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What's eating your landscape?

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What’s Eating at You? 

Better Yet - What’s Eating at Your Landscape?

Do you ever go through spells where something is bugging you and you just can’t seem to shake it? 

Well, that is exactly how a lot of landscape plants are feeing right now!

Before we jump into the bugs, let’s talk about the most important gift you can give your plants…

ATTENTION!
Healthy landscapes are a result of an Integrated Pest Management program. The first step of an IPM approach is maintaining healthy plant material with proper watering, feeding, and pruning. Insect activity increases on plant material that is already stressed. The second step is simply monitoring your plants. Weekly observation is critically important. Does the overall plant color look healthy? How do the leaves look?

Complete control is much easier when insects are noticed early and populations are small.

Here are a few of the things that may be eating at your landscape this week:   

Bagworms

  • ½-2” long spindle shaped bag wrapped in the foliage of the host plant.  Young bagworms are very hard to spot.

  • Favorite host plants are juniper, arborvitae, spruce, pine and cedar.  But, they can attach themselves to deciduous shrubs and trees. 

  • Females lay eggs in bags left on plants over the winter.  One female bagworm will lay as many as 500 eggs. The eggs hatch in the late spring and tiny larva crawl out and start feeding.  As they feed, they use silk and plant materials to protect and camouflage themselves.  Bagworms can strip a plant of foliage.   They are active from May through September.

  • Heavy infestations, particularly on the same plant year after year, can cause plant death.

  • When there are only a few, control is best done by hand picking.  If you have a large population an insecticide treatment should be made as soon as they are noticed.  Try to remove any bags left on plant material in the fall.  Bags left on the plant will serve as cocoons for females to lay more eggs. When removing bags, destroy them.  Do not pick and toss on the ground as the worm will crawl back to a plant.

 
Young bagworms are small and can be hard to see. They wrap themselves in the plant needles making them hard to notice.

Young bagworms are small and can be hard to see. They wrap themselves in the plant needles making them hard to notice.

If you notice a juniper or cedar starting to loose color, inspect for bagworms.

If you notice a juniper or cedar starting to loose color, inspect for bagworms.

Left untreated, large, heavy infestations of bagworms will kill mature trees and shrubs.

Left untreated, large, heavy infestations of bagworms will kill mature trees and shrubs.

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Aphids

  • A small, soft-bodied insect that is nearly invisible to the naked eye.  The honeydew, sticky substance they excrete is the easiest way to know aphids are active.  Colonies develop on the underside of the leaf and often are not noticed until the sticky substance starts to show.

  • They feed on the leaves, stems and buds of a wide variety of plants throughout the growing season.  Usually they attack the succulent new growth.

  • Aphids generally do not cause serious harm to mature plants, although they can be harmful to young plants.  Heavy populations can cause wilt and yellowing of leaves as the sap is removed.  Blooming trees and shrubs will see a reduction in flowers.  Aphids can promote sooty mold, a fungal disease, and spread viruses. 

  • Early detection is the key.  Aphids mature in 7-10 days and can produce 40-60 offspring resulting in population explosions in the thousands within a few weeks. 

  • When populations are small, a high-pressure blast of water can be used to wash the insects off the leaves.   Wiping the leaves with a soapy solution is also effective with early detection.  In most cases, once you notice the honeydew, it is best to treat with an insecticide.  A dormant oil application in the winter is helpful in reducing populations the following season.  Lady bugs can be used as a beneficial insect control when populations are small.

 
Aphids feed on the underside of the leaf and become noticeable as the leaf becomes covered with the sticky substance they excrete.

Aphids feed on the underside of the leaf and become noticeable as the leaf becomes covered with the sticky substance they excrete.

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Spider Mites

  • Very small (1/60 of an inch) that live on the underside of leaves and survive by sucking on the cell content of the leaves.  First shows up as stippling of light dots on the leaves.  Leaves then turn from bronze, to yellow, and then fall off. 

  • They get their name from the small silk protective webs they create. 

  • Because spider mite damage can look like many other plant problems, the best way to determine if it is spider mites is to shake the plant leaves over a white sheet of paper.  Spider mites will look like tiny moving black dots on the paper. 

  • They are active from early summer through fall, but the hotter and dryer the weather, the more severe the spider mite problem will become. 

  • Spider mites reproduce rapidly when conditions are perfect.  Spider mites can hatch in as little as 3 days and become mature within 5 days.  One female can lay up to 20 eggs per day during their 2-4 week life span.

  • The best control results from making two applications 7-10 days apart.

  • Adequate plant moisture during the hottest time of the year helps prevent population explosions.

 
Early signs of spider mites.

Early signs of spider mites.

Silk protective webbing formed by the spider mite.

Silk protective webbing formed by the spider mite.

To know if you have spider mites shake leaves over a white sheet of paper.    Spider mites will look like tiny moving black dots.

To know if you have spider mites shake leaves over a white sheet of paper.

Spider mites will look like tiny moving black dots.

 

Webworm

  • Caterpillars that weave a loose web around tree branches while they are munching on the leaves. 

  • Favorite trees include hickory, mulberry, oak, pecan, popular, redbud, sweetgum, and willow.  But, you can find them on most ornamental shade trees when populations are heavy.

  • There are typically two generations each season, but there can be as many as four.  First generation shows up in July and the last generation is in September or October.

  • Early generations won’t cause long lasting damage.  They are just unsightly.  The last generation can cause damage when the branch tries to re-bud just before a killing frost.  When this occurs, you can expect the affected branch to die.

  • The best control is to cut out any affected branches in the early generations when the webbing is small.  Completely dispose of the branch as the worms will exit the webbing and return to a tree.  If the population has increased to the point that pruning is not possible, an insecticide application will be needed.  The spray must penetrate the webbing to gain control of the caterpillars.  Dormant oil applications are a good idea as worms overwinter in tree bark.

 
The webworm caterpillar weaves a loose web around tree branches to protect themselves while they are destroying your tree’s leaves.

The webworm caterpillar weaves a loose web around tree branches to protect themselves while they are destroying your tree’s leaves.

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Inspect your plant material often.  Our landscapes represent large investments in both time and money. They add curb appeal and provide enormous benefits to the environment.  It is important that we do all we can to keep them healthy and growing.

Let us know if we can help you have any questions or concerns about your plant materials.

Lorne Hall

Hall | Stewart Lawn + Landscape

(405)367-3873