You love having Zinnias in your garden. They are easy to grow and produce stunning colorful flowers. However, one day you discover that something has been eating them, and you will be left asking yourself ‘what is eating my zinnia leaves?’.
There are many things that may eat your zinnia leaves. These include insects, animals, and bacteria. The good news is that once you identify the pest, you can take steps to protect your plants.
Leaf spot will cause holes in your zinnia leaves. Fungal leaf spot is caused by the Alternaria fungus. Initially, you’ll notice red or purple lesions on the leaves.
These spots will turn gray or tan over time. As the fungus eats the leaf, these lesions become holes in the leaves. It can also affect the flowers.
Bacterial leaf spot looks a bit different. It starts as small circular spots. They then develop a yellow border around them. They will grow and merge with each other, creating bigger spots.
Then, the spots will turn black and eventually create holes in the leaf as the tissue dies.
Treating Leaf Spot
Mild fungal leaf spot infection can be treated with a copper fungicide. If the infection is severe, this will not be effective. Continue treating once a week until the spots disappear.
Severe fungal leaf spot and bacterial leaf spot can’t be treated. You’ll need to destroy the plant to prevent the disease from spreading.
You can prevent fungal leaf spot by watering your zinnias in the morning. Do not wet the leaves, because this provides an environment for leaf spot to grow.
Aphids are the enemy of many plants, including zinnia, and they can also cause Beech hedges to die as well. They will punch holes in the leaves to feed on the plant sap. A few aphids aren’t harmful, but they can weaken your plants in large numbers.
They reproduce quickly, so it’s important to eradicate them early before they multiply.
Most aphids are green, but the black aphid loves zinnia leaves. They are small, but you can spot them if you look closely. They have pear-shaped bodies and long antennae.
You may also spot a sticky sap on the leaves. This is the waste the aphids leave behind.
Getting Rid of Aphids
If you only have a few aphids, you may be able to remove them with a water hose. This will dislodge them from your zinnias.
Neem oil can control aphids, but it must come into contact with them to be effective.
You can also use a simple soap and water mixture. Combine 1 quart of water, a teaspoon of dish liquid, and a dash of cayenne pepper. Spray this mixture on the zinnias every 2 to 3 days for 2 weeks.
Several types of caterpillars love to feed on zinnia leaves. These include Leafrollers, Cabbage looper larvae, Armyworms and Cutworms.
Leafrollers are yellowish-brown with black-colored heads. They will eat both the leaves and flowers of the zinnia, consuming blooms before they have a chance to flower.
Cabbage looper larvae are light green in color. They have white lines running along each side of their body. Young loopers will feed on the underside of the leaves. Mature loopers will consume the leaves and flowers.
Army or cutworms begin as small green worms. They will turn black, brown, or gray once they mature. These caterpillars will skeletonize the leaves, leaving the veins behind.
Different types of caterpillars have the same basic effects. They will defoliate your plant, and eat your zinnia blooms as well. They are one of the most dangerous pests to your plants because they can quickly kill your zinnias.
Learn how Caterpillars can cause honeysuckle to go woody here.
One way to control caterpillars is with Bacillus thuringiensis. This is a naturally occurring bacterium that is fatal to caterpillars. When they ingest it, it paralyzes their digestive system. This causes death.
Another method is to remove them by hand. You should wear gloves to do this because some caterpillars can sting. Once you’ve removed them, you can throw them into a bucket of soapy water to drown them.
If you want to let them live to turn into moths and butterflies, you can relocate them away from your zinnias and other plants.
Slugs may not be the first pest that comes to mind, but they also eat zinnia leaves. If you find holes in your zinnia leaves in the morning, slugs might be the culprit.
Slugs create ragged, irregular holes in the leaves. These holes will also cross leaf veins.
They leave a shiny slime trail behind. If you notice this on your plants, you probably have slugs feasting on your zinnias during the night.
Solving a Slug Problem
One way to get rid of slugs on your zinnias is to manually remove them. You’ll need to visit your zinnias at night. Look for any slugs on or near your plants.
Remove them from the plant. You can throw them in a bucket of soapy water to kill them. Salt will also work.
Another method is to create slug traps. Wet newspaper and shallow bowls of beer create a hazard for the slug, allowing you to trap them. You can then dispose of them using the methods above.
Japanese beetles are a common pest that eats other plants like Geraniums as well as zinnias. Instead of eating holes in the leaf, the beetle will eat nearly the entire leaf, leaving only the veins. The ravaged leaf will look similar to lace.
They occur between late June to August. They can also chew holes in your zinnia blossoms.
They are flying insects. Their body is a bright iridescent green, and their wing cover is copper.
Ridding Your Zinnias of Japanese Beetles
One way to get rid of Japanese beetles is to use dish soap. Mix 4 tablespoons of soap in 1 quart of water. Spray on any beetles you see to kill them.
You can also use a pyrethrin-based insecticide or neem oil. These are most effective if used at the first sign of the beetles.
Earwigs are active from late June into the fall. They have pincers on the end of their abdomen, which makes them easy to recognize. They are reddish-brown and have short wings.
They chew irregularly shaped holes in the leaves, and can also attack zinnia blooms. They are more active at night than during the day.
Should You Get Rid of Ear Wigs?
Earwigs typically feed on dead plant matter. They will also eat other insects, including aphids, grubs, and armyworms. This can make them beneficial to your zinnias.
However, if you have a large population of earwigs, they can feed on live plants. This is because their preferred food sources have become scarce.
To prevent earwigs from damaging your plants, you can apply petroleum jelly to the plant stems. Earwigs will not climb up the plant when it is applied.
You can also use oil pit traps. Combine soy sauce and olive oil in equal parts. Place it in a small container with a lid. Punch holes in the container, near the lid. The holes should be large enough for the earwigs to get into the container. Bury the container in the soil, leaving the holes at or slightly above ground level.
The soy sauce attracts the earwigs, and the oil keeps them from escaping. Change the mixture as needed.
Deer can also make a meal of zinnias. If they are the cause, the entire leaf will probably be missing, leaving only a petiole and stem. They may also take a large portion of the leaf.
They will leave ragged edges on the leaves. You may also notice deer prints or droppings near your zinnias.
Another sign is that the damage happens suddenly, typically overnight.
There are a few ways to keep deer out of your garden. One option is a fence. Deer are graceful jumpers, so the fence needs to be at least 8 feet tall.
Another option is deer repellant. These can be created with ingredients including eggs, blood, and soap. They must be applied frequently to be effective.
Rabbits can also wreak havoc on your zinnias. Like deer, they will eat a large portion of the leaf or all of it, leaving the petiole and the stem. However, unlike deer, rabbits leave a clean-cut angle.
You can also look for rabbit droppings and footprints. Like deer, rabbits commonly feed at night.
How to Keep Rabbits Out of Your Garden
Like deer, a fence can be effective for keeping rabbits from eating your zinnias. To do this, you’ll need to use chicken wire. It must be buried at least 6 inches into the ground because rabbits are avid diggers.
You can also create a homemade rabbit repellent. To do this, mix 2 tablespoons of cayenne pepper, 2 tablespoons of garlic powder, 1 teaspoon of Castile soap, and five cups of water.
Pour into a spray bottle, and apply it to your zinnias. This should repel the rabbits due to the smell.
As you can see, there are a lot of things that can eat your zinnia leaves. The good news is that most of them can be controlled or eliminated. Leaf spot disease, insects, and animals are all potential culprits.
To determine which one is affecting your zinnias, look for signs of the pest and the damage to the leaves. Once you know what is making a meal out of your plants, you can take steps to fix the issue.