Dahlias produce large, multi-petaled blooms that are stunningly beautiful and easy to grow. The only issue these gorgeous flowers have are pests. Some garden pests find dahlias to be very tasty and these pests will devour dahlia leaves, often stripping the plant bare in just one night!
This is exactly what is happening to my dahlias at the moment. What is Eating my Dahlia Leaves?
To find out how to solve the pest problem organically, you will need to become a dahlia detective.
Snails and slugs love the taste of dahlias and they leave a tell-tale slime trail behind when they have been feasting in your flower bed.
If the plant leaves are gone and slime trails are visible, then slugs and/or snails are the problem.
Add a 2-inch (5 cm) layer of rough mulch around the dahlias to prevent these slimy, crawling pests from returning. Roughly crushed eggshells, tree bark, nut hulls, or wood ashes from a fireplace will stop snails and slugs from getting close to your dahlias again.
The organic mulch will also help the soil retain water and will feed the soil as it decomposes.
I found a tiny snail feasting on my dahlia leaves the other day. I just hand-picked them off. You might not see them as they normally hide in damp places during the day, so come back after dark – you’ll most likely see them munching on your dahlia leaves!
Hand Pick Pests
Caterpillars also feast on dahlia leaves and they leave behind a distinct chewing pattern. Leaves will be chewed from the outside edge towards the middle in a side-to-side pattern.
Caterpillars will also roll themselves up in dahlia leaves to hide so they can feast without being detected. Rolled, curled foliage is a dead giveaway that caterpillars have been feasting on your dahlias.
Large pests like snails, slugs, and caterpillars are easy to remove by hand and discard. Evenings or early mornings are the best times for this detective and removal work since this is when snails, slugs, and caterpillars are most active.
While not a major pest of dahlias, grasshoppers do occasionally feed on the plant’s leaves. Using nosema locustae is a safe way to get rid of these pests. Nosema locustae is a naturally-occurring microbe that infects and kills grasshoppers and crickets almost instantly.
The organic nosema locustae are typically sprayed onto grasshopper bait which is then placed around plants.
They are slender pests with fringed wings that cause damage to dahlias by puncturing the leaves and sucking out the juices. Thrips cause leaf drop, leaf stippling, and stunted plant growth.
Thrips move from plant to plant so quickly so you have to act fast to get rid of them before they wipe out your entire dahlia crop.
Blast thrips off with organic Neem oil solution and prevent their return by adding beneficial Lady Bugs to your dahlia bed.
You can find out about DIYing Neem oil spray here in another article, How to get rid of Brown marmorated stink bugs?.