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The Gardener’s Dirt April 2007

April 2007

 The Gardener’s

Dirt

Information you can dig into

North Carolina State University
College of Agriculture and Live Sciences
North Carolina Cooperative Extension Service
Johnston County Center
2736 NC 210 Highway * Smithfield, NC 27577
919 989-5380
 

Shawn Banks
Extension Agent
Agriculture—Consumer Horticulture


In this Issue
Feature Article
Spotlight Plant
Announcements
Pest Alert
Gardening To-Do

This newsletter offers timely information for your outdoor living spaces.  Addressing the most common questions ranging from container gardening, tree pruning, wildlife management, to fire ant control, insect identification and lawn establishment. 

 


Feature Story Banner

 Beneficial Insects

By Tony LaVerde
Johnston County Extension Master Gardener

As gardeners we are likely to notice the insects in our yards and gardens.  Many of us when we first spot that pesky bug rush to spray it with an insecticide.  Consider this the next time you spot an insect, entomologists estimate that more than 90 percent of all insects we find in our back yards are beneficial.  Beneficial insects help balance out the eco system by their consumption of other insects and organic matter. 

Beneficial insects, that help control other insects, fall into two general categories: parasites and predators.  Parasites are usually the immature stage of wasps and flies.  The adult wasp or fly lays an egg in or on the host insect. The developing parasite usually feeds inside the host until it is time to change into an adult.  By this time the host insect is usually dead.

Tomato Hornworm being parasitized by wasp larva Predators are usually larger than parasites. Predators actively seek and capture their prey.  A single predator will kill and eat much prey during its life.  Common predators include adult and immature forms of lady bugs, immature lacewings, ground beetles, hover flies, adult and immature assassin bugs, praying mantids, spiders, some bees and wasps, and frogs.  However, praying mantids and frogs do not discriminate between good and bad insects, but are worth attracting to your garden.

Not all beneficial insects eat other insects; some are pollinators such as domestic bees, some flies and moths.  Many beneficial insect species are decomposers: Meaning they recycle nutrients from organic matter and help clean up the environment.  There are a large number of insects that have little direct effect on humans, but are essential food for birds, fish and other animals.

Attracting and maintaining a population of beneficial insects is important to managing insect pests in your garden. The way we do this is by including plants that will attract these insects. These plants include nectar-producing flowers like angelica, bee balm, buckwheat, calendula, cilantro, clover, daisy, dill, evening primrose, fennel, gypsophila, lovage, parsley, Queen Anne's lace, rue, sunflower, sweet alyssum, sweet cicely, thyme, valerian, and yarrow.  Most of these plants are available at your local garden supply store, or through catalogs and Internet sites.  Beneficial insects may also be purchased through catalogs and Internet sites.

Should biological controls be ineffective in controlling plant damage caused by insects, and the use of insecticides is necessary, use insecticides that are more selective in their activity and less harmful to beneficial insects.  Insecticidal Soap, Horticultural Oil, and insecticides that use biological organisms such as B.t. are the least toxic insecticides to beneficial insects.

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Spotlight Plant banner
Dutchman's pipe growing up an arbor.

Dutchman's Pipe


Aristolochia durior

Dutchman’s Pipe is a very vigorous growing vine.  It will create a thick green screen in a short period of time making it ideal for covering a fence, wall or trellis.  It has large, heart-shaped leaves and very interesting flowers that are shaped like a small pipe.  You may have to look hard to find the flowers–they are only a few inches long and are a yellow-green color.

This vine plays an important role in the life of native Pipevine Swallowtail butterflies. The flowers provide nectar for the butterflies, and the leaves are an important food source for the caterpillars. The vigorous growth of this vine makes it easy to share the leaves with these beautiful insects.

This native plant grows best in moist, well-drained soil, in full to partial sun.   It can reach heights of 30 feet tall.  It is a good plant for having few pest or disease problems, and as a bonus it withstands urban pollution quite well.

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Hand holding clipboard          Announcements banner heading          Hand holding clipboard


Southern Ideal Home Show at the State Fairgrounds in Raleigh April 13-15.  Extension's Successful Gardener will have a learning center set up in Dorton Arena where people can stop by and ask gardening questions of an Extension Agent or a Master Gardener.  There is a charge to get into the show.

Fire Ant Clinic at the Agriculture Building in Smithfield.  2736 NC 210 Highway. April 21 10:00am  Dr. Charles Apperson will present information on the life cycle and biology of the Red Imported Fire Ant.  This will help in knowing when and how best to control these insects.  He will also cover some of the product that can be used to control Fire Ants.  The Master Gardeners will have stations set up in the parking lot to demonstrate the proper use of the different types of chemicals.

Johnston Community College Arboretum
       Plant Sale-A-Bration  April 21 9am – 2pm.
Activities require preregistration and may require a small registration fee.  Call to reserve your seat 919-209-2052 or 209-2517 or e-mail fryel@johnstoncc.edu or parkera@johnstoncc.edu .

Backyard Organic Gardening – A workshop held at the Center for Environmental Farming Systems CEFS located in Goldsboro.  This is a free workshop that will be held Monday, April 16, 6:00 – 8:00pm.  Register for this and other CEFS workshops at their website www.cefs.ncsu.edu .

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Pest Alert!  Pest Alert!  Pest Alert!

Tent caterpillars in their nest in the branches of a tree

The tent caterpillars are coming out.  Driving down the road you will notice webs at the point where the branch meets the trunk of the tree, these are the nests for tent caterpillars.  It is best to treat them now while they are small using a pesticide containing B.t. as the active ingredient as these are the least toxic chemicals and are targeted specifically to caterpillars (lepidoptera larva).  Two of the products that are available include Worm Whipper and DiPel.  There may be others available, but these are the ones I know can be found in the area.  If you know of others please let me know.

Bees and wasps (Hymenoptera) are starting to become active.  Most insects in the Hymenoptera family are benificial insects.  If their nests are out of the way they should be left to do their jobs of pollinating flowers and controlling the other insect population.  If you happen to spot a swarm of honeybees, contact the Cooperative Extenstion.  We have a list of beekeepers who would love to collect the swarm for use in pollination of crops around the county.  (919) 989-5380

Fireblight, a disease on apples and pears, usually starts when the plants are in flower and the temperatures are between 70 and 80 degrees.  The disease looks like the leaves on the tree are burned and still hanging on the tree.  Cut the limb off as soon as the disease has been seen.  The cut should be at least 12 inches below the infected area, do not allow the infected tissue to touch the other parts of the tree or it will infect the other part of the tree.  Sterilize the pruners with alcohol, lysol, or bleach before using them again to prevent spreading the disease.

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Gardening to-do Banner

Our last frost usually comes around mid-April, tax time.  Although there is a possibility for frost after that, previous records indicate that there is about a 2% chance of frost after April 15.

Stay out of the garden when the soil is wet!  Working or walking on wet clay soil compacts the soil, decreasing oxygen.  Neither gardeners nor their plants can survive without oxygen.  In addition, working around wet plants (including turfgrass) is a good way to spread fungal diseases.  How can you tell if the soil is too wet?  Take a handful of soil from 4-5" below the surface and squeeze it in your fist.  If it crumbles, the soil is workable.  If it holds its shape, it needs to dry out for a few more days.

LAWN CARElawn mower clip art

  • Grass clippings are a great source of nitrogen.  Practice grasscycling, a recycling practice where you leave the grass clippings on the lawn to return nutrients to the soil.  This could reduce the amount of nitrogen needed in fertilizer for the year by 25%.  Clippings may also be composted (they're a great nitrogen source), or sprinkled onto flowerbeds as long as they're not allowed to mat together.
  • Warm season lawn seed may be planted toward the end of the month.  Call us for a copy of 'Carolina Lawns' which tells you exactly when and how much seed to plant.

TREES, SHRUBS & ORNAMENTALS

  • Renew mulch around trees, shrubs, and in garden beds. Make sure mulch does not touch the bark of trees or shrubs and extends to the drip line of young trees.
  • If rambunctious perennials have reproduced too freely, remove and pot the excess plants. Pass them along to friends and family. New gardeners will be thrilled to receive free plants. http://hgic.clemson.edu/factsheets/HGIC1150.htm
  • Don't overfeed azaleas and camellias. These shallow-rooted plants are not heavy feeders, and can be damaged by over-fertilizing.  Submit a soil sample to be tested (it's free) to determine if fertilizer is needed.  Use a slow-release, balanced fertilizer immediately after blooming. Apply it around the drip line of the shrub, according to label directions.
  • Special fertilizers for 'acid-loving plants' are not necessary; our soils are sufficiently acid naturally.
  • Watch for black spot and powdery mildew on roses – common problems in our humid climate. Although these diseases make the foliage look bad, the plants generally do well anyway. https://www.ces.ncsu.edu/depts/pp/notes/Ornamental/odin002/odin002.htmLacebug close up
  • Watch for lace bugs, the most common pest on azaleas.  Look for whitish, stippled leaves with shiny dark flecks on the undersides of the leaves. If found, treat with horticultural oil (an insecticide).  Be sure the spray reaches all parts of the leaves and stems, including the undersides of leaves.  https://www.ces.ncsu.edu/depts/ent/notes/O&T/shrubs/ort039e/ort039e.htm
  • Annual flowers such as zinnas, moonflowers, cleome, gloriosa daisies and sunflowers can be seeded in mid April.
  • Let spring bulbs die down naturally. Remove flower heads after the petals fade, and allow the foliage to die down naturally. Do not fold, twist or braid foliage. Once the foliage falls over, it can be removed. Leafy companion plants can hide yellowing bulb foliage. Tender bulbs such as ranunculus and anemone can be dug and stored when their foliage begins to yellow.
  • At the end of the month, plant summer bulbs like caladiums, lilies, gladioli, dahlias, and elephant ears.
  • Prepare new flower beds by loosening and amending the soil. All plants perform better when their roots can spread in loose, organic soil. Till the soil and incorporate organic matter, lime and fertilizer – according to soil test results (free kits available at this office)
  • Plant perennials now so they can become established before hot weather sets in.

VEGETABLES & FRUITS

  • Check tender shoots of vegetables and emerging perennials for aphids. If found, shoot off with water.  Fireblight damage on apple tree
  • Watch out for and control fireblight  on apple, blackberries and pear trees (including ornamental varieties). Affected branches look like they've been burned with a blowtorch. Control this bacterial disease by pruning diseased limbs back to 1 foot beyond the diseased area. Be careful not to let infected foliage touch healthy foliage (yes, it's that contagious), and disinfect tools between cuts to avoid spreading the disease.  Discard rather than compost the infected limbs. https://www.ces.ncsu.edu/depts/pp/notes/oldnotes/fd3.htm
  • Plant turnips before April 15. Plant pole beans, carrots, and winter squash after April 15.Peas on the vine
  • Cucumbers, corn, pumpkins, snap beans, watermelon, and cantaloupe may be safely planted at the end of the month.
  • Thin cool weather crops that were seeded last month.
  • Pick off blossoms of strawberries planted this season. Let plants mature a year before they bear fruit.
  • Keep tomatoes well-watered to avoid blossom end rot.

HOUSEPLANTSAntherium pink flowering

  • Divide overgrown house plants.
  • Gradually introduce houseplants to the out-of-doors for their summer "vacation." Give them partial shade at first; experiment to see which of them can handle sun. Even sun-lovers will need a few days in the shade, to get used to the intensity of sunlight, before going out onto a sunny patio.

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