GARDEN INSECTS & PESTS

• Aphids
• Bagworms
• Black Vine Weevil
• Carpenter Ants
• Dogwood Borer New!
• Eastern Tent Caterpillar
• Grubs
• Hemlock Woolly Adelgid
• Holly Leafminer
• Japanese_Beetles
• Lace Bugs
• Pine Needle Scale
• Rodents... voles?
• Sawfly
• Scale
• Whiteflies

Landscape Pest Scouting Reports
Penn State Cooperative Extension
Call 1-800-736-6476
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Pest Activity

Aphids (plant lice)

Aphids are very common plant pests and often work in a symbiotic relationship with ants.  They especially like Spirea -- in this case the 'Snow Mound' variety.

Bagworms

These caterpillars create silk bags camouflaged with foliage from the host plant. Bagworms become much more noticeable as bags turn brown.
   

By late summer, this Arborvitae was showing widespread bagworm damage. Controls: apply Bt or an approved insecticide in June, or hand pick the bags in late Fall to destroy overwintering eggs.

Black Vine Weevil

Black Vine Weevil adults do the noticeable "C-shaped" leaf notching on Rhododendron leaves, but the real damage is caused by the root weevil stage which damages the roots. A root drench of insecticide to control the grub stage is usually applied in late June in the Pittsburgh, PA area.

Carpenter Ants

We wouldn't ordinarily include Carpenter Ants with other plant insect pests. However, after seeing a "tunneled out" wild cherry tree break off at the base during a windstorm, it only seemed appropriate. Carpenter ants weakened the heartwood of the tree enough that it blew down, hitting a house. Carpenter ants are drawn to wet wood.

Dogwood Borer

Notice the "drill holes" in this trunk

Dogwood borer is the most significant pest of Flowering Dogwood (Cornus florida). Dogwoods planted in full sun are much more likely to be impacted by dogwood borer than those planted in partial shade, due to their increased stress level. Avoid damaging trunks with weedeaters and lawnmowers. Adults emerge in late May.

Eastern Tent Caterpillar

Eastern Tent Caterpillars arrive quickly in the spring and are easily distinguished by their location in the "crotch" of a branch.  In stark contrast, Fall Webworm tents are formed at the branch tips.

Grubs

While aerating this home lawn in September we noticed the sod was loose and had several brown areas. Further examination revealed 'C-shaped' Japanese Beetle grubs. Grubs eat grass roots causing sod to brown and feel loose when you pull up on it. The many different types of soil grubs are identified by the pattern of hairs on their rear ends which are known as 'rasters.'

Japanese Beetles

The adults suddenly appear around the 4th of July and "skeletonize" the leaves on plants. Purple-leafed plums are one of their favorites. The larval stage is best 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 into early-fall when the grub is most vulnerable. Biological control: Milky Spore is effective against Japanese Beetle grubs.

Speckled leaves on PJM Rhododendrons (photo above), Azaleas and Andromeda (Pieris) are usually a sure sign of lace bugs. Look at the undersides of leaves to detect active adults during the summer months. The adults are 1/8-inch long with clear, lace-patterned wings. The undersides of leaves will also have brown splotches.

Pine Needle Scale

This insect will make the needles on your pine look like they have snow on them. It's most commonly seen on Mugho Pines in landscapes, 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.

"Rodents"... voles?

These blue rug junipers (photo above) appeared at first glance to have 'tip blight' fungus.
   

Upon closer examination, small chewing rodents (Voles?) had stripped bark off the branches (photo above) girdling them enough to cause browning foliage on branch tips.  We've seen several cases like this in 2001

Sawfly

Check your Pines carefully in May for these camouflaged invaders.  Look first for the areas where needles have been chewed to stubble... the caterpillars will be close by.  They can be sprayed or handpicked.

Scale  (Magnolia)

A black substance on plant leaves usually indicates the presence of a sucking insect excreting excess honeydew. Black sooty mold grows on the honeydew giving the leaves a blackened appearance. This 'sweet' honeydew on the leaves may attract bees as well as ants. Scale insects (white, top left, in photo above) have infested this Magnolia tree.

Close examination of the tree branches reveals a large infestation of 'bumper to bumper' scale, resembling small oyster shells....these are the Mama scales.  Young scale crawlers emerge from beneath these 'turtle shells.' Dormant oil sprays, properly used, will provide good control of this insect pest, and be less harmful to the environment than most other pesticides. Read and follow label directions, they are there to help.

Scale crawlers can be seen emerging in July
on this Magnolia in Pennsylvania
  

Scale (Lilac)