Extension Master GardenerSM Volunteers of Buncombe County

Plant Insects

Gardening Video: Managing Bad Bugs in Your Vegetable Garden

Saturday Seminar presents:
Managing Bad Bugs in Your Vegetable Garden—Lessons from The Learning Garden

Squash Vine Borer adult_Lisa Brown_CC BY-NC 2.0_Flickr
Squash vine borer adult

Presenter: Laura Brooks, Extension Master GardenerSM Volunteer

Now that you’ve planted your vegetable garden, it’s time to discuss the nemesis of every veggie gardener: bad bugs!  Which ones should you look out for and what can you do about them?

Laura Brooks, co-chair of The Learning Garden’s vegetable plot located at the Buncombe County Extension office, highlights the three most common pests that were encountered last year in The Learning Garden: squash vine borers, flea beetles, and Mexican bean beetles. She describes the organic methods that Master Gardeners used to help ward off these pesky insects.  Laura explains the life cycle of these insects, what they look like from larvae to adult stages, when they emerge, and effective treatments.

To access this video on the Buncombe County Master Gardener website, click on the link:

Managing Bad Bugs in Your Vegetable Garden

Or go to www.buncombemastergardener.org, click on the ‘Resources’ tab at the top of the page and select ‘Gardening Videos’ from the drop down menu.

Pest Alert: Nantucket Pine Tip Moth

If you’re spending more time outside as the weather warms, you might notice problems in your landscape. One homeowner called the Garden Helpline about white webbing on the ends of some of the branches of a tree purchased as a live Christmas tree. She planted the tree in a special place in her yard as a reminder of that happy occasion. Although she knew it was a pine, diagnosing the problem required determining what pine species it was. The number of needles in each needle bundle can identify pine species. She reported that there were 3 needles in each bundle, helping identify the tree as a Scotch pine (Pinus sylvestris), a very popular Christmas tree species.

Scotch PIne three needle bundle
Three needle bundle pine

Damage: The description of the webbing she saw helped determine that her tree was infested with the Nantucket pine tip moth, (Rhyacionia frustrana). Other signs include:

• Deformed growth (stem crooking) or a reduction in growth (bushy or stunted growth);
• Fecal deposits may be present in the webbing on the outside of infested shoots;
• Trees can be killed when exposed to repeated Nantucket pine tip moth larval infestations.

Damage caused by Nantucket Pine Tip Moth

Identification:

• In North Carolina, this pest overwinters as pupae in hollowed out pine shoots;
• On warm days as early as January and February, new moths emerge to mate;
• Adult moths are 1/4 inches (6.3 mm) long with the head and body covered with gray scales. The forewings are covered with brick-red to copper-colored patches that are separated by irregular bands of gray and white scales;
• Adult females lay white to opaque eggs on shoots, needles, or terminal growth in spring;

Adult Nantucket Pine Tip Moth

• From 5 to 30 days later, young larvae (caterpillars) hatch from eggs and feed on the surface of new growth. These are 1/16 inches (1.6 mm) long, and cream-colored with a black head. They then move to the shoot tips, construct protective webs at the base of buds, and begin to bore into the bud or stem.
• Feeding continues inside the bud or stem until the caterpillars are fully grown in 3 to 4 weeks. The caterpillars then pupate inside the damaged stem.

Management:

• Proper watering, fertilization, and mulching practices to keep pine trees healthy;
• For minor infestations, you can hand prune infested shoots if branches are reachable.

Susceptible pine species:

• Other three needle bundle pines, which include pitch pine (P. rigida) and loblolly pine (P. taeda).
• Two needle bundle pines are highly susceptible to infestation. These include Japanese red pine (P. densifolia), mountain pine (P. mugo) and Japanese black ine (P. thunbergii).

Resistant pine species:

  • Eastern white pine (P. strobus) and Virginia pine (P. virginiana), which have five needle bundles.

                                        Article by Bob Wardwell, Extension Master Gardener Volunteer

For more Information:
Nantucket Pine Tip Moth: https://content.ces.ncsu.edu/nantucket-pine-tip-mo

How to Identify Pines: https://smallfarms.cornell.edu/2019/02/arent-they-all-just-pines-how-to-id-conifer-trees/

Pest Facts: Hemlock Woolly Adelgid (HWA)

Just visit a Western North Carolina forest to see how much destruction this non-native invasive insect pest has caused—and is still causing—on the native Carolina hemlocks (Tsuga caroliniana) and Eastern hemlocks (Tsuga canadensis)! After our recent rains, this is a good time to treat your hemlocks if you see a white cottony substance on your hemlocks.

Hemlock Woolly Adelgid

History

  • HWAs were discovered in Shenandoah National Park in northern Virginia in 1988, likely when crawlers clung to the legs and feathers of migrating birds, such as the black-throated green warbler and solitary vireo that visit or nest in hemlock trees.
  • HWAs were discovered on hemlocks in North and South Carolina in late 2001 and early 2002.

HWA (Adelges tsugae) Life Cycle:

  • HWAs hatch from eggs and then go through a crawler stage—almost invisible to the naked eye. These crawlers cannot fly on their own but can drift in the air from tree to tree, and cling to the legs and feathers of migrating birds.
  • After settling on host trees, the HWAs insert a bundle of mouthparts at the base of a needle and spend the rest of their lives—a few months—sucking nutrients out of the tree.
  • The name “woolly” comes from the fact that adult HWAs are covered with a protective white fluff once they settle.
  • The HWA goes through two generations a year (one in March and one in October in Western North Carolina) and each female—even without being fertilized by a male—can lay between 100 to 300 eggs.
  • This reproductive process is called “parthenogenesis”—the offspring are genetically identical clones of their mother.

Controls

Chemical: Registered pesticides containing imidacloprid or dinotefuran are the most effective chemical treatments for control of HWAs. These are applied as a soil injection or trunk spray. These insecticides are water soluble and move into the tree’s vascular system along with water. Dinotefuran has a faster uptake, but imidacloprid has a longer residual protection. Control of HWAs using imidacloprid can last for 4-5 years. Dinotefuran may require retreatment within 2 years.

Biological:

The species that has so far shown the most promise as a biological control agent is Laricobius nigrinus, a predator beetle native to the Pacific Northwest. L. nigrinus is active from October to March; both adults and larvae will consume all stages of HWAs: eggs, nymphs and adults.

After exhaustive evaluation in quarantine labs, it was cleared by the USDA for use as an HWA biocontrol in the eastern United States in 2000 and has been released in NC since 2003.

Original Article by Glenn Palmer, Extension Master GardenerSM Volunteer, Revised by Bob Wardwell, Extension Master GardenerSM Volunteer

Hemlock Restoration Initiative https://savehemlocksnc.org/

National Park Service Great Smoky Mountains Hemlock Woolly Adelgid

https://www.nps.gov/grsm/learn/nature/hemlock-woolly-adelgid.htm

University of Massachusetts HWA Fact Sheet https://ag.umass.edu/landscape/fact-sheets/hemlock-woolly-adelgid

Contact Us

Buncombe County Extension Office
49 Mount Carmel Road
Asheville, NC 28806
Helpline 828-255-5522

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