Even the best gardeners occasionally experience leaf rot when their plants are at their most attractive. It takes some detective effort to identify the perpetrators that are munching holes in your plant’s leaves, but typical offenders offer plenty of hints. You can identify the culprits and stop their hole-making by examining the holes that have been made in your plants. It can be helpful to recognize these four typical leaf holes:
1. Extensive, erratic holes in leaves.
Slugs and snails are the best pests for chewing holes in leaves. Usually, rather than near the borders of leaves, these slimy critters consume holes that are closer to the center of the leaves. They leave behind big, crooked leaf holes.
Slug and snail holes can have a variety of shapes, although they generally have smooth edges. The last piece of proof that slugs and snails are to blame is trails of slippery, silvery slug or snail mucus.
Many kinds of plants, such as basil, hosta, hibiscus, cabbage, cucumbers, lettuce, tomatoes, and peppers, frequently have slug and snail leaf holes. Most of the damage these pests cause happens at night. Your hunch will become more accurate with a flashlight-assisted evening stroll.
2. Leaf edges have both large and small holes.
Other pests aren’t as fussy, however slugs and snails start eating toward the cores of the leaves. Caterpillars often begin their feasts around the leaf edge and chew holes in the entire leaf.
Although some caterpillar holes resemble slug holes, these pests don’t leave behind mucus trails. Instead, you’ll see a lot of dark feces. Caterpillars that feed on leaves at night can be seen hidden on the undersides of leaves during the day.
Caterpillars range in size from inchworm-like cabbage loopers that bite holes in plant leaves to 4-inch tomato hornworms. Many plants, such as roses, hydrangeas, tomatoes, peppers, broccoli, and cabbage, are favorites of caterpillars.
3. Holes in the leaves that resemble skeletons.
It is clear who is to blame because some leaf holes are distinctive. The holes that form when Japanese beetles begin eating plant leaves resemble those of other pests. However, the more time these ravenous insects spend feeding, the more recognizable their leaf holes become.
Japanese beetles consume the veins of leaves, leaving behind a lace-like skeleton. On warm, sunny days, they frequently assemble in huge numbers as they feed. Plants are frequently entirely stripped of their leaves, leaving only the leaf skeletons.
Over 300 different plant species are consumed by Japanese beetles. Numerous plants, including hydrangeas, roses, and hibiscus, have their skeletonized leaf holes. Along with eating holes in plant leaves, these parasites frequently eat holes in flower petals.
4. The leaves include a few tiny “shot holes.”
Japanese beetles leave behind damage that is almost as recognizable, although these holes have a very different appearance. Flea bugs of several species bore small holes in plant leaves that resemble shotgun bursts in miniature.
Leaf holes made by flea beetles have a windowpane appearance because these parasites don’t entirely gnaw through the leaf. Many different kinds of plants, including roses, hydrangeas, broccoli, cabbage, kale, tomatoes, peppers, eggplants, and even fragrant mint, are attacked by flea beetles and develop holes.
Cucumber beetles and other microscopic insects are responsible for similar-appearing leaf holes. The harm is more severe the longer they devour plant leaves. However, cucumber bugs normally only cause leaf holes in a few types of plants, such cucumbers and squash.
Beetles, caterpillars, earwigs, or slugs may be to blame if you notice holes or ragged portions of leaves missing and the damage has been happening gradually with a little feeding each night. Look for any remnants of these four to help you identify between them.
Caterpillars deposit their waste under the leaves or close to the damage. Droppings like tiny “pellets.” Certain caterpillars produce webbing. Damage can range from a few small holes in the leaves to the elimination of substantial amounts of the leaf. Cutworm caterpillars consume stems and leaves at night. Look for the curled-up caterpillars among plant stems close below the soil’s surface throughout the day.
Beetles frequently evade detection by falling to the ground and are less likely to leave droppings. As you search for them, they fall in reaction to the shifting of the leaves. Keep a close eye out for signals like egg clusters and small larvae under the leaves. Look for information on the plant that is being chewed to find out what insect pests are frequently linked with it. Caterpillars and beetles of many different varieties and sizes can be found in gardens.
The European earwig, which is common in New England gardens, can harm fragile fruit, corn silk, and young vegetables. The leaves of several varieties of vegetable plants will have numerous holes chewed in them. Older leaves typically have bitten edges, but younger leaves may have holes all over the leaf. Earwigs frequently gnaw on leaves that appear ragged.
As they feed, slugs exude a layer of slime that dries into a glossy trail. The slime aids in preventing their bodies from drying up, and it frequently leaves a deposit where the slug has crawled.
Look for pests at dusk or at night using a flashlight to conduct further research. Numerous earwigs, slugs, and beetles, in particular, feed at night and conceal during the day. In home vegetable gardens, handpicking caterpillars, beetles, and slugs and dumping them into soapy water can be helpful. Use shallow cans baited with fish oil or a dab of bacon grease in vegetable oil to catch earwigs.
Damage Caused by Piercing-sucking Insects
Look closely for tiny, soft-bodied insects in groups along the stems or under the foliage of plants with wilted, drooping leaves or small yellow patches. Squash bugs, whiteflies, and aphids all have mouthparts that resemble miniature straws. They take in nourishing plant liquids by sticking their mouthparts into a leaf or stem. This procedure leaves behind yellow flecks or patches. Whiteflies and aphids don’t get much bigger than 1/8 in length. Seek out a sticky substance known as “honeydew” on plants beneath or nearby where they feed. This residue frequently turns sooty from mold.
Squash bugs hatch from clusters of bronze-colored eggs that are typically placed on the underside of squash leaves. At first just about 1/8 long, grey, and soft, they develop into approximately 3/4-sized, brown, hard-shelled adults. While squash bugs travel around on the plant, frequently under the leaves, aphids and whiteflies feed primarily in one location.
Leaf-mining, Root-feeding and Stem-feeding Damage
Leaf miners are visible as winding, tan-colored spots on the leaves of Swiss chard, beets, and spinach. These minuscule fly larvae burrow between the leaf’s surfaces and form the splotchy tracks known as “mines. If a mine is still active, you can remove the top layer and find the tiny white maggot. The adult fly lays its eggs on a leaf’s surface, and the eggs hatch into larvae that burrow into the leaf’s inner tissue to feed.
Do the cabbage seedlings you have wilt? The cabbage root maggot fly lays its eggs close to the host plant (or seed), and its larvae emerge from the soil and burrow into the roots or seeds. It is closely related to onion and seed corn maggot flies. Broccoli, cabbage, cauliflower, radishes, and other cabbage family members are among the plants that are impacted, along with onions, vine crops (cucumbers, squash, pumpkins, melons, and gourds), and corn, pea, and bean seeds. The adults resemble tiny houseflies in size. The harm is caused by the larvae, or maggots, as they feed and burrow. Damage can result in wilting, poor germination, unattractive radishes, and rotting onions.
When cucumber seedlings wilt, become yellow, and maybe die, they may have Erwinia tracheiphila, a bacterial wilt disease that is spread by cucumber beetles. Look for small, 1/4-long beetles with yellow and black stripes or black spots that are eating the tender leaves of vine crops (cucurbits). Massachusetts is home to both the striped and the spotted cucumber beetle. Their harm includes spreading the wilt illness and feasting on stems, leaves, and roots. Most at risk are seedlings with less than five leaves.
The leaves of squash plants may start to wilt when they start to bear fruit. Look for excrement, also known as feces, along the stem from the wilted leaf “Frass is the sawdust-like residue that the insect feasting inside the stem left behind. Make a lengthwise slit in the stem close to the frass and look inside to find the huge, cream-colored caterpillar. After removing the caterpillar, add several inches of soil to the damaged area of the stem to promote roots. On squash plants during the day, keep an eye out for the orange and black adult moth, which soars like a little hummingbird. The moth deposits minuscule, rust-colored eggs on leaves and along stems.
After determining the source of the damage, think about how you will handle the situation. You can either let natural enemies control the insect population or manually wash or remove the pests off the plants, depending on the extent of the damage. To protect crops from insects like flies, beetles, butterflies, and moths that lay eggs for caterpillars, consider using lightweight row coverings. For vine crops and seedlings of plants in the cabbage family, row coverings used at planting time frequently offer the best protection.
Products derived from natural components that contain Bacillus thuringiensis (Bt), neem (azadarachtin), or spinosad can be used to control some insects and caterpillars in vegetable gardens. Neem, various oil products, and insecticidal soaps may work well as both pesticides and/or deterrents for soft-bodied insects. Insects in their early, immature stages are always more susceptible to treatment than those in their later stages. Choose a product that is labeled for both the insect and the crop after carefully reading the labels.
Dusk is a good time to treat for active pests if you choose to apply a pesticide for three reasons:
- Pollinators and helpful insects are less likely to be active.
- Organic insecticides’ active components deteriorate more slowly in the absence of sunshine.
- At dusk, the wind frequently slows down, reducing spray drift.
Japanese Beetle Prevention
Early in the morning, when the insects are least active, begin by shaking the insects off the plants. Spray down the plants with a homemade insecticidal soap once they have temporarily left. Use one tablespoon of dish detergent, one cup of vegetable oil, one quart of water, and one cup of rubbing alcohol to make a fantastic homemade bug spray for vegetable plants. Apply this spray in the morning for best effects, and be prepared to water the plants again if they begin to droop after the treatment.
Tarnished Plant Bug Prevention
By keeping your garden clear of weeds throughout the spring, at least to the extent practicable, you can prevent attracting these bugs in the first place. By doing this, you’ll reduce the number of locations for bugs to hide and lessen their appeal to your garden. But if you have a tarnished plant bug issue, find the nymphs and spray them with neem oil to get rid of it. Finally, encouraging natural predators of these insects is one of your greatest chances because they will do a large portion of your work for you.
Flea Beetle Prevention
Garlic-based products work well as natural insect repellents for flea beetles. A head of garlic, one tablespoon of dish soap without bleach, two tablespoons of vegetable oil, and two cups of water are the ingredients for this cure. Peel the garlic, then blend it with the water and oil to create the spray. Before straining the mixture, let it stand the following day. Add the soap and carefully combine. Simply pour it into a spray bottle after that, then use that to cover the diseased plants.
There are various techniques you might use to keep caterpillars away. The first step is to support native predators that will consume the caterpillars and eliminate them for you. Another approach is to mist the plants with a neem oil and water mixture.
Finally, you may attempt assembling a DIY chili spray. Blend three and a half ounces of dried chiles to produce this spray. Before adding half a gallon of cold water and a few drops of dish soap, add this powder to a half gallon of boiling water and let it boil for five minutes. Spray the caterpillars with this solution every morning until you stop seeing them.
What consumes plant leaf holes?
Snails and slugs are considered members of the “gastropods” order of animals. That scientific term roughly translates as “stomach-foot.” You will realize the term fits them perfectly if these ravenous bugs attack your garden. Visit your garden at night with a flashlight if you discover holes in the leaves but no bugs. Slugs and snails carry out their unpleasant tasks then.
Many plant species, including hibiscus, hosta, basil, cabbage, tomatoes, lettuce, cucumbers, and pepper plants, have slugs and snails that gnaw holes in their leaves. These hints are provided by slug and snail leaf holes:
- Large and atypically shaped holes are present.
- Edges of holes are often smooth.
- Instead of the leaf edges, holes show up there.
- Silvery slime trails lead to and from the plants.
Insecticides do not work to control slugs and snails since they are not insects. You can get rid of slugs and snailsand stop the damage fast with Corry’s Slug & Snail Killer ready-to-use pellets. The treated areas are instantly accessible to people and animals.
How can I remove bugs from my outdoor plants?
Nothing brings a gardener greater satisfaction than a patch full of gorgeous flowers or produce. Our flower and vegetable beds are being used as a salad bar by numerous garden insects, which is a problem. But by using these straightforward, natural, and reasonably priced techniques to deal with garden insect pests, you may still have a lovely garden without resorting to pesticides. My family and I use them at home and at our wholesale plant business, so I know they are effective.
Start with “Clean Soil
Pest garden insects can actually be discouraged by good soil. But getting ready takes time. This approach is really effective for me:
- When the growing season starts, turn organic stuff like compost into the soil first. By including natural components and pest-repelling substances, this will help keep your soil clean.
- After tilling, cover your garden for six months with cardboard or black plastic. The majority of garden pests, including their eggs, weeds, parasites, and a variety of other dangerous germs, will be killed by the heat that accumulates underneath it.
- Lightly cultivate the soil after removing the plastic. You are now prepared to plant.
Buy Disease and Pest-Resistant Seeds
Pests and illnesses are simpler to prevent than to eradicate after they have invaded your garden. Look for letters like V, F, N, or T after a seed’s name when browsing through a seed catalog; these letters denote the issues to which the seed is most resilient. The letters V and F stand for the tomato illnesses verticillium and fusarium, respectively; N is for nematodes; and T stands for the tobacco mosaic virus, which causes the plant’s leaves to wilt and turn yellow as well as causing harm to the roots. Look into the top online retailers for seeds and plants.
Selectively and Aggressively Thin Out Plants
This is crucial because illness is more prone to spread among small, frail seedlings. They might then transmit the issue to healthy plants. So make sure to remove any branches and dead shoots that are obstructing ventilation. For plants to breathe and be healthy, proper air circulation is essential.
Water Plants in the Early Morning
Why? Well, the primary function of water in plants is to support photosynthesis, which takes place during the day. Additionally, watering later in the day will result in damp leaves during the chilly nighttime, which is excellent for the growth of fungus and other illnesses. When you water, make sure to drench the roots rather than the foliage. Hoses that drip or soak are a wise investment. Use these recommendations to save water in your garden.
Your plants must compete with weeds for scarce resources like water, nutrients, and sunshine. Additionally, they frequently host parasites and pest garden insects. Make sure to totally remove weeds and their roots from the ground. Here are some tips for defeating weeds.
Keep your Garden Clean
Because decaying plant waste serves as a perfect habitat for fungus, garden bugs, and diseases, it is crucial to remove faded blossoms, fallen leaves, and weeds. Every time you enter your garden, bring a small pail or bucket with you and use it to gather garden waste.
Use Insect Traps
Almost all garden centers sell yellow “adhesive cards. They will capture a lot of garden bugs that are scurrying around your garden if they are placed on the ground and in between the shoots or branches of plants. To learn how to distinguish between beneficial and harmful garden bugs, get in touch with your neighborhood garden center or county extension agent.
Add Beneficial Insects
Ladybugs and other insects can be quite helpful in the fight against garden insect problems. They consume mites, aphids, and the eggs and larvae of numerous harmful insects. Praying mantises, lacewings, and parasitic wasps are some other advantageous garden pests. The majority of helpful insects are available from major horticulture supply firms. The quantity you’ll require for your garden can be determined with the help of your county extension agent. One crucial rule is to wait 10 days before releasing these insects without using any insecticides.
Practice Crop Rotation
The exact garden pests that attack a crop will remain in the area, waiting for the following spring’s planting, if you cultivate it in the same spot every year. Crop rotation also prevents the soil from losing essential nutrients. For instance, where you previously grew tomatoes, corn, or squash, plant legumes (which add nitrogen to the soil) (which deplete nitrogen in the soil).