Posts tagged insects

Gnat Attack

   If you’ve spent any time outdoors this spring in Eastern Iowa, you’ve probably seen them. Swarms of black flies –most people call them gnats – that surround their victims in a frenzied cloud.

   Bug experts say there’s not much you can do to protect yourself against black flies. The pests come out during the day; while mosquitoes come out toward evening, so you can either lock your doors and stay inside or put up with the huge welts they’ve been known to leave. See story here: http://tinyurl.com/mnqwen

    Removing the gnats’ habitat can reduce their population, as well as the number of mosquitoes, which start to appear about the time the gnats die. Linn County Public Health  monitors for mosquitoes, which carry risk of diseases such as West Nile virus. Residents can report bad infestations to the health department at (319) 892-6000. Workers are using larvicide to control mosquito larvae in standing water, but the same can’t be used against black flies, which live as larva in fast-moving water such as rivers.

   Both insects made my top 10 list of bad bugs: https://cindyha.wordpress.com/2009/05/22/bugged-by-bugs/

  What makes your’s?

Leave a comment »

Bugged by bugs?

  

Japanese beetles

Japanese beetles

 Spring in Iowa is too fleeting. Rare are those 70-degree days with cool nights before the air explodes with humidity and bugs begin their annual invasion. I can look at healthy green potato plants today and know that in a week or so the Colorado potato beetle will begin its defoliation quest. Same is true of the lush rose bushes that succomb ever earlier to the dreaded Japanese beetle, a copper-colored foreign invader.

   Because of the devastation they wreak on my plants, the Japanese beetle and potato beetle rank number one and two on my list of “bad bugs.” I was enjoying my backyard garden last night trying to think of others when a mosquito bit my leg. Mosquitoes= #3.

Colorado potato beetle

Colorado potato beetle

   Here are the others: 4) gnats or whatever those little black bugs are that bite behind the ears. 5) chiggers – not an insect, but larvae of a specific family of mites – the Trombiculidae. If you’ve ever suffered through chigger bites, you’ll know why these are on my list. 6) wasps – I try to leave them alone, but they seem ubiquitous this year and more aggressive – building wherever they take a liking, which includes my back porch and my sons’ club house.  7) ticks – again, not an insect, but my general worry over them keeps me from enjoying the outdoors at times. 8) Ants – luckily we don’t have  fire ants like they do in the south, but they’re just a pain when they decide to come in the house. 9) termites – again a general anxiety thing. 10) Emerald ash borer – not here in Iowa yet, but a preemptive disdain for a foreign invader that will someday devastate our ash trees. 

Emerald ash borer

Emerald ash borer

   What makes your list? I’m sure I’ll think of more, now that our perfect spring days are in the past.

Comments (7) »

Spring tree care

The following is by Linn County Master Gardener, Claire Smith:

 

    March marked the start of our transition from winter to spring.  Now that the snow has melted  (we hope,)  it’s a good time to examine your trees for winter damage.  We often expect our trees to be self sufficient and  tend to neglect their well-being.  

     After the frost is gone, thoroughly water trees that have been subjected to de-icing compounds.  This will move the chemicals through the soil and away from the tree roots.   Watering before the ground thaws will create runoff and pollute soil and ground water. 

     If your trees need to be fertilized, wait until the ground has completely thawed.  Fertilizer run off wastes money and also contributes to groundwater pollution.

     If, and only if, an insect problem exists, dormant oil sprays can be used once the temperature reaches a constant 40 degrees.  Dormant oils are used to control some scale insects and overwintering insects. 

    Rabbits and voles girdle trunks at the base.  Damage will appear as a lighter area on the trunk, primarily as teeth marks.   The damage interrupts the flow of water and nutrients to the roots.   While you have no recourse for the damage, it is wise to monitor the health of the tree as severe damage can kill a tree.

    Tree wraps should be removed in the spring as the temperature warms.

    Complete pruning prior to trees leafing out.  Storm damaged branches should be removed as they occur. 

    If you’re planning on adding trees to your landscape, now is a good time to visit our local nurseries and greenhouses for suggestions and recommendations.        Personally, I’m going to find the shadiest spot under the big walnut to plant my chair and enjoy my favorite summer beverage.

 

Leave a comment »

Firewood pests

 The following is from  Linn County Master Gardener, Claire Smith:

 

   Are you ready for the cold weather?  It’s been just plain chilly the past few mornings!  Does it make you think it’s time to get wood ready for your fireplace?  Is there a better way to spend a snowy day than with hot chocolate, a great book and a toasty fire? But, beware of bugs!  While the Box Elders and Beetles seemed not as prolific this summer, be careful you’re not transporting a host of other multi-legged critters along with your fire wood.

    Firewood is best kept out of the weather. Store it in your garage, a storage shed, or at the least protected under a roof. Whether you have your firewood delivered or chop your own, it’s a good idea to keep the wood up off of the ground.  Firewood holders with metal legs are wonderful as it is difficult for the insects to crawl up into the wood.  Insects will often seek a moist area to reside, so if a metal holder is not probable, at least use wood pallets to get the wood off the ground allowing it to dry and preventing rotting.

    To minimize the number of insects coming into your home, let the firewood you will use in one or two days set outside in the cold for one or two days prior to moving it inside as insects need a couple of days to warm up before becoming active   Never, never use insecticide on your firewood.  There is really little benefit to treating the wood, plus you create a potentially dangerous situation with vapors emitted into your living room. 

    Long horned beetles, metallic wood-boring beetles and bark beetles attack dead and dying trees.  Pillbugs, centipedes, millipedes and ground beetles are the most common insects found in firewood.  These insects are basically just a nuisance. None are harmful to you or pets so when you  see an occasional insect emerge from the wood in your house simply remove it from the premises, then enjoy the ambiance you’ve created.

 

Leave a comment »

Overseeding lawns

Richard Jauron, Horticulture Specialist at Iowa State University Extension, offers the following on overseeding lawns:

Healthy, well maintained lawns are attractive landscape additions.  Lawns in poor condition, however, are somewhat unsightly.  The poor condition of a lawn may be due to poor management, heat, drought, diseases, insects or other factors.  In severe cases, the existing lawn may have to be destroyed and a new one established on the site.  Lawns that contain over 50 percent desirable grasses can often be improved by overseeding.  

Overseeding is the sowing of grass seed into an existing lawn.  In Iowa, the best time to overseed a lawn is late summer (late August to mid-September).

Site Preparation

Good site preparation is necessary for successful overseeding.  If possible, identify and correct the problems causing the lawn to decline.  Overseeding may only be a temporary solution if these problems are not corrected. 

To reduce the competition from the established turfgrass, mow the lawn at a height of 1-1/2 to 2 inches.  Successful overseeding also requires good seed-to-soil contact.  Simply throwing or broadcasting seed over the lawn typically results in poor seed germination as much of the seed is resting on the thatch layer or soil surface.  Rakes, core aerators, vertical mowers, and slit seeders can be used to ensure good seed-to-soil contact. 

Overseeding Small Areas

Small areas can be prepared by gently raking the thin spots.  When raking, it’s necessary to break the soil surface without pulling out the existing turfgrass.  After raking, sow the seed by hand.  Then, work the seed into the soil by gently raking the areas a second time. 

Overseeding Large Areas

Large areas can be prepared by using a core aerator.  Core aerators are machines with hollow metal tubes or tines.  They remove plugs of soil when run over the lawn.  To prepare the site, go over the lawn three or four times with the core aerator.  When finished, there should be 20 to 40 holes per square foot.  Apply the seed with a drop seeder.  Afterward, drag the area with a piece of chain link fence or drag mat to break up the soil cores and mix the seed into the soil. 

It’s also possible to prepare the site with a vertical mower.  When run over the lawn, the knife-like blades of the vertical mower slice through the thatch and penetrate into the upper 1/4 to 1/2 inch of soil.  One or two passes should be sufficient.  Afterwards, remove any dislodged debris from the lawn.  Sow grass seed over the lawn with a drop seeder.  Work the seed into the soil by again going over the site with the vertical mower. 

Large areas also can be overseeded with a slit seeder.  A slit seeder makes small grooves in the soil and deposits the seed directly into the slits. 

Core aerators, vertical mowers and slit seeders can be rented at many garden centers and rental agencies.  If you would rather not do the work yourself, many professional lawn care companies can overseed your lawn. 

Post Seeding Care

Keep the seedbed moist with frequent, light applications of water.  It’s usually necessary to water at least once or twice a day.  Continue to mow the lawn at a height of 1-1/2 to 2 inches.  Mow the lawn frequently to reduce the competition from the established turfgrass.  When the new seedlings reach a height of 1-1/2 to 2 inches, gradually increase the mowing height over the next several weeks.  The final mowing height should be 2-1/2 to 3 inches.  Approximately six weeks after germination, fertilize the lawn by applying 1 pound of actual nitrogen per 1,000 square feet.  

When properly overseeded, a thin, scruffy-looking lawn can be turned into a thick, lush lawn in just a few weeks. 

Comments (5) »

Exposed roots

The following is by Linn County Master Gardener Claire Smith:

 

Ouch!  Ouch, again!   Oh! The sound is definitely not music to my ears.  How much damage did I do to the blades that I didn’t want to replace until season’s end?  Have you ever inadvertently mowed over a tree’s exposed roots?  Those are the surface roots growing just a little above the soil.  They are important to the support and health of a tree.  Continual wounds from a lawn mower blade or weed whip create entryways for insects and diseases. 

Here are some hints for easily eliminating a stressful situation:

§  Do not try to correct the situation with an ax!

§  Use mulch (one of my favorite items).  A two or three inch layer is attractive and provides a good environment for the roots.  Prevent smothering the tree trunk by keeping the mulch two or three inches away from the trunk.

§  Plant a shade loving perennial ground cover around the base of the tree.  The plants will insulate the roots but won’t out-compete the tree for water and nutrients.   Try some of the hundreds of varieties of Hosta that are just waiting to be chosen.

§  If you like some grass under the tree(s), strategically space plantings. 

§  Plan for a bit of elbow grease as weed control is critical. 

§  As a last resort, you could eliminate all of the grass by covering it with layers of newspaper.           

§  Do not build a raised bed around the tree.  Burying the tree roots will kill many species of trees.  And, the roots that don’t die will eventually reach the surface again.

§  Do not rototill or add soil to the planting area.

§  Amending the soil with organic materials such as peat or compost is very acceptable. 

There is still time to plant this summer. Change the landscape under the tree and save that mower blade and weed whip string for necessary areas. 

 

 

Leave a comment »

Oak Wilt Alert

The following is from Master Gardener Gene Frye about the revised “no prune” period for Iowa oak trees: 

  ISU Extension Foresters have just expanded the recommended “no-prune” period for Iowa oak trees to extend from March 1 through October 31 in order to minimize the chances of contracting the oak wilt disease.  The previous recommendation for not pruning was from mid-March through August.

 Oak wilt, a fungus disease, is fatal to all oaks in the red oak family within one year of the onset of the first symptoms, but white oaks may live for several years, and some even recover from the disease, but with substantial damage. 

 The main method of contracting oak wilt is through pruning or other wounds made during the growing season, with the resulting sap attracting certain insects carrying the oak wilt fungus on their bodies.  These insects bore into the wound carrying the fungus spores with them. 

 The other method of spreading oak wilt is through root grafts of nearby oaks of the same species.  Root grafts allow trees to exchange body fluids, so to speak.  Since the roots of most trees extend out to about the height of the tree, trees nearer than about one hundred feet of an infected tree of the same species can also acquire the disease.  Red oaks will not root graft with white oaks. 

If oaks must be pruned during the no-prune period, for example to manage storm damage, the pruning wounds should immediately be covered with a mixture of an outside white latex paint diluted one-to-one with water.  This is one of the few circumstances in which Extension Foresters recommend use of wound dressings.

 The first symptoms of oak wilt are a general drying and falling of leaves, usually during June or July.  In the case of red oaks, the whole tree is usually affected, but on white oaks, only individual branches show symptoms the first year of infection, followed the next years by more branches being affected.

  Positive diagnosis of oak wilt requires a laboratory test, but a reasonably reliable diagnosis can be made by finding longitudinal brown streaks just underneath the bark on affected branches.  Unfortunately, there are several other ailments that can appear to be oak wilt. Oak wilt usually appears in clumps, and is not nearly as devastating as chestnut blight or Dutch elm disease.  Infestations can usually be contained by application of good management practices. 

For more detailed information on oak wilt, see Extension publication SUL 15, “Oak Wilt—Identification and Management,” which is available at County Extension Offices for $1.00 or can be downloaded free of charge on the Internet at:  www.extension.iastate.edu/store  

Comments (1) »