Extension Master GardenerSM Volunteers of Buncombe County

IPM

Acronym for Integrated Pest Management: A strategy for keeping plant damage within bounds by carefully monitoring crops, predicting trouble before it happens and then selecting the appropriate controls — biological, cultural, or chemical as necessary.

Vegetable Garden Pests: Beware the Pickleworm!

Just inside from harvesting vegetables, I heard yelling from the kitchen. She was staring at a freshly washed cucumber in the sink. Sprouting from it were green projections that were alive and wriggling! This was our introduction to the insect pest with the unique name of pickleworm.

These critters are the larvae of the pickleworm moth (Diaphania nitidalis), which overwinters in Florida and becomes a late summer pest of cucurbits (not only cucumbers, but summer and winter squash, pumpkins, cantaloupe, and watermelons) in Western North Carolina.

Adult Pickleworm Moth

Life cycle

Once the moths arrive in our area, they lay eggs on cucurbits, which hatch, go through several larval stages, pupate in the plants’ leaves or in the leaf litter, and become adults in less than a month! This short life cycle means we may see two or even three generations of pickleworms a year.

Damage

The larvae can feed on flowers, leaves, and vines, as well as fruits. Larvae eating blooms can prevent fruit set. Like squash borers (Melittia cucurbitae), in the worst-case scenario, pickleworm larvae feeding on the vines can kill your plants. You may see pickleworm excrement (frass), or simply small holes in your fruits. In both cases, your crop is ruined once the larvae are feeding because the damaged areas with start to rot. According to University of Florida’s John L. Capinera, cantaloupes, with their thick skins, may have external damage called “rindworm.”

Pickleworm Larvae and Damage to Squash

Management

  • Early planting. Plantings that mature before the moths arrive are likely to escape pickleworm damage.
  • Resistant varieties. Some squash varieties that are more resistant: summer squashes Early Prolific Straightneck, Early Yellow Summer Crookneck, and Summer Crookneck; and Butternut 23 winter squash.
  • Floating row covers. Using row covers at night can prevent the night-flying moths from egg-laying, while still allowing pollinators to visit the flowers by day.
  • Garden clean-up. Removing damaged fruits and vines can prevent further generations in the same gardening season.

Learn more:

Pickleworm, University of Tennessee Publication # W206:

https://extension.tennessee.edu/publications/Documents/W206.pdf

University of Florida Featured Creatures:

https://entnemdept.ifas.ufl.edu/creatures/veg/pickleworm.htm

Insect Management on Cucurbit Vegetables in North Carolina

https://entomology.ces.ncsu.edu/cucurbit-insect-management-in-north-carolina/

Non-Native Invasive Plants: Tree of Heaven

Once you learn about non-native invasive plants they seem to be everywhere! One of the worst of these—Ailanthus altissima—has the misleading common name “Tree of Heaven.” Introduced as an ornamental, Ailanthus is an attractive, fast-growing tree—but when cut back it can sprout up more than 10 feet a year! Water and wind can spread seeds that will grow new trees as tall as 6 feet their first year.

Ailanthus trees produce a lot of pollen and all parts of the tree can produce skin irritation in some individuals. If that doesn’t give you pause, we now have a new reason to double down on eliminating this invader: it is the preferred host tree for an exceedingly destructive insect, the spotted lanternfly (Lycorma delicatula), which may be making its way south! Removing Ailanthus now will make North Carolina less hospitable to this planthopper, which is a major pest of many fruits, including apples and grapes.

Adult Male Lanternfly

How to know if you have tree of heaven?

Characteristics to look for:

  • Bark: Smooth bark that looks somewhat like cantaloupe skin.

  • Ailanthus Bark
    Ailanthus Bark
  • Leaves: Each leaf has from 10 to 40 leaflets with smooth edges, except for 1 to 2 “teeth” at the bottom of each leaflet. Leaves have a very strong peanut-butter odor.

  • Aialnthus Leaves
  • Flowers: Yellowish flowers April through June.

  • Ailanthus in Bloom
  • Seeds: Winged seed pods in large clusters that may stay on the trees in winter.

  • Ailanthus seed Pods

Management

Tree of heaven is difficult to control because of its extensive root system and re-sprouting ability. Success depends on treatment timing and following up the next year. Be sure to wear gloves and other protective clothing when removing tree of heaven because of the possibility of allergic reactions.

Mechanical

  • Hand-pull young seedlings as soon as they are large enough to grasp. They are best pulled after a rain loosens the soil.
  • Remove the entire root because small root fragments are capable of generating new shoots.
  • Note that root suckers are easily confused with seedlings and are nearly impossible to pull by hand.
  • Although cutting down a tree of heaven will cause it to re-sprout and sucker, you may want to prune out limbs during the winter after leaf fall.
  • If seed clusters are present on cut limbs, collect, bag, and dispose of in heavy trash bags so they will not sprout have a chance to sprout.

Chemical

  • Herbicides containing the active ingredient triclopyr are effective. Apply all chemical treatments between July 1 and when the tree begins to show fall colors.
  • When removing a tree of heaven, use foliar herbicide sprays where tree height and distribution allow effective coverage without unacceptable contact with nearby desirable plants.
  • Treat the foliage with an herbicide first, allow 30 days for it to take effect before cutting the tree down.

 Native alternatives for Ailanthus altissima

Suggested by NCSU’s “Going Native” website:

  • Hickories (Carya)
  • Fringetree (Chionanthus virginicus)
  • Green Ash (Fraxinus pennsylvanica)
  • Smooth Sumac (Rhus glabra)

                              Article by Debbie Green, Extension Master GardenerSM Volunteer

 For more information:

Identifying:

https://projects.ncsu.edu/goingnative/howto/mapping/invexse/treeofhe.html

https://extension.psu.edu/identifying-tree-of-heaven-and-some-native-look-a-likes

More on landscaping with native alternatives:

https://projects.ncsu.edu/goingnative/index.html

Spotted lanternfly watch:

https://ipm.ces.ncsu.edu/wp-content/uploads/2018/10/SpottedLanternflyPestWatch.pdf?fwd=no

 

Beneficial Insects: Attract the Good, the Voracious, and the Ugly to Your Garden

Early on, I learned that nature has many solutions to insect problems. My father, an entomologist, and grandfather, a horticulturalist, used chemicals only when all else failed—a philosophy that flew in the face of America’s love affair with pesticides in the 1960s. Today we call this approach to gardening Integrated Pest Management (IPM). 

Integrated Pest Management
According to Craig Mauney, Extension Specialist, IPM involves looking for long term solutions, not short-term fixes. “This requires us to be highly engaged gardeners,” Mauney says. “By that I mean we prevent problems by properly planting the right plants. We look for evidence of insect damage as plants grow and observe patterns of plant decline. When there are problems, we use mechanical, cultural, and biological tools first. Chemicals are a last resort.” 

Biological Management
North Carolina State University’s (NCSU) Extension Gardener Handbook defines biological management as “the process of reducing a pest population by using predators, parasitoids (often called parasites), or disease organisms that ordinarily occur in nature.” Why? Because in the great web of life, plant-feeding insects are food for other insects.

Matching Predator and Pest
Sounds good, but how does the home gardener know which beneficial insects to encourage? Good places to start are the Buncombe County Extension Master GardenerSM Volunteers Helpline (828-255-5522) and NCSU’s Cooperative Extension website. Common beneficial predators in western North Carolina gardens include: ground beetles, ladybird beetles, lacewings, wheel bugs, hoverflies, and predatory mites. These active insects have long life-cycles and prey on smaller, weaker insects, usually devouring them in one gulp. 

Ladybug_Hippodamia-tredecimpunctata_Gilles-San-Martin_CC-BY-SA-2.0_Flickr
Ladybird or ladybug beetle devours aphids

Ladybird or Ladybug Beetle
According to the University of Florida’s Entomology Department, the name of these familiar red and black insects “has been used in England for more than 600 years…The lady for whom they were named was the Virgin Mary, and common names in other European languages have the same association (the German name Marienkafer translates to Marybeetle or ladybeetle).” How can the ladybird better help your garden? Some of the pests they help control include aphids, scales, whiteflies, and mites. 

Lacewing_Nell Kelley_CC BY-NC 2.0_Flickr
Green lacewing

Lacewings
Lacewings are distinguished by roof-like, transparent wings that are held over the insect’s body. Known as “aphid lions,” the larvae of the lacewing emerge hungry and voraciously feed on aphids and other soft-bodied insects, such as mealybugs, scales, thrips, whiteflies, spider mites, leafhopper nymphs, and caterpillar eggs. According to Michigan State University, “natural control of aphids is possible when there is one (lacewing) larva per 70 aphids.” Not bad for an insect that grows to just a half-inch long! These beneficial insects are particularly sensitive to pesticides, however!

Wheel Bugs or Assassin Bugs
We know them as those sinister-looking, long-snouted, brown insects that appear in great numbers each spring, often in places where we don’t want them, like our homes and cars. One place we do want them is in the garden. These predators prefer dining on soft-bodied insects such as caterpillars, moths, aphids, and small beetles. Wheel bugs are not aggressive, but they can give you a painful bite if handled improperly. If you have to pick one up, use a paper towel to gently remove it to the great outdoors where it can protect your garden.

Syrphid fly_Debbie Ross_NCState_AgExtAgent
Syrphid fly or hover fly

Hoverflies or Syrphid flies
They look like wasps but they’re really flies. The name—hover fly—comes from the way they hang in the air during flight. In their adult form, they are pollinators. In their larval form, they are predators. The larvae are often found among aphid colonies, one of their favorite foods. These doubly beneficial insects are sensitive to several broad-spectrum pesticides, especially organophosphates (OP) such as parathion and malathion.

Promoting Beneficial Insects
Want to attract beneficial insects? An important key is to plant so that there are blooms year-round in the garden. Opt for native plants that flower and include both flowering annuals and perennials to feed beneficial insects.

Article written by Janet Moore, Extension Master GardenerSM Volunteer.

Contact Us

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

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