What’s not to like about petunias? They’re easy to grow, versatile, and bursting with every color you can think of. If you take good care of your petunias but they appear haggard or wilting, bugs and insects could be to blame.
Bugs and insects that eat petunias include thrips, whiteflies, cyclamen mites, spider mites, variegated cutworms, leafminers, and aphids. Since petunias bloom from spring to frost, the timing of the damage will depend on each pest but could happen through the entire growing season.
We’ll go over all the bugs and insects that are attracted to petunias and what the damage looks like. We’ll also cover some tips on how to repel these buggy pests from your petunias!
Thrips Love Eating Petunia Leaves
Thrips are very tiny, slender, winged insects that love chowing down on petunia leaves. If you look very close, you can spot them on petunia leaves, though they only measure around 1/20th of an inch.
Be on the lookout for thrip damage in spring through summer. Depending on the specific thrip species, they could be active at night or during the day.
Western flower thrips are a common species that prey on petunia leaves. According to the University of Massachusetts Amherst, thrips use sucking mouthparts to suck out the contents of leaves.
Check your petunias for these signs of thrip damage:
- Leaf scarring: While feeding, thrips will not create holes like other larger pests. They will only damage the top layer of the leaf, which causes the appearance of silvery scars.
- Dark flower petals: Thrips that feed on the buds of petunias can create dark spots on the flowers when they eventually bloom.
- Stunted growth: If thrips feed on the buds and terminals of the petunia before it properly grows, it will cause stunted growth.
The problem with thrip damage is that a lot of it happens before the petunias even bloom. This can make it difficult to control thrip pests since they may move onto a different host by the time damage is noticed.
For this reason, repelling thrips before you notice damage is super important.
How To Repel Thrips From Petunia Buds And Leaves
When it comes to repelling thrips, the best way to go about it is to repel them before you notice any damage. This way, your petunias can bloom happy and healthy.
There are a few ways you can monitor and repel thrips from your petunias, even if it’s before they bloom.
- Sticky traps: Use sticky traps early in the season to identify when thrips become active. They are attracted to yellow and blue traps. Seekbit’s Blue Sticky Traps work great to monitor for thrips and reduce their numbers.
- Minimize dust: Predatory insects that feed on thrips will benefit from the reduction of dust. If the weather is hot and dry, consider lightly rinsing off petunias and the surrounding area to minimize the amount of dust and encourage natural predators.
- Avoid pesticides: pesticides will reduce the number of natural predators that feed on thrips. Try to avoid using pesticides and insecticides as much as possible.
Whiteflies Chow Down On Petunia Leaves
Even though they are called ‘whiteflies,’ these tiny pests are more closely related to aphids than they are to flies.
Whiteflies feed on the sap of petunia plant leaves, leaving the flowers and stems intact. The most severe whitefly damage will happen during the hottest months of summer.
To identify whiteflies, check the underside of leaves. Whiteflies will settle here instead of on top of the leaf to avoid the eyes of hungry predators.
If whiteflies are to blame for damage to your petunia, you’ll see some of these signs:
- Yellow leaves: If there is a large population of whiteflies, feeding on the leaves can cause them to turn yellow.
- Black sooty mold: While feeding, whiteflies excrete a sticky substance called honeydew. When this substance coats the leaves, it often attracts sooty mold fungus, which will appear as black spots on the leaves.
- Leaf drop: When feeding is severe, leaves can become so damaged that they fall off the petunia plant.
How To Keep Whiteflies Off Your Petunias
Whiteflies hide out on the underside of leaves, making them difficult to repel and manage. However, there are a few things that will help keep whiteflies off your petunias.
- Manage ants: Ants are attracted to the honeydew from whiteflies. They will often protect whiteflies from natural predators to protect their source of honeydew. Consider using ant traps like Terro’s Liquid Ant Killer to remove ants and open up whiteflies to natural predators.
- Avoid insecticides: Insecticides will eliminate friendly predator insects that would have otherwise taken care of whiteflies naturally.
- Avoid pruning: Pruning promotes new growth on petunias, which will attract whiteflies.
- Encourage predators: Spiders, ladybugs, and small birds all prey on whiteflies. Try to plant a variety of plants to attract these beneficial bugs and spiders near your petunias. You can read more about how to attract ladybugs here.
When looking for whiteflies, check the underside of leaves. If you find whiteflies, you can use a garden hose to wash them off.
For a more in-depth look at what attracts whiteflies and how to get rid of them, check out our article on natural whitefly repellents!
Cyclamen Mites Love Eating Leaves And Buds Of Petunias
Cyclamen mites are tiny pests that can be white, green, or orange. They are so tiny that they measure just 1/100th of an inch and cannot be seen without aid.
Unlike whiteflies, cyclamen mites prefer cooler temperatures. You can expect the worst damage to occur when temperatures are steady at around 60℉, usually in the spring.
These minuscule pests can cause damage to petunias in several ways. Often, signs of damage are the only sign cyclamen mites are a problem since they are so hard to see.
- Curled leaves: Cyclamen mites feed by sucking out the sap of leaves, similar to aphids. As they feed, they will inject toxic saliva that causes the leaves to curl. This aids the mites in protecting themselves against predators.
- Discolored flowers: Cyclamen mites not only feed on leaves but also on buds. Once the flowers bloom, the damage to the buds can cause the flowers to become discolored and dark.
- Stunted growth: As cyclamen mites feed on buds and new growth, it can cause the overall petunia flower to become stunted or distorted in shape.
How To Stop Cyclamen mites From Damaging Petunias
It may seem impossible to control such tiny pests, but there are plenty of things you can do to keep them away from your petunias.
According to the University of Kentucky, petunias are highly susceptible to cyclamen mite damage, so it’s important to be on the lookout for the signs of damage listed above.
Once you have confirmed you have cyclamen mites infesting your petunias, take steps to minimize the damage and avoid its spread:
- Inspect petunias before purchase: When purchasing petunias at a garden center, examine them to make sure the flowers appear healthy. If you bring cyclamen mites home with you, they may infest other plants in the yard.
- Avoid dust: Consider gently hosing off petunias a few times a week and the area around petunias. This will encourage predatory insects to control mites naturally.
- Soak infested plants in hot water: If you have potted petunias that are infested with cyclamen mites, heat some water to 110℉ and immerse the entire plant, pot and all, for 15 minutes.
- Prune infested plant parts: Petunias that are planted in the ground cannot be uprooted to give them a hot water bath. Instead, prune off the infected areas of the plant or discard the entire plant.
Spider Mites Will Make A Home Of Your Petunias
Any gardener who has had experience with spider mites knows they are one of the worst pests to have. These small arachnids spin unsightly webs and infest petunia plants.
The twospotted spider mite is one of the most well-known pest mites, but Pacific and strawberry spider mites are also common problems.
Unlike cyclamen mites, spider mites can be seen with the naked eye, though the mites will appear as little more than moving dots on petunia plants.
Expect spider mite damage to ramp up during the hot months of June, July, and August. Check petunias for these signs of spider mites:
- Dots on leaves: spider mites feed by sucking out the contents inside of leaves. This leaves many small dots on the leaves, known as stippling.
- Webs: If spider mite populations are high, you will notice webbing that can cover any part of the petunia plant, including the flower, leaves, and stem.
- Leaf drop: When feeding is severe, damage to the leaves can be enough to cause them to wither and drop from the petunia plant.
Even if spider mite damage is high enough that you see visible webs on petunias, there is still time to save your plants!
How To Stop Spider Mites From Webbing Up Petunia Plants
Occasionally, spider mites will have already moved on once the damage becomes severe enough to notice. It’s important to identify whether mites are still present before treating.
Inspect the underside of leaves to identify mites. If none appear present, you can place a white cloth under the plant and gently shake the leaves. If any mites are present, they will fall off the leaves and move around on the white sheet where they will be easily visible.
If mites are no longer present on the petunia, the plant will recover nicely from any damage. However, if mites are still present, there are a few things you can do to get them off and keep them off.
- Predatory mites: It can be difficult to wait for natural predators to take care of spider mites. You can make this process faster by purchasing and releasing predatory mites yourself.
Predatory mites like Nature’s Good Guys 5,000 Live Adult Predatory Mites will not harm petunias but will target spider mites and help control the population naturally.
- Give petunias enough water: Spider mites will seize the opportunity to prey on water-stressed plants. They love hot, dry environments. Make sure you give your petunias adequate water.
- Avoid insecticides: Insecticides and pesticides are likely to cause more harm than good when dealing with spider mites. It will eliminate natural enemies that keep spider mites in check.
Variegated Cutworms Can Eat Your Whole Petunia Plant
Variegated cutworms are caterpillars that target petunias and hostas among other low-growing ornamental plants.
Typically, cutworms get their name from the clipping damage they do around the base of the stem. However, variegated cutworms do not do this. Instead, they climb up the plant and target the leaves, flowers, buds, and anything else they can devour.
Damage from variegated cutworms happens at night when temperatures are cool, and humidity is high. During the day, these wriggly pests hide out at the base of plants or in the soil.
Be on the lookout for signs of cutworm damage in early spring. Cutworm damage may appear on the leaves or the flowers of petunia plants:
- Holes in leaves: When cutworms feed, they leave behind large irregularly shaped holes in petunia leaves.
- Missing buds: Variegated cutworms can feed so heavily on emerging buds they destroy them. This can cause not only missing buds but missing flowers as well.
- Holes in flowers: Leaves and buds aren’t the only things that variegated cutworms will feast on, they’ll also target petunia flowers, ripping unsightly holes in them.
Since cutworms mainly feed at night, you may never see these creepy crawlers, but you’ll see the damage they do!
How To Repel Cutworms From Petunia Plants
The only good thing about variegated cutworms is that they are large enough to see. On cloudy days you can see these pests munching on petunia plants.
To keep cutworms from devouring petunia plants, try some of these suggestions:
- Physically remove them: During the day, rake through the soil or mulch under petunia plants. This will expose cutworms which you can then dispose of.
- Disrupt lifecycle: In the summer and fall, pull all the weeds from around petunias. This eliminates places where the cutworm moth can lay eggs for next year’s generation.
- Beneficial nematodes: According to the University of California, Steinernema carpocapsae nematodes are effective at controlling variegated cutworms.
You can purchase these beneficial nematodes online, like these Natures Good Guys Live Beneficial Nematodes. Always read the directions on the label before using this treatment.
Leafminers Prefer Feeding On Petunia Leaves
There are many kinds of leafminers, but the main species that eat petunias are the serpentine leafminer.
Both the adult leafminer and the larvae will feed on petunia leaves. The damage done by each stage will be different.
Leafminers are most active during warm weather, but damage can happen during the entire blooming season of petunias, which lasts from spring until the first frost. This is because the lifecycle of leafminers is so short that continuous generations are happening all year long.
Damage from leafminers is very distinctive compared to damage by other insects. Check for these telltale signs of leafminer damage:
- White trails on leaves: Eggs are deposited inside leaves. When they hatch, the larvae will feed between the upper and lower surface of the leaves, creating ‘mines.’ These mines will leave twisting trails of white-grey damage on the leaves.
- White speckles: When adult leafminers feed on leaves and flowers, they puncture the area to suck out the sap. The holes left behind will turn white, giving the flower or leaf a speckled appearance.
- Leaf drop: If populations are high, leafminer mines can damage leaves enough to make them drop early.
How To Stop Leafminers From Mining Petunia Leaves
Leafminers rarely do enough damage to petunias to kill the entire plant. However, the damage they do can be unsightly.
Here are some suggestions for controlling leafminers on petunias:
- Water adequately: Like spider mites, leafminers will seize upon plants that are struggling. Keep your petunias watered and give them plenty of sunshine.
- Clip off affected foliage: Damaged leaves can be clipped from the plant and disposed of, removing the larvae.
- Avoid insecticides: Under normal circumstances, leafminers are controlled by natural enemies. Using insecticides can eliminate these enemies, allowing leafminers to flourish.
Aphids Love Petunia Leaf Sap
Aphids are very tiny insect pests that use sucking mouth parts to zap the sap from petunia leaves. The most common species to prey on petunias are green peach aphid and oleander aphid, but others may be present.
Damage from aphids is rarely severe enough to harm the whole plant, but identifying the damage early can prevent further harm.
Aphids are most active during the hottest time of the year, but can still cause damage in spring and early fall.
Look for these signs of aphid damage to your petunias:
- Leaf curl: While feeding, some aphid species can inject a toxin into petunia leaves that will cause them to curl. This makes it harder for predators to locate aphids.
- Yellow leaves: A high population of aphids feeding on petunia leaves will eventually turn them yellow.
- Sooty mold fungus: Look for black spots on the leaves. This is a sooty mold fungus that grows on the honeydew produced by aphids while they feed.
You may also notice an increased population of ants when aphid populations are high. Ants will protect aphids from predators and, in exchange, they feed on the honeydew produced by the aphids.
There are many reasons aphids may be attracted to your garden, which you can read more by checking that link out!
How To Repel Aphids From Petunia Plants
If you’re seeing signs of leaf curl or yellow leaves, this means the aphid population is getting a little too high for comfort.
It’s best to identify aphids sooner rather than later. Once leaves curl, it can be incredibly difficult to get rid of these pesky petunia eaters.
To control aphids, try some of the below suggestions:
- Control ants: Similar to whiteflies, minimizing the ant population will open aphids up to natural predators. Consider using bait traps to get rid of ants.
- Spray the underside of leaves: Use a garden hose to spray the underside of leaves. This will remove aphids from petunia leaves. They cannot climb back up the plant.
- Use aluminum pie plates: According to Clemson University, reflective materials can help control aphid populations. Cut a hole in an aluminum pie pan and place it at the base of the petunia plant.
Alternatively, you can use reflective mulch. The mulch comes in large bundles, so if you only have a few petunia plants, aluminum pie pans are more practical.
You can also use specific scents that aphids hate to repel them in the future!
Universal Pest Deterrents For Petunias
Every pest is going to be a little different. The best practice for managing aphids will not work with leafminers.
However, there are a few deterrent methods that work universally on all insect petunia pests.
One universal way to repel insects from petunias is to plant things that will attract beneficial predators. According to a journal article in Florida Entomologist, sunflowers are a fantastic plant to grow to attract beneficial predatory insects that can naturally take care of insect pests.
Another universal deterrent is to inspect petunias thoroughly before purchase. Check the flower petals, stems, and leaves to ensure they look healthy and green. When planting from seed, be extra vigilant when buds appear.
That’s All For Now!
No landscape is complete without a colorful collection of petunia plants. These beautiful flowers are the target of many pests, but with a little effort, these pests can be repelled.
Now, for a quick recap.
The 7 bugs and insects that LOVE eating petunias include:
- Cyclamen mites
- Spider mites
- Variegated cutworms
If one of the above pests or something else is tearing through your petunias with no end in sight, you can always reach out to a professional near you using our nationwide pest control finder.
Dedryver, C.-A., Ralec, A. L., & Fabre, F. (2010, June-July). The conflicting relationships between aphids and men: A review of aphid damage and control strategies. Biology Reports, 333(6-7), 539-553.
Johnson, E. T., Berhow, M. A., & Dowd, P. F. (2008). Colored and White Sectors From Star-Patterned Petunia Flowers Display Differential Resistance to Corn Earworm and Cabbage Looper Larvae. Journal of Chemical Ecology, 34(757).
Jones, G. A., & Gillett, J. L. (2005). Intercropping With Sunflowers To Attract Beneficial Insects In Organic Agriculture. Florida Entomologist, 88(1), 91-96.
Kessler, D., Diezel, C., Clark, D. G., Colquhoun, T. A., & Baldwin, I. T. (2012, November 23). Petunia flowers solve the defence/apparency dilemma of pollinator attraction by deploying complex floral blends. Ecology Letters, 16(3), 299-306.
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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