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Dahlias are very pretty and easy to care for plants that bloom in clusters from early summer to late fall. However, finding dahlia insect pests on your prized plants is a frustrating and disappointing experience. Read on to learn about insects that like dahlias, and about treating pests that affect dahlias.
With their vibrant, diverse blooms in stunning colors, dahlias bring so much beauty to summer gardens. However, they also attract a troublesome cast of hungry insect pests. Nothing spoils the joy of growing dahlias faster than finding chewed petals, stunted buds and deformed foliage caused by voracious bugs.
As a longtime dahlia devotee, I’ve battled all the usual culprits including thrips, Japanese beetles, earwigs, cucumber beetles and more. If left unchecked, these relentless little bugs can quickly decimate dahlia plants. But over the years I’ve discovered safe, effective organic sprays that protect my dahlias while also benefiting the environment.
In this article, I’ll share my top tips for keeping dahlias pest-free using natural and organic sprays. You’ll learn when and how often to spray along with the best organic ingredients to target common dahlia bugs. With this guide, you can grow flawless, bug-free dahlias without using toxic chemicals! Let’s dive in.
Know Your Dahlia Pests
First, it helps to identify the usual insect troublemakers on dahlias. Learning their appearance, feeding habits and life cycles allows you to better control them. Here are the most common dahlia pests
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Aphids – Tiny, soft-bodied insects that suck sap and coat plants with sticky honeydew They cause curled, stunted new growth
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Thrips – Teensy winged bugs that rasp and feed on plant tissue. They leave behind silver-white scars on buds leaves and blooms.
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Earwigs – Creepy looking insects with pinching appendages that chew ragged holes, usually at night.
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Cucumber beetles – Shiny green and yellow striped beetles that skeletonize foliage while spreading disease.
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Slugs & Snails– Slimy mollusks that chew large, irregular holes in foliage and petals.
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Japanese Beetles – Metallic green beetles that quickly skeletonize leaves and devour flower petals.
Knowing which bugs are munching on your dahlias allows you to choose the best organic sprays to target them. Now let’s look at effective ingredients and products.
Top Organic Sprays for Controlling Dahlia Pests
Here are the safest, most effective options I’ve found for blasting dahlia bugs the natural way:
Insecticidal Soap
Potassium salts of fatty acids that dissolve soft-bodied insects like aphids, mites, whiteflies, leafhoppers, and more on contact. Spray it directly on bugs for quick knockdown. It also disrupts insect feeding. Brands like Safer’s, Garden Safe and Natural Guard make reliable insecticidal soap concentrates that mix with water. Apply weekly as needed.
Neem Oil
Extracted from the seeds of the neem tree, neem oil contains azadirachtin which disrupts insect reproduction and development. Neem oil coats plants with a residue that deters beetles, mites, aphids, caterpillars and other pests from feeding. It’s most effective on young, immature insects. Some brands I like are Bonide and Monterey neem oil.
Pyrethrin
Derived from chrysanthemum flowers, pyrethrins are botanical insecticides that quickly paralyze and knock down most insects they contact by interfering with sodium channels. However, pyrethrins break down quickly in sunlight, so reapply every 5-7 days. Look for pyrethrin concentrates from Safer Brand, Bonide or Monterey to mix as foliar sprays.
Spinosad
A natural bacterium that infects insect nervous systems when ingested. Spinosad is effective for thrip and beetle control, but slower acting than other natural pesticides. It provides 5-7 days of residual pest protection. Products like Monterey Garden Spinosad and Captain Jack’s Deadbug work well.
Diatomaceous Earth (DE)
DE consists of fossilized diatoms with sharp edges that cut into soft-bodied insects like slugs, earwigs, beetle larvae, caterpillars and more. The edges pierce their protective outlayer, causing insects to dry out and die. DE is very safe for mammals and beneficial insects. Just avoid breathing the dust when applying.
Follow all label directions carefully when using pest control products. Pay close attention to required protective gear, dilution rates and plant safety warnings when mixing concentrates. Test new products on a few leaves first to ensure plant safety before spraying the whole plant. Avoid applying horticultural oils and soaps to moisture or heat stressed plants.
When to Spray Dahlias for Maximum Pest Protection
Consistent, timely sprays are key to keeping bugs at bay before they get out of control. Follow this spray schedule for success:
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Early spring – Make a dormant spray of horticultural oil plus lime sulfur and apply to tubers before they sprout. This smothers overwintering pests.
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When shoots first emerge – Hit young growth with insecticidal soap to prevent early aphids, thrips and earwigs.
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Every 7 days from mid-spring onward – Keep plants coated with your pest spray of choice to deter infestations before they take hold. Rotation is important to avoid resistance.
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At the first signs of damage – Such as stippling, leaf notching or flower damage. Pick an organic pesticide that targets the pest and spray ASAP before they spread.
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Before cutting blooms or hosting events – Spray a couple days prior to have gorgeous, perfect pest-free blooms for arrangements and guests.
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After rain or watering – Reapply microbe-based products like spinosad and Bt after moisture as they wash off plants.
How to Apply Pest Sprays to Dahlias Like a Pro
For the best pest control, proper application technique is vital. Here are my top tips:
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Read the label! Follow all instructions for mixing, gear requirements, dilution rates, etc. Carefully measure concentrates.
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Use a pump sprayer and mist setting for thorough, even coverage on all plant surfaces including undersides of leaves.
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Spray early in the morning or evening when wind and temps are low to avoid leaf burn.
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Cover every inch of plants – leaves, stems, buds, blooms, and the surrounding soil. Multiple pressurizations may be needed as you work.
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Add a spreader-sticker like mild eco-friendly dish soap to help spray adhere evenly to waxy, hairy plants.
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Reapply products after rain or watering as most natural pesticides wash off plants easily. Don’t wait for more damage or bugs to reappear!
With the right products, timing and technique, you can easily protect your precious dahlias from ravaging insects without using harsh chemicals. The results will be gorgeous, flourishing plants and armloads of flawless, bright blooms all season long.
Treating Pests that Affect Dahlias
To keep dahlia plants healthy and free of pests, the best thing you can do is take good care of them. Water properly and apply fertilizer carefully according to label directions. Keep dahlia beds free of leaves and other plant matter that slugs, snails, earwigs, and other pests could use to hide. Similarly, limit mulch depth to no more than 3 inches (8 cm. ), especially if you notice silvery slug and snail trails. Keep weeds pulled in the area around your dahlias. Prune any damaged plant parts. Large pests like slugs and caterpillars are easy to remove by hand. Remove the pests and drop them in a bucket of soapy water. Evenings or early mornings are the best times for this task, when slugs and caterpillars are more active. Grab a flashlight and be sure to wear gloves to protect your hands. In some cases, wood ashes and diatomaceous earth create scratchy barriers that keep slugs at bay. If caterpillars remain a major problem, consider using Bacillius thuringenesis (Bt), a natural bacteria. When caterpillars eat the bacteria, the toxins give the pests a deadly tummy ache. (Keep in mind that although caterpillars and slugs have similarities, they are very different pests. Bt won’t help alleviate a slug problem, and wood ashes and diatomaceous earth are unlikely to discourage caterpillars. ) Avoid pesticides, which are dangerous for bees and other beneficial insects. Many pests, including spider mites, aphids, and thrips are easily treated with an insecticidal soap spray. Reapply every week to ten days if you continue to notice pests on your dahlias. Seek out safe alternatives, such as chemical-free slug pellets. Consider ways to attract birds, frogs, and toads to your yard. They’ll do a great job at keeping caterpillars, slugs, and other pests in check.
Bugs Eating My Dahlias!
Below are the most common insect pests affecting dahlia plants in the garden:
- Thrips are thin pests with wings that have fringes. They hurt plants by puncturing the leaves and sucking out the juices. Thrips don’t usually kill dahlias, but they can change how they look by making the leaves stippled, dropping leaves, and slowing growth. Most of the time, pesticides don’t work because pests move so quickly from plant to plant.
- Spider mites: Spider mites are much too small to see with the naked eye. They are about the size of a grain of sand. A magnifying glass can help you find the pests, but most of the time you won’t need one because you’ll be able to tell them apart by the thin webs they make on the leaves. Spider mites are often more apparent during dry, dusty weather.
- Pests like Snails and Slugs—These pests can do a lot of damage to dahlias and other plants. They are easy to spot, though, because they chew big holes in leaves and leave slimy, mucus-filled trails behind them wherever they go.
- Caterpillars are the young stages of moths and butterflies. They don’t make slime, but they do chew holes in leaves like slugs do. Caterpillars often wrap themselves in leaves, and curled and rolled leaves are a sure sign that they have been eating your dahlias.
- Earwigs are small brown bugs with pincers that look like they could hurt you. They’re not as scary as they look, though. The most active time for these dahlia bug pests is at night, when they tend to stay hidden. Keep in mind that pesticides are ill-advised. Even though earwigs aren’t very attractive, they keep aphids and other more dangerous pests in check. Use a roll of newspaper or a short piece of old garden hose to catch them.
- Grasshoppers—Grasshoppers don’t harm dahlias too much, but they do eat the plants’ leaves sometimes. It is safe to get rid of these bugs with nosema locustae.
Dahlias 101 – Spraying
FAQ
How do I keep bugs from eating my dahlias?
What do you spray dahlias with?
Can I spray soapy water on dahlias?
What can I spray on dahlias homemade?
How do I get rid of thrips on my dahlias?
Many pests, including spider mites, aphids, and thrips are easily treated with an insecticidal soap spray. Reapply every week to ten days if you continue to notice pests on your dahlias. Seek out safe alternatives, such as chemical-free slug pellets. Consider ways to attract birds, frogs, and toads to your yard.
How do you get rid of Dahlia insect pests?
Using nosema locustae is a safe way to get rid of these insects. Proper plant care is the best line of defense against dahlia insect pests, as healthy dahlia plants are more pest-resistant. Water properly and apply fertilizer carefully according to label directions.
What insecticides kill dahlias?
Earwigs: Keep your dahlia beds clean and set up traps. Now, let’s dive into some specific insecticides that work wonders on dahlias: Contains: 0.5% Spinosad. Effective Against: Caterpillars, leafminers, thrips. Usage: Mix 4 tablespoons with 1 gallon of water and spray thoroughly. Ideal For: Aphids, leafhoppers, mealybugs, thrips, whiteflies, mites.
Do dahlias attract bugs?
Dahlias, those vibrant and captivating blooms in our gardens, are a joy to behold. However, they often attract a variety of pesky bugs that can dampen their beauty. In this comprehensive guide, I’ll explore the most effective sprays and methods to keep your dahlias bug-free.
How do you get rid of dahlias?
Better yet, use soap and water to forge a homemade bug spray for dahlias. Now, onto slugs, snails, cutworms, and caterpillars. Grab these by surprise in the evening or at the break of dawn and drown them in a bucket of soapy water. For stubborn caterpillars, consider Bonide Thuricide BT Concentrate from Amazon.
What to do if a dahlia plant eats thrips & spider mites?
As for the heat-loving invaders (thrips and spider mites), try routine irrigation. A weekly spray of insecticidal soap or horticultural oil can also turn the tide in your favor. For the audacious aphids, launch strategic attacks with powerful jets of cold water, careful not to harm the dahlia leaves.