How to Identify and Control Sunflower Pests In Your Garden

How to Identify and Control Sunflower Pests In Your Garden

Bold, cheerful, summery, and even delicious, sunflowers are a plant that just about everyone knows and seems to love. Unfortunately, they love pests too! Don’t worry, we’ve got you covered with everything you need to know about who might have access to your nibble sunglasses, what they look like and what to do with them. Let’s learn how to Control Sunflower Pests right here.

How to Identify and Control Sunflower Pests

The list of pests that love to nibble on sunflowers can be a little daunting, but it’s easier to understand and plan for if we break it down into groups of insects that require attention at different stages of plant development.

Seedlings attract cutworms, nematodes and sunflower beetles.

Watch out for sunflower beetles, thistle bugs, and stem weevil during plant growth, when plants develop tall stems and large leaves

What to look for when

The list of pests that love to nibble on sunflowers can be a little daunting, but it’s easier to understand and plan for if we break it down into groups of insects that require attention at different stages of plant development.

Seedlings attract cutworms, nematodes and sunflower beetles.

Watch out for sunflower beetles, thistle bugs, and stem weevil during plant growth, when plants develop tall stems and large leaves


Regardless of the species, aphids are tiny insects that suck on leaves, tender stems, and petals. They also secrete honeydew, which ants and painted butterflies like to feed on, and which breed black mold.

Insecticidal soaps, like this one from Bonide from Arbico Organics, are effective against aphids and are safe for pollinators when used correctly.


Several species of caterpillars find new sunflower seedlings delicious. In fact, farmers are advised to plant borders of sunflowers around gardens or fields to lure cutworms away from other crops.

Leaf lesions look like small transparent parts chewed on by larvae, nicks, and blights. But cutworms get their name from their habit of cutting plants at the soil line, a very distressing symptom.
Most caterpillars feed at night, hiding a few inches below the ground from plants. To find them, dig carefully into the soil around the plant, looking for fat, soft, wrinkled brown or gray larvae.

Preventative measures include weed control, as weeds will find shelter and feed on cutworms before the plants grow. Till the soil in the fall to expose larvae and pupae to hungry birds. Hand pick the larvae after watering or raining at night, or let your chickens do the work for you.

Cutworms like to live in the grass, so leave a three-foot strip of bare soil between the lawn and the yard. This makes it difficult for the larvae to reach your plants.

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When planting, build a homemade barrier around each seedling. Cut the bottom of the milk carton and insert it two inches into the soil to surround the seedling.

You can also spread a layer of diatomaceous earth around the base of each seedling as a lethal barrier.

Try Perm-Guard Crawling Insect Control from Arbico Organics.

Beneficial nematodes from Arbico Organics, specifically Steinernema carpocapsae, attack larvae in the soil and are safe for everyone including bees!

Alternatively, you can use a Bacillus thuringiensis product from Arbico Organics, such as Monterey Bt Liquid. This is another safe and effective option for pollinators.

Read our full guide to controlling cutworms here.

Blind Bugs

Lygus beetles (Lygus spp.) range from green to reddish-brown with a prominent bright triangle at the base of their wings.
The nymphs are green, look like aphids, but move faster and don’t have the “tail tube” (cartilage) characteristic of aphids.

Lupus beetles feed by injecting enzymes that digest plant tissue into plants and sucking out nutrients. Feeding the seeds causes brown spots, also known as core brown spots, and has a bitter taste. This can be a serious problem for farmers and home gardeners when planning to harvest snack seeds.

Lycium bugs are difficult to control because they move so fast that it is difficult to catch them with a spray. If you decide to use insecticide for a severe infestation, use it early in the morning when the beetles are less active. Use insecticidal soap as you would aphids.

Sunflower Beetles

Zygogramma exclamationis are easy to identify. They are round beetles with a reddish-brown head and beige wings covered with reddish-brown vertical stripes.

The larvae are almost cute, with thick bodies, pale green to yellow, and cone-shaped. Adult feeding will create bullet holes in leaves, and larvae will eat transparent windows in leaves.

Unlike the pests discussed above, sunflower beetles are specific to sunflowers. They are the most destructive defoliants of North American sunflowers.

Often, beetle populations are controlled by nature’s beneficial insects. Various ladybugs, such as the thirteen and astringent varieties, eat eggs.

Lacewings eat eggs and larvae, and scarabs, two-spotted bed bugs, and ground beetles also target larvae.
Planting later in the season can help reduce leaf fall. Neem products like AzaSol from Arbico Organics are also effective.

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Sunflower Moths

Homoeosoma electellum can be a serious pest of cultivated sunflowers. The adults look like tan cigarillos, and the larvae are brown with white vertical stripes.

These imaginings are mostly nocturnal, resting under leaves during the day and laying eggs on flower heads. Look for dark detritus (aka worm droppings) and nets on flower heads, indicating that larvae are feeding inside.

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Larvae feed on pollen, while older larvae feed on seeds and flower head tissue. Feeding damage caused by the larvae increases the risk of infection by the fungus Rhizopus, which can rot flower heads.

In the wild, more than half of the larvae are parasitized by wasps. Large areas of large-headed cultivated sunflowers provide larvae with a large number of available safe havens, thereby reducing the efficiency of parasitic wasps. But even small plants like your garden deserve protection from these beneficial insects!

Some sunflower varieties do not produce pollen. This deters pests that feed on pollen at one or more life stages. Read about some of the best pollen-free strains in this guide.

Try a Bacillus thuringiensis product like Monterey Bt Liquid to treat plants affected by these larvae. Insecticidal soap or neem-based products like AzaSol are also optional.

Sunflower Midges

Contarinia schulzi is a small midges that lay eggs on sunflower heads, and the larvae feed on the tissue of the developing seeds and bracts. This results in low seed yields and twisted, knobby flower heads.

Damage usually does not spread widely. Delaying planting for a few weeks can help reduce the risk and severity of potential infestations.

Try to rotate where you plant your sunflowers each year so you don’t plant directly into an infected area. Some hybrids are resistant to mosquitoes, so keep an eye out for these if these insects have been a problem in the past.

Insecticides are ineffective because the tiny mosquito larvae are well protected in the sunflower head.

Thistle caterpillars

The beautiful nectar-loving larvae of the Painted Lady (Vanessa cardui), thistle caterpillars love a good sunflower snack.

They come in a variety of colors, from light green to black, with light stripes on the sides and bifurcated spines all over their bodies.
The larvae feed on leaves, forming irregularly shaped holes and covering themselves with nets.

The damage is usually minor and doesn’t require treatment, but it’s good to know who’s chewing on your precious plant. If these pests are a problem, fight them like sunflower moths.

Identify and Control Sunflower Pests
Identify and Control Sunflower Pests


There are several different weevil species that feed on sunflowers, including the head beetle (Haplorynchites aeneus) and the grey (Smicronyx sordidus) and red corn weevil (S. fulvus).

You know it when you see a weevil. They have long trunks like elephants!
Weevils are good at playing dead, so finding adults is difficult. The shadows of flying birds or your rustling in flower beds can cause them to harden and fall off the plants as if they were dead.
Head-cutting weevil can cause damage you can’t ignore. They bundle the flower stalks or leaf stalks, leaving the partially severed heads and leaves hanging sadly from the plants.

Gray and red weevil, each of the colors that have their names, are the most common harmful pests of sunflowers, with red weevil being the most common of the two. The adults feed on pollen and lay eggs in the developing seeds, and the larvae hatch and eat.

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The same product that works on sunflower moths also works on rhinoceros. Concentrate on the back of the flower head and apply a neem product or insecticidal soap. The best times to control sunflower moths and weevil often overlap, and when both pests are present, you can kill both bugs with one application!

Because the weevil larvae drop into the soil to pupate, the beneficial nematodes can be very effective at preventing future infestations.

Make sure the product you choose contains the nematode species Heterorhabditis bacteriophora.
NemaSeek Hb Beneficial Nematodes is a good option, available from Arbico Organics.

Wireworms and Darkling Beetles

Species from the nematode family Elateridae, as well as pseudonematodes from the family Tenebrionidae, love sunflower snacks.
The adult nematodes are called click beetles and come in a variety of colors. Nematode larvae have a keen sense of smell and move towards the smell of carbon dioxide emitted by the seeds as they germinate. They are white to brown, very slender, and have a hard, articulated body.
The larvae feed on the underground parts of plants, including seeds and roots. As a result, the plants turn yellow and wither.

Different colored pseudonematodes or dark beetles can also be seen. Their stubborn larvae look a lot like nematodes and are creamy, yellow or brown in sheen. They also feed on sprouted seeds, so it can be difficult to tell the difference between the two.

Prevent infestation of these two pests by removing all plant debris from the garden and cultivating the soil to expose the worms to predators. After plowing, let your chickens run free or pick them yourself and drop them into a bucket of soapy water.

If you see signs of yellowing, it may be difficult to tell if it’s a nematode problem. Try this trick to catch worms:

Cut potatoes in half and skewer them on skewers. Bury the potato, leaving part of the stem so you can find it again. Pull it out after a week to see if the nematodes feed on it.
Try using beneficial nematodes such as Steinernema carpocapsae from Arbico Organics for nematode control.

Generally, a small patch or row of sunflowers you grow in your garden won’t see half of these pests, but when they do, you now have a knack for controlling them! Have you ever had an insect problem with your sunflowers? Tell about it and how you dealt with it in the comments below, or feel free to contact you if we haven’t answered any questions.