’ll be less likely to eat yours.
10. Opossums
Although these little weirdos may look unnerving, they’re actually very sweet, gentle animals, so please don’t hurt them. They’re opportunistic feeders and will prey on ripe raspberries when and if the opportunity arises.
They’re also likely to be scared off by predator poop or urine, but you can also simply offer them alternative snacks so they stay away from your berry bushes.
Sweet potatoes, carrots, apples, and mealworms are ideal: simply create a feeding area well away from your raspberries, and they should leave the bushes alone.
11. Raccoons
I hate to call raccoons “raspberry pests” because they’re such cute, clever little monsters, but they can certainly devour your entire crop before you can harvest a handful.
While they may be deterred by predator scents, your best bet is to fence off your berry bushes so they can’t access them. Like foxes, you’ll need to sink your fencing about a foot deep and curled outwards so they can’t dig under.
You’ll also have to secure fencing over the tops so they can’t climb over them. Learn more about humane raccoon control in our guide.
12. Bears
If you live in bear country, then you’ve likely been warned about wandering around and foraging berries from places where they congregate. Now, if you’re growing your own berries and bears mosey on through your property to get to them, that’s a different story.
Some can be frightened off by bright motion-sensor lights or strong scents.
For example, some people soak cloths in ammonia or pine oil and spread those around the area, both to mask the berries’ scent and to dissuade the bears, as they have sensitive olfactory systems.
That said, if bears are intent on harvesting your berries, there’s little you can do to stop them. They’re generally strong enough to break through fencing and not fun to face off against. Better to let them eat some fruit than risk injury by confronting them.
In addition to the predatory raspberry pests mentioned above, these plants are vulnerable to a number of different diseases.
13. Powdery Mildew
If your region is prone to humid summers, then you’ll likely have to deal with powdery mildew at some point. Caused by the fungus Sphaerotheca macularis, it appears as soft, white, powdery-looking areas on your plants’ leaves—rather like they’ve been dusted with corn starch or talcum powder.
Although it’s not one of the more common raspberry problems, it can appear if the pathogen has been present in the area before or if there’s a bloom due to a sudden hot and damp spell.
Should you catch it early, you can snip off the affected areas and treat the rest of your plants with fungicide spray in an attempt to fend it off. If that doesn’t work, however, the only option is to cut the canes down and burn them.
To avoid this issue, try to plant your raspberry bushes in an area where they get full sun. Space them out well, and prune excess foliage so there’s plenty of airflow and light access.
14. Septoria Leaf Spot
This fungal pathogen (Septoria rubi) primarily affects blackberry and black raspberry bushes, but can occasionally spread to other Rubus species as well. It manifests as brownish spots with lighter centers on your plants’ leaves, followed by leaf yellowing and drip.
As it progresses, your bushes’ growth may be stunted, and several canes may die.
Although copper-based fungicides may be effective, the best option is to aggressively cut down or pull up affected plants and dispose of them. With fire.
15. Anthracnose
Anthracnose is a fungal disease from the Colletotrichum family, and like so many other raspberry pests, it thrives in cool, wet weather. The spores overwinter under leaf detritus and emerge in the springtime to attack your plants before dry heat kicks in.
As such, you’re unlikely to see this issue in high summer, but it’ll probably make an appearance once autumn rolls around again.
This pathogen causes dark, somewhat sunken discolorations and lesions on your raspberry bushes’ leaves, stems, and fruits. On the leaves, these discolorations will expand and spread so the leaves turn dark brown before falling off.
Very few fungicides have any effect on anthracnose, so prevention is your best option. Keep the area clear of detritus, ensure plenty of airflow and light access, and destroy any plants that seem affected.
Learn more about anthracnose and how to treat it in our article.
16. Cane Blight
If there are dark brown lesions on your raspberry canes, then you’re likely dealing with the insidious cane blight. It’s caused by the Leptosphaeria coniothyrium pathogen, which thrives in warm, damp conditions.
Once the lesions have formed, they enlarge until the canes are no longer able to support themselves and wilt over.
Copper- and sulfur-based fungicides are effective when this pathogen is in its early stages, but once established, the best option is to destroy any affected plants. Then remove all plant detritus, apply fungicide to the area, and prune back foliage for better airflow.
Additionally, laying down mulch around your canes may prevent splash-back when watering. Since the pathogen lives in soil, this can prevent it from leaping onto your canes.
17. Fire Blight
Do you have shriveled plants with dried-out-looking leaves, cankers on the stems, blackened cane tips, and brown, rotting flowers? Then you’re likely dealing with “fire blight.” This is a bacterial infection caused by Erwinia amylovora bacteria, resulting in plants that look as though they’ve been scorched in a fire.
Copper-based sprays can help to keep this issue in check, but if it doesn’t help much then your best bet is to pull out and burn all of your canes. Don’t plant any Rubus species there for at least five years, and change out the soil if possible before planting anything else.
When it comes time to prune your plants, ensure that you sterilize them with alcohol swabs between cuts so you don’t risk cross-contaminating any of your canes.
18. Botrytis Fruit Rot (Gray Rot)
If your raspberry fruits look gray and fuzzy, then you’re likely dealing with the Botrytis cinerea pathogen. It’s a fungus that thrives in cool, damp conditions, and renders your plants’ fruits inedible.
You can try to avoid this fungal issue by planting resistant varieties, spacing your plants well, pruning excess foliage, and watering at root level rather than from above. Additionally, ensure that you eliminate as much detritus from the soil around your plants as possible.
Spores can live in the earth for long periods of time, and they thrive under damp, rotting leaves that have fallen. Rake these away and trim off low branches so sunlight and airflow can get in there.
The fungus B. cinerea has become immune to most chemicals. Learn more about control in our guide.
19. Phytophthora Root Rot
Phytophthora fungi species, including Phytophthora infestans, P. cinnamomi, and P. ramorum, are some of the most notorious raspberry pests you’ll come across. They thrive in moist soils and will stunt and/or wilt your plants faster than you can blink.
Raspberry canes do best in very well-draining soil: if they have “wet feet”, they’re incredibly vulnerable to this fungal disease. Be very selective about where you plant your canes, and you should be able to avoid it.
There’s no treatment for this pathogen, so if it shows up, all you can do is uproot your plants and burn them in the hope of preventing its spread.
20. Mineral Deficiencies
Like all other life forms, raspberry bushes can suffer from mineral deficiencies. One of the most common issues is low iron, which can result in drooping, yellow leaves.
Calcium deficiency can manifest in blossom end rot in the fruits, while low nitrogen can result in stunted plants that have pale leaves instead of rich green ones. Test your soil to see what minerals may be lacking, and amend accordingly.
21. Sun Scalding
Again, this isn’t a “pest” per se so much as a situation or maintenance issue. If you find that your raspberry plants’ leaves and berries are getting light spots, and you’ve ruled out any kind of fungal pathogens, then they’re likely being sun scalded.
This often occurs in very hot climates, but can also happen if there’s too much moisture on the leaves at the hottest point of the day.
Never water your raspberry plants from above, as the water droplets act as miniature magnifying glasses when the sun’s rays hit them. These will burn (scald!) and bleach out the leaves, damaging them badly.