It can be frustrating to find that bugs and critters have taken chunks of your carefully tended plants! But do you know how to stop insects from eating plant leaves using natural methods? Yes, it’s true – it really can be done!
So, if you are against using nasty chemicals in the garden, let’s investigate the top natural insect repellents that will keep your beloved plants safe from harm.
Then let’s roll!
- What’s Eating My Garden Leaves?
- How to Stop Insects Eating Plant Leaves
- What Is a Natural Bug Killer?
- Is Baking Soda Good for Bugs On Plants?
What’s Eating My Garden Leaves?
Before you can decide on the best natural insect repellent to use, it is a good idea to figure out what is eating your garden leaves in the first place. Finding the garden culprit will help you choose the most effective method to stop insects from eating plant leaves.
Here are some of the common garden pests that are likely to damage or eat your outdoor plants and vegetables:
|Mostly on cucurbit stems and leaves. I’ve seen them attack zucchini, pumpkins, butternut squash, and cucumbers.
Squash bugs suck the sap from the leaves of plants belonging to the cucurbit family – mainly squashes and pumpkins, but sometimes also zucchini and cucumbers. These plants can withstand minor damage, but a severe squash bug infestation can cause the leaves to wilt and die.
Adult squash bugs are dark gray-brown with a flattish body and prominent antennae. They lay clusters of round yellow-bronze eggs on the undersides of leaves of squash plants, which hatch into nymphs after around ten days.
Did you know there are estimated to be around two million different species of beetle? Many of these, such as ladybugs, are very helpful in the garden. However, some can be problematic when it comes to leaf damage:
|Cucumber beetle damage is tricky to spot. But cucumber beetle infestations often result in tiny holes in the cucurbit plant leaves with yellow, wilting leaves.
Striped and spotted cucumber beetles are yellow and black – and attack all plants in the cucurbit family, but they most often dwell on cucumbers. They are notorious for spreading the pathogen that causes bacterial wilt, which can devastate the entire crop. Adult cucumber beetles also feed on the stems of plants, causing them to wilt and die.
|Flea beetles damage plants by eating tiny holes in leaves. The holes are only around 3 millimeters. Flea beetles don’t eat in one spot for long. So – you’ll likely notice several tiny holes in random locations.
Flea beetles are a tremendous pest in the garden, causing significant damage to leafy green vegetable crops such as spinach, arugula, cabbage, and broccoli. These frequent insects are teeny and hard to spot, but if you look closely, you will see them jumping when disturbed – just like a flea!
|Asparagus beetles feast on asparagus spears. When damage gets severe – you notice the asparagus shoots get brown and wane. Asparagus beetles will also eat leaves.
As the name suggests, asparagus beetles like to munch on asparagus spears, causing significant damage to this gourmet food crop. There are two types of asparagus beetle, both around ¼ inch long with oval bodies. The common asparagus beetle is blue-black with cream-colored spots, while the spotted asparagus beetle is orange-red with black speckles.
Bean Leaf Beetles
|Bean Leaf Beetles attack leaf undersides. I’ve also seen adult bean beetles eat bean pods – including the beans.
Bean leaf beetles will cause small holes on the underside of the leaves of snap beans, potentially killing off younger plants and seedlings. Bean beetles are around ¼ inch long and come in various colors, but you can identify them by the black triangle marking just behind the head.
Squash Lady Beetle
|Squash lady beetles infest cucumbers, pumpkins, squash, and gourds. They feast on the leaf undersides. Adults are more diverse in feeding – attacking all leaf sides and plant fruit.
The squash lady beetle is a type of ladybug, but this one is not our friend! They feed on the leaves and fruits of cucurbits, including melons, pumpkins, and cucumbers.
|Arge ochropus (Rose sawfly)
|Sawfly larvae are infamous plant pests. They appear like caterpillars and chew holes in leaves. Adult sawflies usually eat pollen and nectar.
Both sawflies and their caterpillar-like larvae can cause considerable damage to the leaves of plants. Adult female sawflies make cuts in tender leaves and stems in which they lay their eggs. When hatched, the larvae feed on the leaves, consuming large amounts of foliage before they pupate into adults.
|Grasshopper leaf damage usually starts at the edge of the leaf – and works inwards. They often eat large portions of the leaf. I’ve also seen them eat garden crops – like beans, soybeans, lettuce, and kale.
Grasshoppers prefer grass and weeds. But during the dryer summer season, they may broaden their scope to include your garden plants and vegetables. They create round holes in plant leaves, often with jagged edges. These leaf-eating insects must eat at least 50% of their body weight in plant material daily. Their voracious appetite leads them to cause significant damage – surprisingly quickly!
|There are many scale insect varieties of the Coccidae family.
|Look for immobile, shell-like bugs accompanied by wilted and browning leaves, sluggish growth, fading, and lackluster fruit.
Scale bugs are so tiny that you probably won’t have realized they are insects at first! These miniature garden creatures suck sap from the leaves and stems of plants and trees, covering themselves in a waxy secretion as a disguise. So, if you’ve got little brown or grey spots on the leaves of your plants, they could well be scale.
|There are various leaf miner varieties.
|Leaf miner larvae live inside leaves and feed on the plant’s interior. The damage appears like tiny spiraling, mined tunnels within the leaf.
There are many different species of leaf-mining insects, but all cause similar damage. They feed within rather than on the surface of leaves, resulting in classic lines or dots of scar tissue. They rarely do enough damage to kill plants. But they can cause unsightly lesions on food crops such as leaf beets.
|There are various caterpillar varieties. The image above depicts a Monarch Butterfly caterpillar or Danaus plexippus.
|Caterpillars hungrily devour nearly any green foliage they can find. But – don’t kill caterpillars! They might turn into beneficial butterflies later in life. 🙂
Caterpillars are the larval form of butterflies and moths, renowned for their voracious appetites that can lay waste to plants in mere days or even hours. Newly hatched caterpillars can be hard to spot, but they grow rapidly and soon start to cause blatant leaf damage.
|Aphids suck plant tissue. A few aphids usually won’t damage plants. But, large infestations can wilt plants and yellow foliage. Large infestations also cause a sticky, honeydew residue on plants.
Aphids are tiny sap-sucking insects found in most gardens, and if only a few exist, they are not very problematic. However, an aphid infestation can weaken or even kill tender plants, and they can also spread several different plant viruses. These tiny, soft-bodied creatures range in color from black, brown, gray, green, yellow, or red.
|Megachile leafcutters chew small round holes in flower blossoms and leaves. They DO NOT devour the leaves – but use them as nesting material. I say they’re a beneficial species.
Leafcutter bees are fascinating creatures – they cut out sections of leaves from which they construct nests, often by rolling the leaf into a tube. While the damage caused by leafcutter bees can be unsightly, it is unlikely to cause permanent harm to the plant. These ingenious bees are vital pollinators and should be encouraged into your garden.
How to Stop Insects Eating Plant Leaves
Let’s examine some natural pest control methods that will stop invasive insects from eating your plant leaves. But before we resort to using these preparations, it is a good idea to look at other methods of reducing insect populations in your garden:
- Many beetles and bugs overwinter in plant debris. So offer the area around your ornamental and vegetable beds a tidying in the fall.
- In the spring, create a weed-free zone. It will act as a barrier between wild and cultivated areas.
- Remember that beneficial predatory insects and birds will do 99% of the work for you if you let them! Create habitats and use companion plants to encourage ladybugs, native bees, wasps, spiders, and preying mantids to your garden.
- Few natural insect repellents are effective against hard-shelled beetles, so check your vegetable plants regularly and squash or drown any Japanese beetles that appear. (But be careful not to hurt the ladybugs!)
While all these techniques can help to create a balanced ecosystem and healthy plants, sometimes problems can occur. So, if you’ve got an infestation spiraling out of control, let’s examine the best ways to control it!
What Is a Natural Bug Killer?
Natural bug killers use organic or natural ingredients to kill or repel problematic insects. Many gardeners prefer an organic pest control option, as commercially produced insecticides can leave residues on food crops and destroy healthy soil.
We’re all for staying away from nasty chemicals. But, finding natural insect control methods is tricky. Finding organic pest control options is even more difficult because very little supporting evidence exists regarding whether these methods work. Mostly, we’re reliant on anecdotal reports from other gardeners. Unfortunately, this also means we cannot be sure if these ‘natural’ products could hurt beneficial insects.
To help you decide on the best natural insect control methods to use, we’ve taken an in-depth look at the most common options:
1. Insecticidal Soap
Insecticidal soaps help control soft-bodied insects such as aphids, sawfly larvae, and young scales. The insect must soak with the liquid, which disrupts the cell membranes, causing it to die. Larger, hard-shelled beetles are usually immune to this homemade pesticide spray, which means our precious ladybugs are also safe.
Although you will come across recipes for homemade insecticidal soap, it is vital to steer clear of dishwashing soaps and clothes-washing detergents, as these will damage your plants.
How Do I Make Insecticidal Soap?
Use our easy insecticidal soap recipe. Mix equal quantities of pure liquid Castile soap and vegetable oil in a jar. Then, shake until emulsified. Add one teaspoon of this mixture to a spray bottle with one cup of warm water, shake well, and spray any infected plants. Take care not to use the solution in hot weather or direct sunlight, as damage to the plant can occur.
If you go onto any popular gardening forum, you will see neem suggested as a solution to every problem under the sun! But what is neem, and is it the answer to everything?
Neem oil comes from the seeds of the neem tree, and it is a natural pesticide that is effective against aphids, scale, and moth larvae. It does not harm birds, mammals, or beneficial insects. But – neem is mildly toxic to fish and other aquatic creatures.
To be effective, the targeted insects must eat the leaves of plants sprayed with a neem oil solution. Add one tablespoon of pure neem oil and one tablespoon of pure Castile liquid soap to one gallon of water, shake well, and spray over all plant surfaces until saturated. Repeat every 7-14 days.
3. Bacillus Thuringiensis
Bacillus thuringiensis (Bt) is a naturally occurring bacterium used as a biopesticide. There are many different strains of Bt, each effective against a separate type of problematic pest. The bacteria release toxic spores to the larvae of target insects when eaten.
Over 130 strains of Bt are available commercially, and this is one of the few natural insecticides that can kill beetle larvae.
4. Diatomaceous Earth
Another product often claimed to have miraculous properties, food-grade diatomaceous earth is a form of silica made from the fossilized remains of minuscule aquatic creatures. It works as a dry powder. It scrapes the soft bodies of insects and larvae and causes them to dry out.
Take care when using diatomaceous earth as an organic insecticide, as it can be harmful if accidentally inhaled. It needs dry conditions to work well. It needs to be reapplied after rain or during periods of high humidity.
5. Horticultural Oil
Horticultural oil is a natural insecticide available from many garden stores. It usually contains a blend of mineral oil and an emulsifying agent and works by suffocating soft-shelled insects such as aphids and scales.
Horticultural oil can harm beneficial insects. So, it should only be applied as a targeted treatment if significant infestations or severe plant damage occur.
Is Baking Soda Good for Bugs On Plants?
Sadly, there is a lot of misinformation about natural insect repellents – some don’t work at all, and others are harmful to the whole ecosystem rather than just targeting the problematic critter in question.
When it comes to baking soda, this falls into the first category. Although commonly recommended as a natural bug killer, baking soda is only effective if the insect consumes the powder – unlikely to happen with most of the problem pests we are dealing with!
Thanks so much for reading our plant-eating insect guide! We tried to showcase some of the most common garden invaders who love snacking and feasting on your garden plants.
Usually – we try to avoid using pesticides and herbicides. We love organic gardening.
But sometimes – infestations get out of hand – and some action is required.
What about you?
- What’s the worst garden infestation you’ve ever seen?
- Do you have garden pests in your yard right now?
- Do you agree that Mother Nature can usually handle pest issues without our help?
- Have you ever used pesticides in your yard? Or do you prefer organic pest-deterrent methods?
- What garden pest eradication methods work best for you?
We would love to hear your thoughts. We’re all in this together!
Thanks again for reading our leaf-eating-bug guide.
Have a great day!