16 Sunflower Pests and Diseases and How To Handle Them

Who doesn’t love sunflowers? These beautiful flowers are symbols of hope all over the world, as they turn their bright, happy faces forever as the sun sets. The bad news is that there are a host of sunflower pests and diseases that can bite before these beauties have a chance to thrive.

Let’s take a look at some of the most common issues you’re likely to encounter when growing sunflowers. Some are easier to deal with than others, but everyone has their own improvements.

Common Animals and Pests Sunflower Pests

I don’t usually like to use the word “insect” when it comes to animals, but it is an accurate term. After all, dealing with these critters is a pain in the back, especially when you find yourself screaming and chasing them down with a broom in the middle of the night.

1. Raccoon

In my experience, raccoons are the worst interlopers when it comes to eating sunflowers. They will eat sprouts, young plants, buds… everything. Keep your flowers well away from walls or fences that these people can easily climb. Then, mix the olive oil with the garlic and cayenne pepper, and use a paintbrush to spread it over the stalks.

Raccoons have sensitive noses and will be put off by these strong, biting odors. I’ve found that they hate the smell of lavender, too, so a little bit of Dr. Bronner’s Lavender Castile soap (diluted in spray) is a good deterrent when sprinkled around their stems.

2. Squirrel

Unlike raccoons, squirrels will only pull out your sunflower plants when they are under a foot. That is until they mature and develop seed heads. Then, they will scrape off the stalks, gnaw off the ends, and do unspeakable things for the seeds.

Protect your sunflowers by planting really prickly thistles around them so they can’t get close. Also make baffle cones under the flower heads out of plastic. You know those ridiculous cones you put on dogs’ necks after surgery so they don’t pull their stitches? Like those, with the opening facing down. Squirrels won’t get past them, thus saving your seeds for future snacking.

3. Birds

Did you know that other animals like to eat sunflowers? Bird. They won’t go away after planting, but they will destroy the seed heads when they begin to mature. You can cover them with really fine bird netting to keep them away. The same kind of mesh you use for floating row covers works best to keep butterflies away from your brassicas.

Once the tops of the seeds begin to mature, you can also cover them with a large paper bag.

Believe it or not, a scarecrow will do the trick too. Sometimes, they’ll also keep raccoons away, especially if you hang aluminum cans or plates such as noisemakers. If you don’t want to make a scarecrow, hang some Christmas tinsel from the plants. Movement and brightness should drive away almost all species except magpies and crows. Because shiny.

4. Ants

You might think I’m kidding here, but I’m not. Most people don’t think of ants as common pests of sunflowers, but they certainly can be! Whenever I used to plant sunflowers I kept losing them and thought I was dealing with some sort of rotting disease. The stalks seemed to dissolve just above ground level, which is usually a sign of a soil-borne pathogen.

Wrong-o. It turns out that I was planting them in an area claimed by local ants. How did I find out? I went out early one morning and saw them munching on the stalks until the shoots were uprooted. Instead of destroying these insects on their home ground, we planted a new batch of seedlings elsewhere, and they have been thriving ever since.

5. Locusts

Like the locusts of biblical plague proportions, a horde of locusts can wipe out an entire sunflower field in a matter of days. We had a huge wave of them last summer, and they ate everything that grew on the property. Fortunately, toads and snakes absolutely love to chew on young grasshoppers.

Plant your sunflowers near a pond, if you have one, or provide a good water source for toads and frogs. They will help keep the hopper population down around your crop.

6. Sunflower Beetle

If sunflower beetles eat the leaves of larger plants, they won’t be able to do much damage. Where there are problems is if they get their mandibles on smaller plants. They won’t just eat the true leaves: they’ll also eat their way through the stems and buds. However, you know what is a great deterrent to beetles? double sided tape.

Wrap the base of your sunflower stalk with medical gauze for protection, and then wrap it in double-sided sticky tape. This will catch all kinds of predatory insects that are just itching to attack your flowers.

7. Sunflower borer

Sunflower borers and stem maggots burrow into the stems of sunflower plants to feed. It can kill especially large numbers of vegetation and other parts of sunflower plants quickly. Sadly, once these appear there’s really not much you can do to treat them. They live in the soil, and you won’t know they’ve wreaked havoc until it’s too late.

Destroy affected plants, and avoid repotting sunflowers there for at least two years. Practice crop rotation regularly to bring the larvae to the surface for the birds to eat, and until well done.

8. Cutworm

True to their name, these insects “bite” through whatever leaves they are crawling on. They prefer to nest in mud hollows during the day and emerge at night. Besides pesticides, there are some good ways to fight these bastards.

One is the sticky tape above on your sunflower stalk. Another is to let your chickens roam through the sunflower stalks. They are often quite fond of cutworms and will take them out of their day’s clogged pores for breakfast. If you don’t have chickens, borrow a couple for a few days.

9. Aphids

Are there any plants that these creatures won’t attack? I hate these idiots. Okay, so they don’t like strong scents, so be sure to plant plenty of garlic cloves, sage, and nasturtiums around their flowers. Spray the plants with neem oil, and scatter some diatomaceous earth around for good measure. Oh, and be sure to offer plenty of ladybugs if you don’t already have them.

There are more tips in our guide.

10. Sunflower Pests

Did you know that there is such a thing as a sunflower moth? I did not either. Well, not until I found their tiny little larvae roaming around inside my sunflower flowers. I’ve never been to the UK, but they are fairly common throughout the United States and Canada. species is homoeosoma electalum, and they hunt other asteresia family members, especially echinacea spp and Jerusalem artichoke (Helianthus tuberosus)

Plow the soil deeply before sowing to kill any eggs or larvae. Oh, and choose insect-resistant sunflower strains whenever possible.

sunflower diseases

In addition to the sunflower pests mentioned above, these flowers are susceptible to many different fungal diseases and scorch.

11. Sunflower Rust

This Fungus Loves Sunflowers and Others helianthus Species (like those succulents we mentioned earlier). It is challenging to eradicate, as it can survive winters down to -40°F. It prefers a cool, moist environment, and clings to leaf and stem detritus. This is one of the most common as far as sunflower pests and scorch diseases are concerned.

You can try to avoid this by removing any leaves or other residue left behind by your sunflower plants. To treat it, dissolve 10 plain aspirin tablets in a gallon of water, and spray it on the plants every few days.

12. Stem Cancer

It usually appears in hot, humid environments after a lot of rainfall. Brownish-black lesions appear on the stems and rot, killing their way to the plants. Most people use heavy-duty fungicides to treat it, but sometimes a stronger garlic spray can work.

If your plants get stem canker, destroy them by burning them, remove any weeds or dirt, and treat the soil below. Then do not plant again for at least five or six years.

13. Leaf Spot

You will recognize this fungus problem when it shows up. Black spots appear on the leaves, which wither and then fall off the plants. Choose disease-resistant varieties, and make sure you don’t grow sunflowers in the same location for five years. (Seriously, this is the healthiest way to cultivate them: The crop circle is your friend.)

If it turns up, you can treat it with garlic spray or diluted cider vinegar and hope for the best.

14. Gray Mold

Are your sunflower plants covered in fuzzy gray mold? Yes, it will happen… especially in hot, humid summer weather. If this is a problem in your area, be sure to choose disease-resistant varieties. Treat the seeds with a fungicide (such as soaking them in garlic water) before planting and make sure you fertilize the soil well.

To treat gray mold, use diluted apple cider vinegar or an aspirin spray.

15. Powdery Mildew

Who doesn’t love this stuff when it shows up? Yes, that was sarcasm. Powdery mildew can attack any plant and it looks like your plants have been dusted with talc or icing sugar. As with other fungal sunflower pests, be sure to choose disease-resistant varieties whenever possible. Remove any dirt from around plants, and treat mildew with apple cider vinegar or aspirin spray.

16. Black Stem

I’ll be honest with you here: I’ve only encountered black stems once and wasn’t able to successfully treat it. My approach was to treat it with organic, homemade fungicides that normally work well on my other plants. It didn’t work on black stems, and nursery staff recommended a fancier chemical fungicide instead.

I decided not to go that route and instead destroyed (burned) the plants. You choose the method that works best for you, but I would rather destroy some plants than add potentially dangerous chemicals to my soil.

Best practices to avoid problems

These are the main sunflower pests and diseases you will likely encounter when planting. Remember that there are many disease resistant varieties out there that repel pathogens and pests well. Keep your soil healthy and well fed with a balanced fertilizer, and practice crop rotation regularly.

Always rotate your sunflower beds, so you don’t grow in the same spot until five or more years have passed. Select healthy cover crops to replenish the soil in between, turning the soil deeply enough to kill the fungicide by the hot summer sun.

When you grow a successful sunflower crop, you’ll have an amazing sense of accomplishment that these techniques have worked so well. And as a bonus, you’ll have tons of delicious seeds for breakfast.

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