Insects
Common garden pests & insects

While working in residential and commercial landscapes we often encountered the same insect pests, repeatedly damaging the same plants.

This page includes photos of these insect pests along with brief comments and descriptions of the damage caused by these insects.

Scouting for insects is done by studying twigs, checking the undersides of leaves, and closely examining growing tips. A commonly used tool when scouting for insects is a 10-power hand lens magnifier.


  APHIDS (aka "plant lice")  Aphids are very common plant pests and often work in a symbiotic relationship with ants, so ant activity often means aphid activity.  They especially like Spirea -- in this photo the 'Snow Mound' variety. Aphids are often the cause of sticky spots (from honeydew) on vehicles parked beneath aphid-infested trees. Aphids tend to congregate near the growing tips of branches.

APHIDS (aka "plant lice")
Aphids are very common plant pests and often work in a symbiotic relationship with ants, so ant activity often means aphid activity.  They especially like Spirea -- in this photo the 'Snow Mound' variety. Aphids are often the cause of sticky spots (from honeydew) on vehicles parked beneath aphid-infested trees. Aphids tend to congregate near the growing tips of branches.


  BAGWORMS  By late summer, this Arborvitae was showing widespread bagworm damage. Controls: Bt (Bacillus thuringiensis) or an approved insecticide in June, or hand pick the bags in late Fall to destroy overwintering eggs.     These caterpillars create silk bags camouflaged with foliage from the host plant.

BAGWORMS
By late summer, this Arborvitae was showing widespread bagworm damage. Controls: Bt (Bacillus thuringiensis) or an approved insecticide in June, or hand pick the bags in late Fall to destroy overwintering eggs.
These caterpillars create silk bags camouflaged with foliage from the host plant.

   Notice the "bags" on this arborvitae.     Bagworms lose their camouflage and become much more noticeable as these bags turn brown. Unchecked infestations will lead to rapid plant demise.

Notice the "bags" on this arborvitae. Bagworms lose their camouflage and become much more noticeable as these bags turn brown. Unchecked infestations will lead to rapid plant demise.


  BLACK VINE WEEVIL    Black Vine Weevil adults cause the "C-shaped" leaf notching on Rhododendron leaves and other plants, but their more severe damage is caused by the root weevil stage that damages plant roots. A root drench of insecticide to control the grub stage is usually applied in late June in the northeastern US. Always read and follow pesticide label instructions.

BLACK VINE WEEVIL
Black Vine Weevil adults cause the "C-shaped" leaf notching on Rhododendron leaves and other plants, but their more severe damage is caused by the root weevil stage that damages plant roots. A root drench of insecticide to control the grub stage is usually applied in late June in the northeastern US. Always read and follow pesticide label instructions.


  CARPENTER ANTS    Photo of "mined out" heartwood on a tree trunk. This wild cherry tree broke-off at the base during a wind storm, hitting a house. Carpenter ants love wet wood in trees and houses. Purchase carpenter ant bait here

CARPENTER ANTS
Photo of "mined out" heartwood on a tree trunk. This wild cherry tree broke-off at the base during a wind storm, hitting a house. Carpenter ants love wet wood in trees and houses. Purchase carpenter ant bait here

   Carpenter ant damage to the heartwood of the tree.

Carpenter ant damage to the heartwood of the tree.


  DOGWOOD BORER    Dogwood borer is the most significant pest of Flowering Dogwood (Cornus florida). Dogwoods planted in full sun are much more likely to be attacked by dogwood borer than those planted in partial shade, due to the tree's increased stress level. Avoid damaging trunks with weed whackers and lawnmowers. Adults emerge in late May. Notice the "drilled holes" in the photo.

DOGWOOD BORER
Dogwood borer is the most significant pest of Flowering Dogwood (Cornus florida). Dogwoods planted in full sun are much more likely to be attacked by dogwood borer than those planted in partial shade, due to the tree's increased stress level. Avoid damaging trunks with weed whackers and lawnmowers. Adults emerge in late May. Notice the "drilled holes" in the photo.


  EASTERN TENT CATERPILLAR  Eastern Tent Caterpillars show-up quickly in the spring and are easily identified by their webs being located in the "crotch" of a branch. In stark contrast, Fall Webworm tents are formed at branch tips.

EASTERN TENT CATERPILLAR
Eastern Tent Caterpillars show-up quickly in the spring and are easily identified by their webs being located in the "crotch" of a branch. In stark contrast, Fall Webworm tents are formed at branch tips.



  GRUBS    "C-shaped" Japanese Beetle grubs can cause extensive lawn damage by chewing off grass roots. The many different types of soil grubs are identified by the pattern of hairs on their rear ends which are known as "rasters."

GRUBS
"C-shaped" Japanese Beetle grubs can cause extensive lawn damage by chewing off grass roots. The many different types of soil grubs are identified by the pattern of hairs on their rear ends which are known as "rasters."

   Sod was very loose on this home lawn and had several brown areas. Grubs eat grass roots causing sod to brown-out and feel loose when you pull up on it.

Sod was very loose on this home lawn and had several brown areas. Grubs eat grass roots causing sod to brown-out and feel loose when you pull up on it.

  GYPSY MOTH    Easily identified by its double row of red and blue dots, this caterpillar is one of the most destructive forest pests in the US, defoliating trees (Oak & Aspen are favorites). Biological controls Bt and "Gypchek" are used for control.    

GYPSY MOTH
Easily identified by its double row of red and blue dots, this caterpillar is one of the most destructive forest pests in the US, defoliating trees (Oak & Aspen are favorites). Biological controls Bt and "Gypchek" are used for control.
 


  JAPANESE BEETLES  The adults usually appear around the 4th of July and "skeletonize" the leaves of plants. Purple plums (photo) are one of their favorites. The larval stage is known for the damage it causes to lawns by eating the roots off grass, causing large brown areas of turf, mostly in the fall and spring (see 'Grub' photos above). Chemical lawn treatments are timed for late-summer to early-fall when the grub is youngest and most vulnerable. Biological control: Milky Spore is effective again st Japanese Beetle grubs.

JAPANESE BEETLES
The adults usually appear around the 4th of July and "skeletonize" the leaves of plants. Purple plums (photo) are one of their favorites. The larval stage is known for the damage it causes to lawns by eating the roots off grass, causing large brown areas of turf, mostly in the fall and spring (see 'Grub' photos above). Chemical lawn treatments are timed for late-summer to early-fall when the grub is youngest and most vulnerable. Biological control: Milky Spore is effective against Japanese Beetle grubs.


  LACE BUG  Speckled leaves on PJM Rhododendron (photo above), Azaleas and Pieris are usually a sign of Lace Bug damage.

LACE BUG
Speckled leaves on PJM Rhododendron (photo above), Azaleas and Pieris are usually a sign of Lace Bug damage.

   Check the undersides of leaves to detect active Lace Bug adults during summer months. The adults are 1/8-inch long with clear, lace-patterned wings. The undersides of leaves will have brown splotches.

Check the undersides of leaves to detect active Lace Bug adults during summer months. The adults are 1/8-inch long with clear, lace-patterned wings. The undersides of leaves will have brown splotches.


  PINE NEEDLE SCALE  This insect will make needles on a pine look like they have snow on them. Commonly seen on Mugo Pines but also infests Scotch Pines. Control the crawler stage in late May with horticultural oil or insecticidal soap sprays. Dormant oil applications in fall or spring are less effective.

PINE NEEDLE SCALE
This insect will make needles on a pine look like they have snow on them. Commonly seen on Mugo Pines but also infests Scotch Pines. Control the crawler stage in late May with horticultural oil or insecticidal soap sprays. Dormant oil applications in fall or spring are less effective.


  SAWFLY  Check your pines VERY carefully in May for these extremely well camouflaged pests! First indicator of their presence are needles that have been chewed to stubble, find that location and the caterpillars will be close by. Sawfly damage occurs very quickly and those needles won't grow back! They can be sprayed or handpicked.

SAWFLY
Check your pines VERY carefully in May for these extremely well camouflaged pests! First indicator of their presence are needles that have been chewed to stubble, find that location and the caterpillars will be close by. Sawfly damage occurs very quickly and those needles won't grow back! They can be sprayed or handpicked.


  SCALE ON JUNIPERS    Typical insect controls for Scale - Dormant season: Horticultural oil applied in early spring before new growth appears. Growing season: Contact insecticides that kill young scale crawlers.    

SCALE ON JUNIPERS
Typical insect controls for Scale -
Dormant season:
Horticultural oil applied in early spring before new growth appears.
Growing season:
Contact insecticides that kill young scale crawlers.

 

  SCALE ON LILACS    Typical insect controls for Scale - Dormant season: Horticultural oil applied in early spring before leaves appear. Growing season: Contact insecticides that kill young scale crawlers.

SCALE ON LILACS
Typical insect controls for Scale -
Dormant season:
Horticultural oil applied in early spring before leaves appear.
Growing season:
Contact insecticides that kill young scale crawlers.

  SCALE ON MAGNOLIA    Typical insect controls for Scale - Dormant season: Horticultural oil applied in early spring before leaves appear. Growing season: Contact insecticides that kill young scale crawlers.

SCALE ON MAGNOLIA
Typical insect controls for Scale -
Dormant season:
Horticultural oil applied in early spring before leaves appear.
Growing season:
Contact insecticides that kill young scale crawlers.

  SCALE CRAWLERS  Notice the small "crawler stage" of Magnolia Scale in the BOBscaping photo above.

SCALE CRAWLERS
Notice the small "crawler stage" of Magnolia Scale in the BOBscaping photo above.

  SIGNS OF SCALE INFESTATIONS    Scale insects excrete a sticky substance called "honeydew" on which black sooty mold will eventually grow. If you see a plant leaf "painted black" (like the Magnolia leaves above) check further to see what insect pest has infested your plant. Also, ants and bees are often seen around honeydew.

SIGNS OF SCALE INFESTATIONS
Scale insects excrete a sticky substance called "honeydew" on which black sooty mold will eventually grow. If you see a plant leaf "painted black" (like the Magnolia leaves above) check further to see what insect pest has infested your plant. Also, ants and bees are often seen around honeydew.

VIDEO: Maple Scale
What to look for when scouting for insects on trees, like these shiny sticky spots on Maple leaves. Further examination revealed SCALE infestation, notice them lined-up along the branches. Improve the vigor of your trees with annual fertilization in Spring.