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.

Non-Native Invasive Plants: Oriental Bittersweet (Celastrus orbiculatus)

If you knew how awful it is, you would have nothing to do with oriental bittersweet! It is an aggressive, woody, deciduous, perennial vine capable of girdling stems and trunks of shrubs and trees, damaging their bark and underlying tissue. Despite its weedy behavior, oriental bittersweet is still sold and planted as an ornamental vine and should be avoided.

Oriental bittersweet vine chokes tree_photo by G. Merrill
Oriental bittersweet vine

Identification:

  • Leaves: Finely toothed, round glossy leaves are arranged alternately on the vine. They range from 2 to 5 inches long and 1.5 to 2 inches wide.

    Oriental bittersweet (Celastrus orbiculatus)_Leonara Ellie Enking_CC BY-SA 2.0_Flickr
    Oriental bittersweet foliage
  • Flowers: Clusters of 2 to 7 blossoms where the leaf attaches to the stem (leaf axil). Each flower has 5 petals and 5 sepals.
  • Fruit: Green-to-yellow round fruits ripen in the fall. Upon ripening, the fruits split open revealing three red-orange, fleshy berries that remain on the vine through the winter. The many birds and small mammals that feed on the berries distribute seed far and wide. A single plant can produce almost 400 fruits!

    Oriental Bittersweet_berries_Katja Schulz_CC BY 2.0_Flickr
    Oriental bittersweet Fruit
  • Distribution: Oriental bittersweet’s distribution ranges from central Maine south to North Carolina and west to Illinois;
  • Ecology: It can grow in woodlands, fields, hedgerows, coastal areas, and salt marsh edges. It tolerates shade but prefers full sun.

Management Options:

  • Mechanical control: Pull light infestations by hand—before fruiting, if possible. If fruits are present, bag the vines to make sure the seeds do not contaminate the site. Cutting the vines at the base early in the season will prevent flowering and fruiting, but you must remove all of the roots so the bittersweet will not re-sprout. Frequent mowing will also exclude oriental bittersweet, but infrequent mowing—two to three times a year—can stimulate root suckering.
  • Chemical control: You can successfully manage heavy infestations of non-native bittersweet with herbicides containing the active ingredient Triclopyr. The chemical is most effective applied immediately to the cut stem surface of cut or mowed vines. Apply herbicides prior to the emergence of native plants or after the last killing frost to help avoid herbicide contact with desirable plants. As with any herbicide, carefully follow the label guidelines when handling and applying.

American bittersweet (Celastrus scandens) is native to the eastern United States and is easily confused with oriental bittersweet. Leaf shape is highly variable and not a good characteristic for identifying American vs. Oriental bittersweet. Watch for flowers and fruits to distinguish the two:

  • American bittersweet flowers and fruits are only found at the ends of stems, Oriental bittersweet flowers and fruits are found all along the stem at leaf axils.
  • American bittersweet has orange capsules around red fruits, Oriental bittersweet has yellow capsules around red fruits.

A HOLIDAY CAUTION: Do NOT use oriental bittersweet in outdoor decorations! If you have any decorations containing oriental bittersweet fruits, be sure to bag them and discard—Do not compost!

Article by Bob Wardwell, Extension Master GardenerSM Volunteer

For More Information:

 

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

 

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

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