What Causes Holes in Hosta Leaves

Nothing beats the appealing sight of hostas with their broad, lush, and variegated foliage. Although they’re hardy herbaceous plants, hostas sometimes experience damage, including having holes in their leaves. But what causes these holes in hosta leaves?

Various factors cause holes in hosta leaves, including invasion by snails, slugs, pathogens, or insects. Some weather conditions also cause hosta leaf damage. Thus, it’s essential to know what’s eating your hostas and prevent or control it.

You wouldn’t want to lose all your hostas to leaf damage, so it’s essential to identify what’s ailing your plants as soon as possible. This article will discuss the causes, symptoms, and remedies of holes in hosta leaves. So, read on to learn more about the causes of holes in hosta leaves!

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Reasons Why Your Hosta Leaves Have Holes

Even though hostas are attractive flowering plants, they may not always look appealing, as their beautiful foliage also invites pests and pathogens. These organisms feed on hostas’ lush leaves and stalks, causing severe damage.

Hence, holes in hosta leaves are one of the common problems that hosta farmers in the US face every growing season.

So, if you notice that the leaves of your hostas have ragged edges and tiny holes, know that your plants are under attack.

But, what are the main reasons why hosta leaves get holes?

Slugs and Snails

Slugs and snails are the main culprits of holes in hosta leaves. The two types of mollusks love nibbling on the fleshy leaves of these ornamental plants at night. According to the Missouri Botanical Garden, you may not know that snails or slugs have invaded your hostas until you notice some unusual signs.

You’ll know that slugs or snails are eating your hostas when you notice:

Irregularly shaped holes on the hosta leaves – Snails and slugs feed on the succulent parts of your hosta plant, including the leaf edges and veins. Slugs create ragged holes in the hosta leaves using their file-like mouthparts. The leaf damage is not only ugly but detrimental to young hostas.
Slimy trails: Slugs and snails don’t hide their tracks since they always leave slimy trails behind. These are mucous remains that the mollusks use to move across plants and along the ground.

The Chicago Tribune acknowledges that slugs and snails are a real menace. And they usually occur when the temperatures are above 50°F (10°C) – in spring and summer. Plus, they love it when hostas – and the soil, have a lot of water after rainfall or watering.

Since the mollusks love damp conditions, they’ll invade your garden if you’ve used a heavy mulch cover for your hostas as the soil will retain moisture. Moreover, they’ll take cover under debris, the lower leaves, and densely populated hosta plants.

Diseases

Snails and slugs aren’t always to blame for your damaged hosta leaves. Your plants could have holes due to attack by disease-causing pathogens. For instance, Colletotrichum fungi cause fungal disease in hostas called Anthracnose.

Like mollusks, these fungi usually attack hostas with high temperatures and moist conditions. And the disease damages the leaves by causing numerous black spots. Eventually, the leaves become tattered when the centers of these spots weaken.

Foliar nematodes also cause leaf damage by feeding on hosta leaf tissues. These microscopic worms love the soft tissues in between the leaf veins. Moreover, they lay their eggs within the leaves and then exit them after damaging them.

Nematodes also infest hostas when the leaves are wet. These tiny roundworms form light green or yellow streaks on the affected parts. These stripes may also become weak, causing V-shaped holes in the leaves. Furthermore, the damaged leaves become necrotic and fall off.

Insects

Several insects love eating the fleshy hosta leaves. These bugs feed on different parts of the leaves and have varied feeding behaviors. However, all of them cause damage you’ll notice from the ragged or tattered holes on your hosta leaves.

These leaf-eating insects include:

Cutworms: These larvae damage plants by cutting through various parts. They enjoy feeding on soft tissues in the leaves, stems, buds, and flowers. In Minnesota, several cutworm species are a problem for farmers. The variegated cutworms eat young (curled) hosta leaves after dusk, leaving ugly shapes.
Blister beetles: These bugs also love feeding on hosta leaves, causing immense damage. In Florida, for example, about 26 species of blister beetles exist. Apart from feeding on plants, these insects threaten humans since their hemolymph (blood-like fluid) produces blisters on human skin.
Grasshoppers: They feed on hosta plants in the same ways as black vine beetles. Hence, it can be difficult to tell which specific bug is causing holes in your hostas unless you catch them doing it.
Black vine beetles: These bugs feed on hosta leaves from the margins towards the center. So, you’ll detect their presence if your hosta leaves have irregular notches. Black vine beetles are nocturnal feeders and immediately fall to the ground if caught.

Weather Conditions

Occasionally, your hosta leaves could have holes due to weather conditions. Hail is the most common element that damages hosta leaves as it affects the tender tissues between the veins. After a hailstorm, the leaves get holes with jagged edges, appearing torn.

Hosta leaves are also susceptible to frost damage. Frost damages the actively growing tissues in young leaves and shoots. Hence, the leaves will have pleated slices of the missing tissues when they continue growing and expanding. Eventually, the margins of these holes will turn brown, and the leaves will appear disfigured.

How Do You Prevent Holes in Hosta Leaves?

You can prevent holes in hosta leaves by protecting them from pests and diseases. Hence, it’s essential not to create conditions that will attract these invaders. For instance, many problems prefer a moist (or damp) environment.

Here are several ways of protecting your hosta leaves from attack by pests and disease-causing pathogens:

Avoid overwatering your hostas. The moisture in the soil is attractive to some bugs and snails, which will eat your hostas.
Remove heavy debris or mulch covering. To prevent snails or slugs from attacking your hostas.
Avoid irrigating your hostas in the evening. Watering at night will create a perfect environment for slug or snail infestation as they seek cool and damp places to feed.
Grow hostas in containers, making it harder for snails and slugs to invade your hostas. Also, place the containers on a large saucer plate, and you can apply plant-protection glue to the pot to keep snails and slugs away.
Use crushed eggshells, copper tape (or rings), or diatomaceous earth near your hosta growing beds – these will create a prickly barrier for slugs and snails since they have soft bodies.
Use horticultural oil to repel bugs from your hosta plants. You can plant repellent herbs in your garden, including rosemary and fennel.
Attract birds such as house wrens to control bugs in your garden. You can set up some birdhouses with birdseed to lure the birds.
Water your hostas in the morning. Ensure that the soil (and hosta leaves) aren’t wet by evening since most pests are nocturnal feeders and are attracted to damp environments.
Cover your hostas with a fabric sheet if your region expects hail or out-of-season frost. However, the material shouldn’t be in contact with the plants, so prop it up with boards, stakes, or sticks.
Space your hostas when planting. To prevent crowding, moisture retention, and attack by pathogens that cause fungal diseases, such as Anthracnose.

How To Treat Holes in Hosta Leaves

Prevention is always the best remedy. However, treatment could be the only option if some pests have invaded your plants. Therefore, you can treat holes in your hosta leaves using several methods, including:

Apply Insecticides

For example, you can use carbaryl dust (Sevin) to control bugs like grasshoppers. However, since exposure to such chemicals can cause health problems, you can use a safer alternative.

For instance, mix liquid soap with neem or tea tree oil to spray your hosta leaves. Some people also use garlic sprays or insecticidal soaps to deal with bugs.

Use Biological Controls

If you don’t want to use chemicals to kill insects or other pests attacking your hostas, introduce nematodes that feed on them. For instance, the Heterorhabditis species are ideal for controlling black vine beetles. You can also attract animals that feed on snails and slugs into your garden, including birds, chickens, and ground beetles.

Use Beer Traps To Catch Snails and Slugs

Place steep-sided containers with a beer in a small hole in your garden and cover them with lids. Slugs and snails can’t resist the lure of yeast and will seek out your beer trap to their demise. Cut one or two openings where snails and slugs will enter (and drown) since they cannot exit the trap once they enter.

Remove Snails, Slugs, and Bugs Manually

If you don’t mind holding the pests, get your flashlight at night and inspect your hostas for bugs and slimy creatures. Many plant pests use the cover of darkness to invade your plants when they are safe from predators and the effects of the sun. You may then hand-pick them and put them in soapy water or trash bags.

Final Thoughts

Hostas are attractive perennial plants that ensure your garden or indoor space is never dull. However, pest infestation, diseases, and some weather conditions can damage plants by creating holes in the leaves. Therefore, taking preventive measures is advisable, including setting up barriers to protect your hostas from such problems.