Although mulberry trees are resilient, they can still be vulnerable to insect infestations. It is important to understand the various pests that can affect mulberry trees.
To ensure you’re well prepared for a possible bug infestation, we’ve listed 20 of the most common mulberry tree insect pests, how to identify them, and how to send them packing!
Pests can certainly be a nuisance and lead to a weakened tree, but there are other issues that you should be aware of as well. Learn all about them in my comprehensive guide, Mulberry Tree Diseases, Pests & Problems.
1. Mealybugs
These small oval-shaped bugs are roughly 4 millimeters long and have soft grayish-white to pink bodies that resemble mold or cotton wool in large gatherings.
Together, they feed off the plant sap and excrete honeydew, weakening growth and generally creating a mess.
Solution
A strong spray of water can normally knock mealybugs off on sight! To prevent them altogether, spray foliage with neem oil as this suffocates soft-bodied pests.
2. Leaf Rollers
Leaf rollers are inch-long caterpillars with bodies ranging from deep green to dark brown with black spot markings along their backs and dark heads.
These critters feed on tender new leaf growth, damaging terminal buds and causing overall slow production. They can also feed on the fruit in high numbers.
Solution
Pick off caterpillars by hand, or knock them into a bucket of soapy water, and prune the infected shoots.
Apply the biological fungicide Monterey B.t. to poison current populations. Introduce beneficial predators like lacewings or the parasitic Trichogramma wasp.
3. Bihar Hairy Caterpillar
These are 4.5-5 centimeters in length with light-brown bodies and brick-red abdomens with dark spots dotted on their back.
Bihar caterpillars have a fierce appetite during development, defoliating entire leaves to the point that only the veins are exposed! Early signs are dried-up or yellowing leaves.
Solution
Flooding the soil can expose and kill overwintering bihar larvae as can a deep summer tilling, which also improves soil quality. Treat caterpillars on site with a broad-spectrum insecticide like Lambda-cyhalothrin.
4. Wingless Grasshoppers
Adults are 13-18 millimeters long with short, undeveloped wings and brown-greenish bodies that can sometimes feature white stripes along the back.
Wingless grasshoppers feed heavily on mulberry foliage during the growing season, leaving entire branches without leaves.
Solution
You can expose grasshopper eggs in the soil with deep tilling in late summer to let natural predators do their thing.
Monitor for early signs of leaf damage so you can spot-treat with insecticide. Look for tiny black grasshoppers (smaller than a matchhead) on the ground and in the vicinity of your tree.
5. Leafhoppers
Adult leafhoppers are usually light green and between 2.5 and 4 millimeters long. They have large leaf-like wings and move sideways, living on leaf undersides where they suck the sap.
In large numbers, badly damaged leaves will drop prematurely.
Solution
Leafhoppers are attracted to light, so set up some light traps to deter them from your tree. To kill infestations on contact, a spray of broad-spectrum insecticide or pyrethrin (plant-based) insecticide will do the trick.
6. Thrips
These straw-colored slender bugs are no larger than a sewing needle and have small feathery wings.
Thrips will lacerate leaf tissue and cause serious drying and distorted foliage due to their sap-sucking habit that can result in widespread leaf loss.
Solution
Identify warped or skeletonized leaves, and prune them immediately to prevent further thrip spread.
Spray neem oil onto minimally damaged foliage to disrupt their reproductive cycles. Also, keep a weed-free zone below your tree as weeds can host the next thrip generation.
7. Cutworm
Cutworms are wide, dull-colored green or brown caterpillars measuring 4-5 centimeters that develop into adult cutworm moths with grayish to dark brown patterned wings.
True to their name, these pests eat and “cut” young mulberry shoots, resulting in dried-up growth that soon falls off.
Solution
Poison baits can be set up to lure and kill cutworm larvae (2 spoons of moist wheat bran or oats mixed with insecticide).
You can also go out with a flashlight and pick off the nocturnal larvae by hand or lure beneficial predators like wasps, ground beetles, or nematodes to the soil.
8. Whitefly
Whiteflies are found on lower leaf surfaces and have white, waxy triangular bodies measuring only a 1/16 of an inch.
Like mealybugs, these pests suck leaf sap and secrete honeydew, and in mass infestations, they can cause leaves to yellow and drop.
Solution
Mulberry whitefly eggs and the dainty adults can be dislodged with a blast of water, and you can treat large colonies with a neem oil spray, killing whiteflies at any life stage.
To prevent these nuisances, Janet Loughrey at Garden Design recommends covering the ground in a reflective metallic fabric mulch to confuse them enough to avoid the area altogether!
9. Scale Insects
Scale bugs are 1/8 inch long with oval white or brown shell-like coatings. They can resemble small bumps on tree leaves, stems, and bark where they feed on the tree sap.
Left to their own devices, large groups will cause leaves to yellow and wilt and the stressed bark to crack and ooze gum.
Solution
Prune growth with large-scale invasions, and spot-treat individual bugs with cotton swabs soaked in rubbing alcohol.
Reducing your fertilizer use can help limit visits from them as this reduces nitrogen levels, making the sap less appealing!
10. Stem Borers
These winged insects are 4-5 centimeters long with elongated brown to dark gray bodies and long (sometimes striped) antennae.
As you can guess, stem borers feed on shoots and stem tissue and bore tunnels inside branches. A sure sign of their presence is frass (poop) near the tunnel hole entrance.
Solution
Prune and destroy infested shoots and branches if damage is significant. Otherwise, hang sticky traps to trap adult moths, and inject a natural liquid insecticide into frass holes to kill any stem borer larvae or eggs.
11. Beetles
A common beetle pest is the stem girdler beetle, which is roughly 3/8 of an inch long with light gray or tan-brown bodies and long antennae.
These attack and girdle stems and branches, leaving a clear ring around the infected shoot — the portion above the ring slowly wilts and dies.
Solution
Remove any fallen twigs and stems as these will contain beetle larvae or eggs and destroy them immediately.
Prune off damaged growth well below the girdle ring and destroy it. Spot treat adult girder beetles with a neem oil foliar spray.
12. Termites
Termites are whitish or colorless insects with short antennae that measure up to an inch long.
They love to feed on the hardwood of the stems and bark, leading to significant foliage loss and potential tree death when dealing with large termite colonies.
Solution
One of the best ways to destroy termite colonies permanently is to remove the queen termite.
Enlist the help of a licensed termite inspector who can recommend the most appropriate control methods, such as termiticides or bait systems, based on damage.
Be careful with your choice of mulching material, as dry twigs can create an attractive environment for them!
13. Webworms
These appear like common green or yellow caterpillars with slender 1¼-inch long bodies and black heads, but their damage belies their size.
Together, they spin large tents or webs that can sometimes cover 2-3 feet across branches.
Solution
This webbing damage is mostly cosmetic, but the larger the webbing, the more worms there are munching on leaves, which will contribute to tree stress.
Use a long broom to sweep out and bag up web tents. You can also attack and kill overwintering webworm eggs with a foliar spray of dormant oil in early spring.
14. Aphids
Aphids can be pale green to orange-red pear-shaped insects ranging from 1-7 millimeters. They gather on stems and leaf undersides to suck out the sap.
Damage is most notable with large infestations as leaves begin to curl or develop large holes, with trees growing deformed in severe cases.
Solution
Small numbers can be picked off and crushed in a paper towel. Larger numbers can be dislodged with a high-power hose spray.
Follow this up with a spray of organic homemade insecticidal soap or pesticide (3 parts dish soap, 1 part water). Depending on the visible damage, you may need to prune entire leaves or branches.
15. Glassy-Winged Sharpshooter
This distinctive species of leafhopper is ½ inch long with dark-brown bodies and smoky-gray wings with red stained-glass-like markings.
Glassy-winged sharpshooters not only feed on leaf sap, but they are also known to transmit the bacterium Xyella fastidious that can contribute to diseases like mulberry leaf scorch.
Solution
Applications of insecticidal soap may deter them, but to prevent the pests in the long term, consider introducing beneficial predatory insects like dragonflies or parasitic wasps – the latter lay their eggs inside glassy-winged sharpshooter
eggs and eat their way out!
16. Spider Mites
A common spider mite species seen on mulberry trees is the two-spotted spider mite.
These have oval near-translucent bodies about 0.4 millimeters long with an orange-red color and dark spots on either side. Their feeding with needle-like mouthparts creates tiny white flecking on leaves and a fine silky webbing.
Solution
A simple soapy water solution spray will dislodge and suffocate spider mites, and a spray of neem oil or rosemary oil onto the affected foliage will kill and help deter future numbers.
17. Fruit Flies
As larvae, fruit flies are white or transparent while the adults are 3-6 millimeters long with brownish with rounded heads and large red eyes.
These flies create pin-prick-sized holes in the fruit to lay eggs, and larvae eat their way out, affecting fruit yield and quality.
Solution
Harvest mulberries as soon as possible as fruit flies are mostly drawn to overripe and decaying fruit.
Remove and bag up affected fruit, and clear any fallen fruit beneath the tree to prevent disease and overwintering larvae.
18. Nematodes
These are microscopic roundworms that mostly inhabit dry sandy soils in hot climates.
Their damage only becomes apparent at a late stage — small leaf and fruit production, overall stunted growth, and galls, knots or splitting at the roots.
Solution
Deep tilling of the soil in summer can help expose active nematodes to the sun and predators.
Amending the soil with neem cake is also advised — this is a natural nematicide made from the cold pressing of neem fruit and seed kernels.
19. Weevils
This beetle species is often less than 6 millimeters long with elongated snouts and lightbulb-shaped beige or dark bodies.
Weevils feed on leaf sap, creating irregular serrated edges while the larvae can feed on stems and even the roots.
Solution
Clear tree debris to minimize larvae populations and consider drenching the soil with systemic insecticide.
Sylvia Dekker from Gardener’s Path also recommends setting up pitfall traps by sinking cups half-filled with soapy water into the soil, so the cup lip is level with the soil surface. Genius!
20. Lacebugs
Lacebugs are gray insects 2-10 millimeters long with flat bodies and ornate lacy wings. Their feeding on foliage sap leaves behind white-yellow spots and dark varnish-like spots on the undersides.
Solution
These pests overwinter as eggs in leaf litter, so try to keep a debris-free and weed-free base at your mulberry tree.
Prune badly affected foliage, and spray mildly damaged leaves with an application of pyrethrin or Monterey horticultural oil.
To Conclude
Mulberry tree pests come in all shapes, sizes, and destruction levels! The good news is that most of the above critters won’t do enough damage to kill your mulberry tree altogether, but early detection is key to eradicating them.
As well as closely monitoring the leaves, soil, and bark for signs of trouble, it always helps to have some natural insecticide at the ready, and perhaps consider some companion plants for your tree to keep certain pests at bay.
Being well-informed is critical for proper tree care. Read these articles next to learn more about common mulberry tree issues:
- 16 Common Mulberry Tree Problems and How To Correct Them
- 17 Mulberry Tree Diseases & How To Manage Them Effectively