Invasive Insect Damages US Ash Trees

A beetle invasion in the United States has killed at least twenty million ash trees. The invasion of the emerald ash borer was first discovered near Detroit, Michigan, in 2002. Experts believe the small green insects arrived in the 1990s in shipments of goods from China.

The emerald ash borer has destroyed trees in the Midwest and as far east in the United States as Maryland. The insects have also spread as far north as Ontario, Canada. Emerald ash borers are attacking tree farms and can also spread when logs and firewood are transported.

Ash trees are popular. They grow well in heavy clay soils, and they can survive ice storms well. They produce many leaves, so they provide shade protection from the sun. And in the fall the leaves turn a beautiful gold and purple.

Ash trees can resist many diseases. But they cannot resist the emerald ash borer. It lays eggs on the bark. Then the young larvae drill into and feed on the inner bark. This harms the ability of the tree to transport water and nutrients.

The United States Department of Agriculture is working to save the ash tree. So are agriculture departments and university extensions in a number of states.

In some places, farmers are using "detection trees." These have an area where bark has been cut away. The area circles the tree and is called a girdle. The girdling process weakens the trees. It makes them easier targets for borers, and shows if the insects are nearby.

Efforts to stop the spread of the emerald ash borer include cutting down affected trees. A tree farmer in Maryland, for example, recently faced the loss of hundreds of trees.

There are worries that the ash tree might disappear unless the invasion is controlled. To prepare for such a possibility, a government laboratory is collecting seeds from ash trees.

David Burgdorf works in East Lansing, Michigan, for the Natural Resources Conservation Service; the service is part of the United States Department of Agriculture. He is asking people to send in ash seeds. The laboratory examines and x-rays the seeds to make sure there are no living borer embryos.

The best seeds are then sent for storage in a seed bank in Fort Collins, Colorado. There, they are dried and frozen at the National Center for Genetic Resources Preservation. Should the seeds ever be needed, the hope is that scientists might someday develop an ash tree that could resist the little green attackers.

Source:
VOA News Service

Plants Invite Insect Allies to Dine on Pests

Students are taught at an early age about how insects help plants reproduce. Schoolchildren learn that plants release sweet juices, or nectar, through small openings inside the flower. These small openings are called nectaries.

The sweet-smelling nectar appeals to bees and other insects so they go to the plant. While the bee is drinking the sweet nectar, the hairs on its legs become covered with pollen. The bee flies to another flower and drops some of the pollen there.

During a flight, the bee usually visits several male and several female flowers. In this way, flowers are able to reproduce.

Many plants, however, release nectar for another purpose. Scientists have known about it for more than one hundred years.

The second way plants release nectar does not involve flowers. The nectar is contained in extrafloral nectaries. They are found on the tops of leaves, where the leaf and stem come together.

Trees that have extrafloral nectaries include the peach, poplar, viburnum, black locust and wild cherry.

Extrafloral nectaries are often smaller than a grain of salt. Researchers say the sweet juices released in them are not used to help the plant reproduce. Instead, they are used to get some insects to come to the plant to help control harmful insects.

Scientists have known for many years that tiny ants feed on the sweet juices released by the extrafloral nectaries. But only in more recent years did they make discoveries involving other insects.

Back in 1984 there was a report about extrafloral nectaries in Agricultural Research magazine. The magazine is published by the United States Agriculture Department. It reported that two government scientists, Robert Pemberton and Jang-hoon Lee, had studied extrafloral nectaries for two years. They looked for ways to control gypsy moths.

They did their research in forests near the South Korean capital, Seoul. During their research, they discovered that two helpful insects liked the extrafloral nectaries.

In fact, the insects killed two times more gypsy moths on trees that had the extrafloral nectaries than on those that did not. The insects are the Cotesia melanoscelus wasp and the Parasetigena silvestris fly.

A third insect, the Blepharipa schineri fly, also improved its control of gypsy moths on trees with extrafloral nectaries.

Source:
VOA News Service
Author: Bob Bowen
First published: November 7, 2005

Insects Devouring Your Garden? Call in the Ladybugs

There are plenty of insects that farmers hate. But there also are some they like. These protect crops against damage from other insects. A good example is the lady beetle, also known as the ladybug.

Lady beetles are a natural control for aphids. Aphids are tiny insects that develop colonies on plants and eat plant fluids. Aphids can also spread crop diseases. Adult lady beetles can eat fifty aphids a day. The young beetle larvae can eat hundreds of aphids.

Lady beetles are red, orange or black. They often have black spots, though some have light colored spots. Different kinds of lady beetles have different numbers of spots. There are lady beetles with four, five, seven and fourteen spots.

Many of the well-known kinds of lady beetles come from Asia or Europe. They now are common throughout the United States.

American scientists imported one kind of lady beetle, the multicolored Asian lady beetle, as early as nineteen sixteen. They released them as an attempt to control some kinds of inspects. Over the years, the beetle has become established, possibly helped by some that arrived with imported plants on ships.

Experts say over four hundred fifty kinds of lady beetles are found in North America. Some are native to the area. Others have been brought from other places. Almost all are helpful to farmers.

The Asian lady beetles now in the United States probably came from Japan. The Asian lady beetle eats aphids that damage crops like soybeans, fruits and berries.

In the southern United States, Asian lady beetles have reduced the need for farmers to use pest-killing poisons on pecan trees. This popular tree nut suffers from aphids and other pests that the beetles eat.

But some people say the Asian lady beetle has itself become a pest. Lady beetles have no food after crops have been harvested. It is time for them to prepare for winter. Normally this is in the ground, but it can also be in someone’s home. Some farmers also worry that the beetles may eat their late-autumn fruit crops.

Experts say Asian lady beetles may appear in large numbers in some years. But they say the insects are too helpful to consider pests.

Source:
VOA News Service
Author: Mario Ritter
First published: April 10, 2006

Bee Shortage Threatens California's Crops

A tiny pest is threatening California's community of honey bees and therefore its crops, which could affect the harvest of some of America's favorite fruits.

Bees are especially important to California's almond orchards because they go from flower to flower, pollinating the blossoms that will grow into almonds.

Jim Huddleson, an almond grower, says without bees, "Very little crop, just a little bit from the wind maybe a very small crop if any."

The problem--thousands of bee colonies are under attack from a parasitic mite.

"Actually, it is about the size of a head of a pin that actually attaches itself to the body of a bee and essentially sucks life out of it," said Orin Johnson, a California beekeeper.

Beekeepers like Orin Johnson rent hives and put them in the almond orchards. When the bees are finished pollinating the almond blossoms, the hives will be moved to cherry groves, apple orchards and melon patches. The bee shortage means farmers are paying much more per hive, if they can find any. Beekeepers have to bring in hives from Florida, on the other side of the country, and even as far away as Australia.

But Orin Johnson is doing everything he can to keep his bees healthy, including sticking his bare hand into the hive to check on the bees' health.

"That is why some people say beekeepers are nuts. Grown men playing with insects," says Mr. Johnson.

But for many farmers, the bee shortage is no laughing matter as they struggle to save their crops.

Related topic: Attracting Bees, Butterflies and Moths to Your Backyard

Source:
VOA News Service
Author: Kimberly Russell
First published: February 25, 2005

Attracting Bees, Butterflies and Moths to Your Backyard or Garden

In the United States, there are nearly 5,000 different species of native bees. Most of them are solitary, friendly bees that nest in holes in the ground or burrows in twigs and dead tree limbs. These bees do not have hives to protect them, so they are not aggressive and rarely sting. Bumblebees, carpenter bees, sweat bees, leafcutter bees, digger bees, and others pollinate many different kinds of plants. They play a critical role in healthy wild plant communities and gardens. About 30 percent of our diet is the direct result of a pollinating visit by a bee to a flowering fruit tree or vegetable plant. Providing bee habitat in your yard can increase the quality and quantity of your fruits and vegetables.

Bees are extremely sensitive to many commonly applied insecticides. If you must use chemical insecticides in your garden, apply them in the evening when bees are less likely to be active.

Bees are attracted to most flowering plants, and are especially fond of blue and yellow flowers. Try planting your garden to have different species blooming in the spring, summer, and fall.

Bee houses

A good use for untreated scrap lumber (at least 3 to 5 inches thick) is to drill holes (from 1/8-inch to 5/16-inch in diameter) about 90 percent of the way into the thick wooden block. Space the holes about 1/2-inch to 3/4-inch apart. The 5/16-inch holes work best as homes for orchard bees which are excellent pollinators of fruit trees. Hang your bee blocks under the eaves of your house or garden shed, protected from direct sun and rain.

Attracting butterflies and moths

Colorful butterflies and moths add beauty and interest to your backyard. There are hundreds of different species of butterflies and moths in North America. Butterflies and moths are insects. They hatch into larvae (commonly referred to as caterpillars), eventually become pupae, and develop into colorful adults. How long the process takes depends on the species and the climate.

Butterflies and moths are amazingly particular in their food choices. The larval stage of the butterfly may require food quite different from that of the adult. Some larvae consume tremendous amounts of plant material, seemingly devouring plants overnight. A common example in the garden is the tomato hornworm which rapidly strips tomato plants of their leaves. An equally voracious, but beautiful, larvae is the Eastern black swallowtail which is found only on plants in the carrot family, including celery, carrot, dill, and parsley. A close relative is the Eastern tiger swallowtail that eats the foliage of wild cherry, birch, poplar, ash, and tulip trees.

Adult butterflies require food in liquid form such as plant-produced nectar. They get some of it from flowers and from juices of extra-ripe fruit. The types of flowering plants you grow will determine the kinds of butterflies you attract to your backyard. In addition to the plants listed for hummingbirds, butterfly bush is especially attractive. Find out what species are common in your area and use plants they like. Nectar feeders can be placed in the yard to attract butterflies. Do not use insecticides near plants for butterflies. Learn to recognize larval and egg forms. That large green and black caterpillar eating your dill may one day turn into the gorgeous butterfly you were hoping to attract!

Butterflies, like all insects, are most active when temperatures are warmer. While moths are commonly found at night, most butterflies are active on sunny, warm days. Butterflies will benefit from a basking site where they can warm up on cool mornings. Add a light-colored rock or concrete garden sculpture as a basking site. Butterflies also need a source of water. A shallow dish of water or a depression in a rock that retains water is all they need.

The following types of plants are favorites of bees and butterflies, as well as being attractive additions to a yard and garden.

• Aster (Aster spp.)
  
• Azalea (Rhododendron spp.)
  
• Bee balm (Monarda spp.)
  
• Butterfly bush (Buddleia alternifolia)
  
• Butterfly weed and other milkweeds (Asclepias spp.)
  
• Cardinal flower (Lobelia cardinalis)
  
• Clover and other legumes
  
• Columbine (Aquilegia spp.)
  
• Coneflower (Echinacea spp.)
  
• Delphinium (Delphinium spp.)
  
• Fuchsia (Fuchsia spp.)
  
• Honeysuckle (Lonicera spp.)
  
• Jewel weed (Impatiens capensis or I. pallida)
  
• Lobelia (Lobelia spp.)
  
• Lupine (Lupinus spp.)
  
• Penstemon (Penstemon spp.)
  
• Phlox (Phlox spp.)
  
• Salvia (Salvia spp.)
  
• Trumpet creeper or vine (Campis radicans)
  
• Weigela (Weigela spp.)
  
• Zinnia (Zinnia spp.)
  

Before selecting plants for your yard or garden, it's a good idea to check with a local nursery about which species are most suitable for your area.

Source:
U.S. Department of Agriculture

Try Natural Pest Control with These Insect-Repelling Plants

If you're plagued by garden pests but want to avoid using pesticides, one natural pest control option is to choose plant species that repel pesky bugs. The following plants have their own chemical defense systems, and when planted among flowers and vegetables, they help keep unwanted insects and other garden pests away.

Pest	Plant Repellent
Ant	mint, tansy, pennyroyal
Aphids	mint, garlic, chives, coriander, anise
Bean Leaf Beetle	potato, onion, turnip
Codling Moth	common oleander
Colorado Potato Bug	green beans, coriander, nasturtium
Cucumber Beetle	radish, tansy
Flea Beetle	garlic, onion, mint
Imported Cabbage Worm	mint, sage, rosemary, hyssop
Japanese Beetle	garlic, larkspur, tansy, rue, geranium
Leaf Hopper	geranium, petunia
Mexican Bean Beetle	potato, onion, garlic, radish, petunia, marigolds
Mice	onion
Root Knot Nematodes	French marigolds
Slugs	prostrate rosemary, wormwood
Spider Mites	onion, garlic, cloves, chives
Squash Bug	radish, marigolds, tansy, nasturtium
Stink Bug	radish
Thrips	marigolds
Tomato Hornworm	marigolds, sage, borage
Whitefly	marigolds, nasturtium

Source:
U.S. Department of Agriculture