Bees: Angels of Agriculture

Remember when we were kids, running around outside with carefree abandon as we played our favorite games?  That is when we first became acquainted with bees.  We would unknowingly tromp through their little homes and nectar/pollen air routes, and receive our annual bee sting.  Bees became the bad guys.

But, as we have gotten older, we figured out how to avoid stings and understand they are really the good guys, called "Angels of Agriculture" by some.  And, for good reason!   Did you know that about one-third of the food we enjoy results from bee pollination?

Without bees, fruits, vegetables and nuts would not mature. The same thing is true about alfalfa and clover crops, which are needed by livestock (meat and dairy).  Bees also pollinate oilseeds and cotton crops.  And, then there is honey, which has rightfully earned its reputation as a whole food and medicine.  The list is long, and affects much of what we need to survive.

But wait!  Bees have other talents...they can be used as "sniffer bees" to locate explosives, drugs, and diseases.  Some scientists claim bees are better sniffers than dogs!  When bees are exposed to a specific smell and given a sugar reward, they stick their tongue out to receive it.  More specifically, trained bees are housed inside a hand-held detector. When they recognize a particular scent, like illegal drugs or bomb ingredients, they stick out their tongues.  The response is then recorded by computer software which identifies the substance.  

Regrettably, we are now learning that bees are having a rough time surviving in the modern world.  Bees have been around a long time and can withstand a lot of stress as long as they have nutrition resources and habitat.  Bee fossils, millions of years old, have been discovered.  Egyptian tombs are adorned with bee pictures; cave paintings of beekeeping exist in Spain dating back to 7,000 BC; and, the Roman Empire valued honey over gold as currency. 

Bees have had an amazing journey to have made it this far.  But, since about 2007, bees are being affected by a sort of perfect storm, consisting of parasites, varroa mites, pathogens, colony collapse disorder, poor nutrition (mono-crops, artificial nectar), pesticides, urbanization, and changing weather patterns.  They continue to die and disappear in larger-than-average numbers worldwide.

We are talking 4,000 species of bees, not just fuzzy honeybees.   They don't all make honey, but they are all pollinating dynamos, like the mason bee. 

You can help out in a big way by doing just a few little things: 

• Plant more single-petal flowers (blue, purple, pink, yellow).  Bees are insensitive to red.  A few of bee's favorites include: asters, anise hyssop, borage, clover, cosmos, crocuses, hyacinth, sedum, coneflower, Shasta daisies, dahlias, foxglove, geraniums, hollyhocks, hyacinth, marigolds, poppies, phlox, roses, snowdrops, sunflowers, blackberries, cantaloupe, eggplant, cucumbers, gourds, cherry trees, peppers, pumpkins, squash, strawberries, watermelons, bee balm, catnip, cilantro, fennel, lavender, mint, rosemary, sage, thyme, alyssum, black-eyed susan, butterfly weed, yarrow, Russian sage, marigolds, snapdragons, crepe myrtles, zinnias. 
• Plant in groups (3' x 3') - it's easier for bees to locate them and shortens distances traveled to collect pollen and nectar
• Plant flowers that bloom early (crocus, hyacinth, borage, calendula, and wild lilac) and in fall (zinnias, sedum, asters, witch hazel, goldenrod) - for continued food supply
• Bees are wild about dandelions!
• Try a patch of perennial wildflowers
• Vegetable garden
• Provide water (shallow plates/pans give them a landing strip) - near flowers, if possible
• Provide a little wet dirt or mud, for nest building
• Flowering hedgerows are meccas for bees, providing both food and shelter
• Clover patches delight bees, which withstand hot, dry conditions
• Pots and planters work well for smaller yards or balconies
• Pollinators are least active after dusk, making it best time to spray, if you must
• Seek out chemicals that do not harm pollinators
• Construct bee houses - the internet is full of inexpensive DIY ideas
• Amateur beekeeping, scaled down for backyards
• Engage kids in bee projects - get them educated and interested
• Share tips with others
• Note that these tips apply to all pollinators: butterflies, birds, wasps, etc.

Wouldn't it be great to know that your local bees are doing the "waggle dance", telling their fellow bees where your garden is every summer?

A few OSU Fact Sheets to learn more:

Honeybees, Bumblebees, Carpenter Bees, Sweat Bees (EPP-7317)

Nectar and Pollen Plants in Oklahoma (EPP-7155)

Africanized Honeybee in Oklahoma (EPP-7325)

Household Pest Control (EPP-7312)

Safe Use of Pesticide in Home and Garden (EPP-7450)

Fall Webworms: 

Now Holding Spinning Classes

Those ghostly nests over the ends of tree branches are fall webworm caterpillars.  Despite their name, they started spinning their nests in May.  Now, in late summer those nests are larger because the second generation of larvae have stripped the leaves down to their spines and have left ugly debris in our trees.

The bad news is the caterpillars are known to attack 88 species of Oklahoma trees.  And they enlarge their nests to encompass more leaves to eat as they only eat inside their protected nest.   This pest has two generations each year.  The second one (the one we are seeing now) is generally more visual and damaging.

The good news is that as long as the tree is established and healthy, it should survive and produce lush branches next spring.  Rarely do fall webworms defoliate entire trees. The caterpillars eat only the soft part of the leaves, and avoid the spine, twigs and branches so regrowth can occur.

Larvae and Moths

This pest overwinters as a pupa in a cocoon that is concealed in ground litter, cracks, and crevices in the soil. Adults first appear in mid May.  The females deposit eggs on the under-surface of leaves.  Larvae then hatch in seven days.  They immediately begin to spin their silken web over foliage.  Nests can grow up to three feet in diameter on an infected branch.  The larvae love each other's company and feed together in the nest until they mature into white moths.  The larval stage is the most destructive.

Management

With the exception of smaller tress during heavy infestations, most deciduous trees are able to withstand a feeding event.  Damage is mostly aesthetic, and control is not typically warranted except in the case of pecan orchards and tree nurseries.

Various species of natural enemies help to manage this native insect.  Birds and insect predators and parasitoids attack the larval stage.  Predators may also destroy eggs.

If the nest is within reach and you feel you must do something, we have a few suggestions:

Non-chemical:

If the webbed branches are within reach, they can be pruned and destroyed if the aesthetic shape of the tree is not compromised. 

If you don't want to prune but can reach the nest, you can break it up by hand with a broom or pole with nail sticking out.  Break up and destroy the webbing.  Hungry larvae will have to stop and re-spin their protective tent before they can eat again.

Chemical:

In serious cases, you can apply an insecticide labeled for webworms or defoliating caterpillars.  Push the applicator wand through the webbing so the spray will make contact with the worms and the leaves they eat.

If you decide to use an insecticide (and most people don't), consider using a safe organic insecticide such as Bt, as found in the brand Thuricide. It is widely available and is safe for you, your pets, and the good insects.  Other organics such as horticultural oil (Neem would be a good choice) and pyrethrin are recommended. 

Be sure to read and follow all label directions before each use to maximize efficacy, prevent phytotoxicity and minimize adverse environmental impacts.  Note the insecticide will not destroy the silky web which will remain in the tree until it naturally degrades during the following winter.

For severe infestations out of your reach, contact a reputable lawn service.

Mimosa Webworms -  double time spinners

A native of China, the Mimosa webworm can defoliate mimosa and honey locust trees.  Damage from their second and third generations can be severe and unsightly.  The insecticides mentioned above can be applied.  It is not advisable to make a large planting of mimosa or honey locust trees unless you make plans for chemical control.

Pesticide Effectiveness

Ever wonder why pesticides don't seem to quite as effective as they should be?  Well, there can be a number of reasons for this lack of efficacy. Here are some of the common ones:

     1. Lack of good foliage penetration.  This often is a problem when spraying for bagworms on junipers.  The spray must penetrate the foliage and reach the bagworms toward the inside of the plant.  High-pressure commercial sprayers are able to get the spray to the insects, but homeowner models are much more problematic.  With pump-up sprayers, you may have to push the wand through the outer layer of foliage to reach insects toward the inside of the plant.

     2. Not spraying where the insect is. Many of our insects and mites feed on the underside of leaves.  If the plants are sprayed over the top, little to no pesticide actually reaches the pests. This problem is often seen with spider mites on broad-leaf plants and cabbage worms on cabbage, broccoli and cauliflower.

     3. Maturity of pest. Insects become much more difficult to control when they become adults. For example, Sevin does a good job of controlling young, early instar grasshoppers, but is much less effective on adults.

     4. Level of disease pressure. Most fungicides are better used as preventatives than as curatives.  If a disease gets firmly established, it may be difficult to bring it back under control.  For example, chlorothalonil is effective in controlling early blight and Septoria leaf spot on tomato if used as a preventative.  However, chlorothalonil will not control these diseases on badly infested plants.

     5. Choosing the wrong product. Homeowners often use a product they have on hand.  However, products differ markedly in how well they control specific pests.  Make sure the pest you wish to control is on the label.  Unfortunately, even labeled products may vary in effectiveness.

     6. High pH spray water. Certain pesticides are not stable in high or low pH water. The following are some examples.

     * Captan has a half-life of 3 hours at a pH of 7.0, but only 10 minutes at a pH of 8.0.

     * Carbaryl (Sevin) has a half-life of 24 days at pH 7.0, but only 1 day at pH 9.

     * Diazinon is most stable in pH 7 water, with a half-life of 10 weeks; at pH 5, it is 2 weeks.

The half-life of a product is the amount of time it takes for half of the product to be neutralized.  For example, if you apply 3 ounces of a product to a gallon of water and the half-life is 8 hours, only half of the product is still active at 8 hours, one-fourth of the product is active 16 hours and 1/8 of the product is still active at 24 hours.  

If you do choose to use pesticides, be sure to always read and follow all label directions.

Q&A: My red-tipped photinia developed brown spots last summer.  I was told this is a fungus.  Is there anything I can or should do for prevention?

Like many plants that are densely planted in a community, they tend to get disease.  In this case, it is a fungus called entomosporium leaf spot.  This is manifested by red to brown spots on young leaves that may progress to cause extensive leaf drop.  It usually does not kill the plant, but impairs growth and appearance.

It starts in the spring, but may not be noticed until summer damage is apparent.  The fungus over-winters in the leaves fallen to the ground the previous summer.

Effective treatments involves cleaning up all of the old leaves from the previous year to rid the plant of disease exposures.  In addition, if you wish to go to the effort and expense, there are fungicides that are effective if begun before the disease is established.  OSU recommends several fungicides as preventatives.  Contact the OSU Extension Office for recommendations.