Beautiful flowers that bloom all summer, ample pollen to attract pollinators, and seeds that can be enjoyed by many backyard friends—it’s no wonder why gardeners love sunflowers. Unfortunately, sunflowers are loved by several pests too.
Luckily though, you can repel most sunflower pests by covering developing buds, using row covers to keep pests away from seedlings, and adding plants that pests dislike to your garden.
But, you really need to know what pests you’re dealing with in order to take the appropriate defense measure. That’s where we come in!
Join us as we take a closer look at some of the most common sunflower pests and ways to keep your sunflowers safe from each of them.
Grasshoppers Eat More than Just Grass
Grasshoppers can be found in almost every type of habitat in the world. In small numbers, they cause very little harm to a garden and can even be beneficial because they eat certain weeds. But will grasshoppers eat your sunflowers?
Grasshoppers can and do eat sunflowers. Smaller populations will usually focus primarily on the sunflower leaves. In contrast, larger populations might attack the entire plant, including the leaves, stalks, flowers, and seeds.
What a grasshopper looks like will depend on what species it is. They’re typically between one and seven centimeters long and are easily identified by their large back legs, which they use to jump several feet into the air. Some grasshoppers can fly, while others depend on their legs to get around.
Most grasshoppers are solitary and live by themselves. However, some species will collect to form swarms. A large swarm can wipe out an entire crop of plants or flowers in just a few days.
Although you probably won’t have to worry about a swarm, a healthy population can still do quite a lot of damage to a flower garden.
In case you’re interested in grasshoppers specifically, take a look at our guide on the reasons why grasshoppers are attracted to your yard!
How To Identify Grasshopper Damage
Grasshoppers can eat as much as half of their body weight in food each day. It’s important to keep populations low to minimize damage. But how can you tell if grasshoppers are responsible for the destruction in your garden?
Grasshopper damage will appear as small rounded holes between the veins of a leaf or as large sections of a leaf or flower chewed away from the outside-in. You might also notice small holes in vegetables or stalks.
Visually inspecting your plants during the day should help you estimate how many grasshoppers are currently living in your garden. Grasshoppers eat during the day and rest at night, making it easy to catch them red-handed (or green-mouthed).
If you don’t see any grasshoppers but still believe they’re around, look for eggs in the soil and the skin shells that nymphs shed in the spring. The appearance of eggs will depend on the grasshopper species, but they are almost always found in soil.
Tips For Repelling Grasshoppers From Sunflowers
Having a few grasshoppers in your garden is not the end of the world. Still, in higher numbers, they can significantly damage a sunflower plant. Luckily, there are ways to reduce the number of grasshoppers in your yard.
- Give them something better to eat. Grasshoppers typically live in areas where tall grass is present. Not only does it give them food, but it helps them hide from predators. If they have a more sheltered place to feast, they’ll likely choose to hang out there instead.
Devote a section of your lawn to tall grasses and plants. You might choose to create a flower bed specifically for this or allow an area of your property to grow naturally.
- Speaking of predators, drawing natural predators in can help you control grasshopper populations. It turns out that grasshoppers are a big part of the food chain and numerous animals and insects depend on the bugs for nourishment. Birds, lizards, frogs, shrews, wasps, ants, and many other predators can be lured to your yard to help eliminate grasshoppers.
- Make your garden less desirable by planting things that grasshoppers dislike. Like any living thing, grasshoppers are attracted to foods they like to eat and steer clear of what they dislike. Planting things like cilantro, garlic, lilacs, artemisia, horehound, and calendula around sunflowers can protect them from grasshoppers.
- Utilize scents that grasshoppers hate. Even though they don’t have noses, grasshoppers can smell due to olfactory receptors in their antennae. Use this to your advantage by learning more about the scents grasshoppers hate and how to use them.
If all else fails, you can try catching grasshoppers with sticky traps like these Extra Large Insect Traps from Maxguard. Keep in mind, however, that these traps don’t discriminate and might trap beneficial insects too.
Sunflower Moths Could Be Destroying Your Sunflowers
Although their name sounds enchanting, these tiny moths are feared by sunflower gardeners everywhere. But what are sunflower moths, and do they eat sunflowers?
Sunflower moths are tiny silver-gray moths. They’re attracted to the scent of newly blooming sunflowers and lay their eggs on the bracts of developing buds. The larvae cause significant damage to sunflowers, and infestations can lead to head rot.
Adult moths are silver-gray and grow between 9 and 11 mm in length. Some species, such as the banded sunflower moth, will appear tan and have a dark band on their wings.
When at rest, the moths pull their wings close to their body, giving them a unique tubular appearance.
Sunflower moth larvae feed on different parts of the flower during each stage of development.
First instars feed on the pollen of the host flower. Second instars feed on pollen too but will also eat the corollas (petals). Third, fourth, and fifth instars begin to attack the flower’s ovaries (seeds), which hinders the flower’s reproductive actions.
According to Texas A&M University, one sunflower larva can eat up to 12 seeds during its short 15-19 day development stage.
How Do I Know If I Have Sunflower Moths?
Since you might have to use different methods to repel certain sunflower pests, it’s always a good idea to know which ones you’re targeting. Fortunately, the signs below will help you determine if you have sunflower moths in your garden.
Signs to look for before your sunflowers bloom:
- The presence of adult moths
- Tiny white eggs on the bracts of developing flower buds
Signs to look for after your sunflowers bloom:
- Dark frass
- Holes in the top of sunflower seeds
- Larvae inside the seeds
- Silk webbing on flower heads
- Visible sunflower moth larvae
- Head rot
- Larvae descending from the flower to the soil on silk strands
Adult sunflower moths are nocturnal and will rest under leaves or vegetation at the edge of a sunflower field or garden during the day. They’ll often emerge around twilight to mate, eat, or lay their eggs.
Look for moths during the day and watch for activity during the evening hours. You can also use pheromone traps like these Pantry Moth Traps with Pheromones to determine if you have adult moths in the area.
The moths often lay their eggs on developing sunflower buds during the R2 or R3 stage. R2 and R3 refer to the stage when the bud will be nearly ready to open, and the top leaf will be about an inch from the bud.
Sunflower moth eggs are tiny, and you may find them alone or in small clusters. Because the eggs are so small, it’s recommended to use a magnifying glass to find them. Look on both the outside and inside bracts.
Newly hatched larvae will be a pale color and minuscule in size. As the larvae grow, they’ll become darker and have visible stripes along their body. These stripes may appear tan, brown, white, or purple.
It’s important to note that sunflower moths will attack other flowers as well, including:
- Black-eyed Susans
Tips For Repelling Sunflower Moths From Sunflowers
The most common prevention method calls for the use of insecticides. However, they could be dangerous to you and other garden visitors. For this reason, it’s highly recommended that you contact a professional in your area before using insecticides.
- Draw in natural predators. Sunflower moths have many natural predators, including birds, bats, parasitic wasps, and flies. Inviting these into your garden could reduce sunflower moth activity. Just make sure you’re not calling in anything that might also eat your sunflowers!
- Bring sunflowers in at night. Since sunflower moths usually lay their eggs in the evening, moving your potted flowers indoors overnight could prevent moths from laying eggs on them.
- Cover sunflower buds with mesh bags. Prevent moths from laying eggs on the developing buds by covering them with these Garden Netting Barrier Bags. The fine mesh netting and drawstring design will keep moths from growing buds.
- Use dish soap and water to eliminate eggs and larvae naturally. If you notice signs of sunflower moth larvae on your mature flowers, spray the heads with a mixture of dish soap and water. Add 1-2 teaspoons of dish soap to a quart of water and spray the flowers every few days.
- Remove infected flower heads from your garden. If your flowers are severely destroyed or starting to show signs of head rot, remove them from your garden to prevent the infestation from moving to other plants.
Cut the flower head off and place it into a sealed bag. Be sure to dispose of it far away from your garden to ensure the larvae do not pupate through the winter and target your flowers next year.
Sunflower Maggots May Be Causing some Damage
The last place you’d expect to find maggots is inside a flower, but apparently, that’s exactly where these little pests like to start their life. But what are sunflower maggots?
Sunflower maggots are the larval form of the sunflower maggot fly. The larvae will bore into and eat the seeds and stalks after hatching. Although damage is typically minimal, stalk breakage can occur.
There are three species of sunflower maggot flies. Each species has a distinct brownish-yellow pattern on its wings. This pattern has earned them the nickname “picture-wing flies.”
The Sunflower Receptacle Maggot is the largest of the three. Adult flies lay their eggs on the bracts of developing buds. Once they hatch, the larva burrows into the sunflower receptacle. They reside here for about a month before dropping out of the flower into the soil below.
Sunflower Maggot Flies are a bit smaller than their older relatives. Adult flies lay their eggs in the stem tissue of developing sunflowers. The larva feeds on the pith inside the stem and stalks before pupating.
Sunflower Seed Maggots are the smallest of the three and attack the head of the sunflower. The larvae can be found tunneling into the seeds, where they eat the kernels. You may also observe brown pupa in the flower head.
If you observe small, white maggots in or on your sunflowers, or brown pupa on the face of your sunflowers, it’s likely that a species of sunflower maggot fly is to blame.
Tips For Repelling Sunflower Maggots
Because sunflower maggots won’t usually cause significant damage, gardeners may not even realize they have them. Still, there are a few ways to protect your flowers from creepy crawlies.
- The best way to prevent maggots from hatching on your sunflowers is to prevent flies from laying eggs. Research picture-wing flies in your area to see what months they typically appear so you’ll know when to start watching for them.
- Cover buds with netting or mesh bags to keep flies from laying eggs on the developing flowers. To protect your sunflowers, you can also use row covers like Flarmor’s Floating Row Covers.
- Growing sunflowers in a greenhouse can also prevent egg-laying pests from targeting your flowers. Screen houses, like Gregin’s Screen House Mesh Net Canopy Tent, can work wonderfully for taller plants like sunflowers.
- Inspect your sunflowers and remove any larvae or pupa that you see. This will prevent the pupa from hatching a new generation of destructive pests.
Aphids Feed On Sunflowers
Aphids are one of the most common insects in a garden. They can be found feasting on various plants, but do aphids damage sunflowers?
Aphids are tiny insects that feast on a wide range of vegetation, including sunflowers. They feed by sucking nutrients from various parts of the host plant and can cause damage to the leaves and stalks of sunflowers.
Aphids may target certain plants, or they may feed on a variety of vegetation. If you find aphids on your sunflowers, there’s a good chance they’re either melon or sunflower aphids.
You can read about the reasons you have aphids in your garden here for a more in-depth look at what is attracting aphids to your garden, aside from your sunflowers.
Aphids are small, pear-bodied insects that range in color from yellow, green, brown, red, and black. Some species have wings, while others are flightless. All species have cornicles (two tubes that protrude from the back of their abdomen).
Identifying Aphid Damage On Sunflowers
Most plants can withstand a small amount of aphid activity. However, larger populations may cause significant damage.
Signs of aphid activity include:
- Large clusters of insects congregating on leaves or stalks
- Leaves that have become yellow or wilted
- Stunted growth in plants
- Deformed leaves or flowers
- Presence of honeydew
- Presence of shed skins
- An abnormally high number of ants on your sunflower plants
Because aphids feed by inserting their mouthparts into the plant and sucking out the nutrients, leaves may become yellowed or disfigured. Additionally, young plants may become deprived of the nutrients they need to grow and can become deformed.
You can also look for the presence of honeydew and ants. Aphids excrete honeydew while feeding, and ants will commonly harvest this excretion. If you see honeydew or an abnormal amount of ants on your sunflowers, you likely have aphids.
To add, if you’re dealing with aphids in your garden, here are some common vegetables that they love in order to identify the damage they cause on other plants!
Tips For Keeping Aphids Away From Sunflowers
Aphids reproduce very quickly. For this reason, it’s important to take measures to eliminate the pests as soon as you recognize the signs of an infestation.
Because aphids are so small, it’s hard to manually remove them. Still, it’s always a good idea to terminate any aphids you find on your plants.
- Plant things that aphids dislike around your sunflowers to repel them. Aphids dislike various plants, including garlic, mint, thyme, and lavender. Learn more about the scents that aphids hate and how to use them if you’d like to use natural repellents!
- Attract natural predators to keep aphid populations down. Ladybugs are aphid-eating machines. Just one ladybug can eat up to 50 aphids a day! If you want to attract ladybirds, check out these 4 ways to attract ladybugs to your garden.
Ladybugs aren’t the only ones who enjoy snacking on aphids. Lacewings, damsel bugs, earwigs, and several beetles can be lured into your garden to help eliminate aphids.
- Reduce ant populations in your garden. To protect their honeydew meal, ants purposely protect aphids from predators. Lowering the ant population in your garden will help keep aphids vulnerable to their natural predators.
Cinnamon and cayenne pepper can be sprinkled on the ground around sunflowers to keep ants away. Double-sided tape can also be applied to the bottom of sunflower stalks to keep ants from crawling up the plant.
- Spray plants with neem oil or soap and water. Make a mixture of water and 1-2 teaspoons of dish soap. Spray the mixture on the infested areas of the plant. Focus on the underside of leaves, stalks, and flowers. You may need to apply it every couple of days until the aphids are gone.
Cutworms Can Cut Down Your Sunflowers
Worms are beneficial to have in your garden for several reasons. So, why are cutworms feared by gardeners?
Cutworms are not worms at all. Instead, they’re the larval form of certain species of moth. They’re called cutworms because they often cut young plants off at the soil line.
Three species of cutworm cause damage to sunflowers—the Darksided cutworm, the Red-backed cutworm, and the Dingy cutworm.
The moths are harmless and won’t damage your flowers, but their offspring are a different story.
Cutworms may be brown, gray, tan, green, or black during the larval stage. They have a plump, grub-like appearance and curl into a “C” shape when disturbed.
The larva spends their days hiding in the soil and ground litter, emerging at night to feed on the stems and leaves of plants.
Identifying Cutworm Damage
Because cutworms feed at night, it might be hard to identify damage before it’s too late. Luckily, if you know what signs to look for, you can manage the pests before they kill your flowers.
Signs that your sunflowers are being attacked by cutworms include:
- Grub-like worms emerging to feed at night
- Damage to the leaves, stems, and stalks of your plants
- Plants that are wilting or dying for no apparent reason
- Seedlings that are cut off at the base
- Patches of damaged plants in a field or garden
- Black pellet-shaped droppings on the leaves or soil around the damaged plant
- Caterpillars that come out at night and curl into a “C.”
If you notice any of these signs, you’ll need to take action to save your plants.
Tips For Repelling Cutworms From Sunflowers
Cutworms can do a lot of damage in a short time, so prevention and quick action are essential when repelling these sunflower pests.
- Manually check your plants in the evening and at night. This can minimize the damage to your plants and reduce the number of cutworms in your garden. You can also check during cloudy days.
- Pluck cutworms off your plants and place them in a can of motor oil, dish soap, or water. The larva won’t travel long distances, so if you feel uncomfortable eliminating them, you can relocate them away from your home.
- Uncover pupa and cutworms by tilling your garden at the beginning and end of each season. This can stop the pupa from hatching and allows you to remove any that you uncover. Additionally, this will make your garden less desirable to adults looking for a place to lay their eggs.
- Place crushed eggshells around newly planted sunflowers. The sharp edges make it hard for the cutworms to crawl over the eggshells. And the shells will decompose, adding calcium and nutrients to your soil.
- Use toilet paper rolls to form barriers around the base of plants. Be sure to push the cardboard at least four inches into the soil to keep cutworms from simply crawling underneath the barricade.
- Sprinkle Epsom salt around sunflowers. Most soft-bodied pests avoid Epsom salt because it can scratch their bodies. Additionally, it can have a dehydrating effect on many garden pests.
- Place wooden skewers around the sunflower stalks. This is time-consuming, but it does work. Because the cutworms cannot chew through the wood, they won’t be able to cut the seedling down.
That’s A Wrap!
Although the pests listed above are some of the most common, they’re not the only ones who enjoy snacking on sunflowers. Luckily, there are a few universal ways to keep sunflowers safe from all backyard pests.
Use row covers to protect young seedlings. Plant mint, thyme, and lavender around sunflowers to deter various insects. Spray leaves, stalks, and flowers with neem oil or soap and water. Finally, cover developing buds and mature flower heads with mesh bags to protect them from egg-laying insects.
If you follow the tips above and keep a vigilant eye on your plants, you’ll be able to enjoy your sunflowers all summer long.
Charlet, L. D., Brewer, G. J., & Lincoln, N. B. (2009). Sunflower insect pest management in North America. Radcliffs IPM World Textbook. Regents of the University of Minnesota,[Internet].
Knodel, J. J., Charlet, L. D., & Gavloski, J. (2010). Integrated pest management of sunflower insect pests in the Northern Great Plains.
Royer, T. A., & Knodel, J. J. (2019). Sunflower Moth (Lepidoptera: Pyralidae) Biology, Ecology, and Management. Journal of Integrated Pest Management, 10(1), 25.
Sorensen, J. T. (2009). Aphids. In Encyclopedia of insects (pp. 27-31). Academic Press.
Zack is a Nature & Wildlife specialist based in Upstate, NY, and is the founder of his Tree Journey and Pest Pointers brands. He has a vast experience with nature while living and growing up on 50+ acres of fields, woodlands, and a freshwater bass pond. Zack has encountered many pest situations over the years and has spent his time maintaining and planting over 35 species of trees since his youth with his family on their property.
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