Green caterpillars are one of the most recognizable (and often unwanted) visitors to your garden, and are often found munching on the leaves of various ornamental and edible plants, shrubs, and trees.
For the most part, caterpillars are harmless to humans but some may cause skin irritations when touched, or even spit acid in defense! So, it’s a good idea to identify any green caterpillar first before attempting to hand-pick it.
If you want to know what you’re dealing with, this A to Z guide will take you through the 32 most common green caterpillars in your yard and how to identify them by their size, markings, spines or spikes, the plants they usually feed on, and the types of butterflies or pretty garden moths they turn into.
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As an avid gardener, you’ve likely encountered small green caterpillars munching away on the leaves of your plants. While most caterpillars are harmless, some can cause extensive damage especially in large numbers. When you spot green caterpillars crawling on your plants how do you know if they are a threat? This guide will help you identify the most common small green caterpillars with black heads, providing tips on managing them in your garden and yard.
What Do Small Green Caterpillars with Black Heads Eat?
The diet of small green caterpillars depends on the specific species. However, they mostly enjoy feeding on the leaves of trees, shrubs, garden vegetables, and agricultural crops. Some of the plants at risk include:
- Fruit trees – apple, pear, cherry, plum
- Ornamental shrubs – azalea, rhododendron
- Garden vegetables – cabbage, broccoli, kale
- Field crops – soybean, alfalfa
While these caterpillars are small in size, just a few can quickly decimate the leaves on a plant in a short period Keep an eye out for signs of damage, like chewed foliage, to identify an infestation early
Identifying Features of Small Green and Black Caterpillars
While many types of inchworms and loopers are light green, the species covered in this guide have some common traits:
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Size Average length when mature is 1/2 to 1 inch Some may reach 1 1/2 inches
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Color: The body is some shade of green – bright green, yellow-green, or olive green. The head capsule is dark black or brown.
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Movement: When disturbed these caterpillars thrash around rapidly or let themselves drop suspended from a silk thread.
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Host Plants: They feed on a variety of trees, shrubs, vegetables, and field crops. Preferred hosts depend on the exact species.
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Habits: Some species roll or tie leaves together to form shelters. Others feed openly.
7 Common Small Green Caterpillars with Black Heads
Here are some of the most prevalent small green and black caterpillars you may find damaging plants:
1. Obliquebanded Leafroller
The obliquebanded leafroller (Choristoneura rosaceana) is a bright green caterpillar with a black head frequently found in soybean fields, but also feeds on corn, alfalfa, apples, pears, and roses. The larvae reach 1/2 to 3/4 inch long at maturity. As the name suggests, the adult moths have angled, brownish bands across their tan wings.
2. Azalea Sawfly
The azalea sawfly (Masoncus pyriformis) is common in the southeastern U.S. The yellow-green larvae with black heads feed on azaleas, rhododendrons, blueberries, and other ericaceous plants. They reach 3/4 to 1 inch in length.
3. Pear and Cherry Slugs
Pear slugs and cherry slugs are actually the larvae of sawflies in the genera Caliroa and Eriocampoides. The slimy green caterpillars have black heads and eat the leaves of pear, cherry, and other fruit trees. They are typically under 1/2 inch long.
4. Elm Sawfly
The European elm sawfly (Cimbex americana), introduced to North America, is a 1 inch long green caterpillar with a brownish-black head. As the name suggests, it feeds on elm leaves but has also been found on willow, poplar, and birch trees.
5. Fall Webworm
The fall webworm (Hyphantria cunea) is a type of a small yellowish-green hairy caterpillar with long spikes. It feeds on the leaves of walnut, cherry, crabapple, and other deciduous trees. The fuzzy caterpillars grow up to 1 inch long.
6. Diamondback Moth Caterpillar
The diamondback moth caterpillar (Plutella xylostella) is a small, pale green caterpillar with black spiny hairs on its body, small white dots, a brown to black head, and a tapering rear. It emerges almost colorless from the egg and gradually develops a green body and black head as it grows.
7. Fruittree Leafroller
The fruittree leafroller (Archips argyrospila) overwinters as groups of eggs on branches. The young green larvae have black heads. They reach about an inch long and feed on apple, pear, and other fruit tree leaves and buds.
How to Control Small Green Caterpillars
If you spot a light infestation of small green caterpillars on a few branches, you can pick them off by hand and drop them in a bucket of soapy water. For heavier infestations, here are a few management options:
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Organic sprays – Bacillus thuringiensis (Bt) is a natural bacteria that kills caterpillars when ingested but is safe for humans. Use it on small larvae.
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Pesticides – Insecticidal soaps, neem oil, pyrethrins, carbaryl, and spinosad are options for quick caterpillar control. Avoid overuse to protect pollinators and natural predators.
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Natural predators – Birds, parasitic wasps, praying mantises will help control populations. Avoid broad-spectrum insecticides.
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Physical barriers – Wrapping susceptible plants in netting or aluminum foil can exclude egg-laying moths.
Promptly treating small, localized infestations of small green caterpillars can often prevent them from defoliating trees and crops. Always identify the species first so you know their likely host plants and best control methods. With vigilance and a combination of control tactics, their damage can be minimized.
Description of the Pest
Fruittree leafroller overwinters in the egg stage in irregular masses of 30 to 100 eggs cemented over with a secretion. Young larvae are light green caterpillars with black heads and are first seen at bud break. The mature larva is about an inch long and has a green body and black head. The black head helps distinguish fruittree leafroller from other leafrollers. There is one generation per season.
The fruittree leafroller feeds principally on leaves, but also feeds on blossoms, flower buds, and fruits during bloom. Tiny larvae work their way into opening leaf buds to feed. Once the tree has leafed out, larvae tie up leaves and live within leafrolls, feeding on leaves or fruit. Larvae damage fruit in much the same way as green fruitworms, resulting in shallow cavities in the fruit. Damaged fruits that remain on the tree develop deep bronze-colored scars with roughened, netlike surfaces.
Generally fruittree leafrollers are the first caterpillars seen in samples taken after green tip and have about 2 weeks to feed before the first codling moth spray goes on. Young larvae are easiest to control because they have not yet constructed a nest out of leaves, which protects them from insecticides.
Natural enemies specific for fruittree leafroller are not known, but a number of general predators, such as lacewing and lady beetle larvae, and parasites feed on fruittree leafroller larvae. Although these natural enemies help keep fruittree leafroller populations at low, nondamaging levels; occasional outbreaks still occur, especially in the San Joaquin and inner coastal valleys.
Applications of approved narrow range oil, Bacillus thuringiensis, and the Entrust formulation of spinosad are organically acceptable.
How to identify green caterpillars
Caterpillars are the larvae of various species of moths or butterflies. When identifying a green caterpillar, it’s important to remember that caterpillars go through multiple molts and life stages (known as instars) and may not always look like the pictures below.
Young caterpillars may be lighter in color or have different markings and other physical characteristics (such as stripes, spikes, or horns) than mature caterpillars, which often turn brown right before they pupate. So besides appearance, consider the type of plant it’s crawling or feeding on to help you determine what kind of caterpillar is in your garden.
Related: How to identify the most common striped caterpillars in your yard
For ease of ID, the pictures and descriptions below are of mature caterpillars before they enter pupation.
Recommended products for caterpillar control:
New Species of Caterpillar with Bright Green Glow in the dark head. Found in Laguna Beach, CA
FAQ
What is a small green caterpillar with a black head?
Fruittree leafroller overwinters in the egg stage in irregular masses of 30 to 100 eggs cemented over with a secretion. Young larvae are light green caterpillars with black heads and are first seen at bud break. The mature larva is about an inch long and has a green body and black head.
What butterfly comes from a green and black caterpillar?
Black Swallowtail Butterfly Larvae
Caterpillars are pale to yellowish green with irregular black cross bands that partially surround yellowish to orange spots. They feed on parsley, parsnip, celery, carrot, dill, caraway, Queen Anne’s lace, and many other related plants.
What kind of caterpillar is green with black spikes?
Hickory horned devil caterpillar
It has a brown head, a dark green body covered in black spines, and black prolegs.
What are the little green caterpillars hanging from trees?
Have you noticed little white or green caterpillars hanging by silk threads from the trees? What are they? Most likely they are the larvae (caterpillars) of either oak leafrollers or oak leaftiers, two different species of moth. Leafrollers are from the genus Archips and leaftiers are from the genus Croesia.
What is a black and white caterpillar?
It is a small green caterpillar with black and white dots on its body. The crawling insect loves feeding on the foliage of honeysuckle, sweet peas, wild indigo, and acacia. The black oval head with white dots is the distinctive feature for easy identification.
What does a green striped caterpillar look like?
Green striped caterpillar with cylindrical body and black head. Black dots on the abdomen produce fine setae. It is a large moth caterpillar with a green body, rear yellow fleshy horn, and two large blue and white eyespots. It can grow up to 8.5cm long.
What does a tropical caterpillar look like?
Bright green body with dark longitudinal stripes and two black horns. It is a long dark green caterpillar with a large head, scary-looking horns, whitish-yellow lateral stripes, and tiny white dots. These tropical caterpillars are harmless and feed on leguminous plants.
What is the smallest green caterpillar?
The diamondback caterpillar is one of the smallest green caterpillars you’ll come across as it’s only about 1 centimeter (0.4 inch) long. It has a pale green body, five pairs of prolegs (with the back pair forming a V shape at the rear), and a black or brown head. What are the green caterpillars in my garden?
What does a black caterpillar look like?
The caterpillars are yellow-green with a black line that runs down the dorsal side. Their heads are black and maroon with yellow and red-orange side stripes. The black head has a yellow or orange spot, that can be seen on both sides. These caterpillars feed on vine legumes, including beggars ticks, wisteria, hog peanuts, and blue peas.
What does a green horned caterpillar look like?
Large plump green body with a long spiky tail and a triangular head. It is a green-horned caterpillar that hails from Florida, Texas, South Carolina, and Mississippi. The lime green body and diagonal white stripes are distinctive features. The large spiky horn on its tail is an additional feature and does not sting.