Pecan Weevils

Pecan weevil larvae. Photo courtesy of USDA Cooperative Extension Slide Series, Bugwood.org.

Pecan weevils are one of the most serious pecan pests for the home owner.  If you have ever opened a pecan to find a small white worm inside it, you have seen the larva of the pecan weevil.  The adult pecan weevil is a light-brown or grayish beetle with a long beak.  The beak of the female is longer than the body.

The adult weevils emerge from the soil from August through September, frequently after rains of 1 inch or more.  Adult pecan weevils feed on green nuts causing some green nuts to drop.  The more serious damage is caused by female pecan weevils drill holes in nuts and lay eggs.   The resulting larva feed within the nut.  After the pecans fall to the ground and the larva chews their way out of the shell and burrow into the soil.  They will remain in the soil for 1 or 2 years before emerging as adults to continue the cycle. 

Since the lifecycle of pecan weevils can span three years, control requires consistent treatment.  Good orchard sanitation and judicious spraying will help control this pest.  First, promptly sweep up fallen pecans from under the tree each fall and dispose of them.  This will help remove pecan weevil larva from the area underneath the tree. 

Secondly, consider spraying the root zone and trunk of the tree with an insecticide such as carbaryl when the adult beetles are emerging from the soil and moving into the tree canopy.  Start monitoring the beginning of August and spray when adult weevils are found.  Continue to monitor and treat as needed through September.  

Adult pecan weevil.  Photo courtesy of USDA Cooperative Extension Slide Series, Bugwood.org.

An easy way to monitor for pecan weevils is to wrap a burlap bag around the base of your tree several feet off the ground.  Adult weevils crawling up the trunk will be trapped under the burlap.  Daily monitoring will allow you to target your spray when the weevils are most active and it will provide a limited amount of physical control.  If you are handy, you can find information about building more intricate pecan weevil monitoring traps here:  http://pecankernel.tamu.edu/insect_update/weeviltraps.html

Garden Storage Ideas

The Onslow County Master Gardeners held their summer social last month and Nancy graciously hosted us as her home.  We had a great time socializing and enjoying Nancy's beautiful home and garden.  I particularly liked her neat idea for storing small items in her garden.

Nancy saw a discarded mailbox tossed in the ditch one day.  Instead of leaving it or throwing it in the trash, Nancy scrubbed it up, painted it and mounted it near her vegetable garden.  She dressed the mailbox up with some fun garden art and hung a basket from the support post.

 

Nancy uses the mailbox to store gloves, hand tools, seed packets and other items so they are protected from the weather and always handy when she needs them.  That's way better than my technique of carrying my pruners around in my purse.

I'd love to hear about your innovative garden storage ideas.

Heat Problems With Tomatoes and Vine Crops

--Carl J. Cantaluppi, Jr.
Extension Area Agent, Horticulture
North Carolina Cooperative Extension Service
Granville and Person Counties

When we experience high temperatures, we can expect some problems with vegetable fruit set and quality.  The ground around snap beans may be littered with aborted flowers.  Flower and fruit abortion are common responses to heat stress as a result of the general failure of successful pollination and fertilization.  The reproductive structures can become unreceptive, pollen can be killed, and the pollen tube may fail to form.

Many people are concerned most about their tomatoes and cucumbers.  In general, cucumbers are more heat tolerant than tomatoes.  Another problem can be a lack of female flowers, often noticed in summer squash.  As the heat increases, the ratio of male to female flowers changes to more male flowers.  When cooler weather returns, the plants will shift back to a more normal ratio.  

Female squash flower

Day temperatures over 90 degrees F. and night temperatures over 70 degrees F. reduce fruit set in tomatoes.  As few as 3 hours at 104 degrees F on two successive days may cause failure of fruit set.

Tomato problems related to heat stress on fruit set prior to the stress include sunscald and yellow shoulders.  Sunscald occurs when previously covered fruit are exposed to direct sunlight from having poor leaf cover.  

Solar yellowing (yellow shoulders) is a type of sunscald that occurs when lycopene (the red pigment in tomato) fails to develop in some varieties, leaving only the carotene (yellow pigment) to show at the shoulder where the dark green portion was.  This occurs when tissue temperature rises above 86 degrees F.  Even with temperatures under 85 degrees F., the surface temperature of exposed fruit can become high enough to inhibit normal red color development.

Symptoms of more severe sunscald are that the tissue starts off as a pale area of leathery dead tissue that becomes sunken, turning tan or light gray, later turning white, and dying.  Many times, the dead tissue will turn black from fungi that are feeding on the dead tissue.  This lethal sunscald occurs when tissue temperatures rise above 104 degrees F.  Damage usually occurs when fruits are suddenly exposed to sunlight.  This most frequently occurs after a harvest or a storm when leaves are moved around and fruit is exposed.  Over pruning can also increase sunscald problems especially with fruit in the upper part of the plant.  Good spray programs to ensure good foliage cover can reduce the problem.

Sunscald and yellow shoulders are most common in mid-summer when the sunlight is most intense and when temperatures exceed 85 degrees F.  Fruit that is sunscalded is edible but not if the scalded area has turned black with a secondary fungus.

Another problem in high temperature tomatoes is internal white tissue.  The white tissue is only noticeable when the fruit is cut.  The hard, white areas tend to be in the vascular tissues in the outer walls of the fruit, although it can also appear in the center of the fruit and in the cross-walls.  High temperatures during the ripening period seem to trigger the symptoms.  Sometimes there is a relationship with low potassium levels, which can be a problem in sandy soils and only rarely in clay soils.  Some varieties are more resistant to the problem, especially the very dark red varieties.

As always, and especially during hot temperatures, make sure that garden soils are wetted down to a depth of 6-8 inches.  Poke a long-handled screwdriver into the soil until it becomes hard to push.  Then pull it up and you can measure how deep the soil is wetted.  Then water until you reach that depth.  After gaining experience, you will know how long it takes to water your soil down to 6-8 inches, once the top of the soil starts drying out.

Problems with blossom end rot of tomatoes can be virtually eliminated by keeping the soil moist so the plant can take up calcium through the water stream.  Calcium deficiency in the developing tomato fruit causes blossom end rot, which is worsened by dry soils not allowing the calcium to be in the soil solution to be taken up by plant roots.

 

Adequate moisture prevents blossom end rot on tomatoes.

New Year Resolutions for Gardeners

The beginning of each new year is a time for looking back on the past, and even more importantly, forward to the coming year. It's a time to reflect on the changes we want or need to make and resolve to follow through on those changes.  As gardeners, there are steps that we can take to improve the ecology and sustainability of our landscapes.  Consider adopting one or more of these resolutions for your garden this year:

Plan your vegetable garden for year round production.  In most coastal counties, you can grow some sort of vegetable.  Careful planning will provide you with produce to harvest year round – reducing your grocery bills and your carbon foot print.

Incorporate fruit and vegetable crops into your landscape.  Fruit trees can function as ornamental trees or shrubs in the landscape while small fruits and even vegetables can be integrated into your sunny flowerbeds to add beauty and providing food too.

Choose plants and varieties that are low maintenance and easy to grow in our area.  Figs, muscadine grapes, rabbiteye blueberries and persimmons grow well in Onslow county.  If you must grow pears, choose a variety that is resistant to fire blight (a common disease in our area) such as Seckel, Moonglow, Kieffer or Magness. Avoid planting crops that will require a lot of pesticide sprays (like apples or many varieties of non-muscadine grapes) to produce a quality crop.

Commit to composting.  Composting is a sustainable way of dealing with garden waste and household food scraps that provides you with a valuable soil amendment and can reduce your fertilizer and pesticide inputs in the garden.  Use your compost to build your soil.  Soils that are high in organic matter store water and nutrients better, improving plant growth and productivity.

Minimize carbon-emitting inputs to the garden.  Gasoline-powered tools like lawn mowers and leaf blowers are obvious sources of carbon dioxide emissions but synthetic fertilizers and pesticides require a lot of energy to manufacture, package and transport.  Weed, prune and rake leaves by hand when possible.  Reduce pesticide and fertilizer use by choosing crops wisely and planting them in locations where they will thrive.  Rotate vegetable crops annually to reduce insect and disease pressures.  Test your soil and only apply nutrients that are needed.

Harvest, store and use your rainwater.  Use cisterns or rainbarrels to collect the water that runs off your roof – use this water first to irrigate your lawn, garden and container gardens. 

Minimize your watering needs.  Improve the water holding capacity of your soil by adding organic matter.  Mulch exposed soil in gardens and flowerbeds to suppress weeds and maintain soil moisture.  When designing new plantings, choose plants that will be drought tolerant after establishment (crape myrtles, Chinese and Japanese hollies, junipers, many bulbs, Mediterranean herbs such as sage, rosemary and thyme, and many ornamental grasses just to name a few).

Consider adding chickens, bees or other small livestock to your yard.  If you are up for the additional responsibility and commitment, chickens, ducks, guinea hens, rabbits or other small livestock help cycle nutrients in your garden.  Carefully managed poultry can help control insect pests and weeds while providing nitrogen and phosphorus to improve soil fertility.  Bees pollinate many of our vegetable crops – the loss of native pollinators makes the efforts of beekeepers even more important.

Whichever resolution you choose, I want to wish you and your garden a Happy New Year and a great growing season!

January/February Newsletter is Available Online Now

The January/February edition of my newsletter, In the Garden Now, is available online now.  Topics include:

*New Year Resolutions for Gardeners
*Add Winter Interest to You Garden
*Planning Your Spring Vegetable Garden
*Great Evergreens for Screens and Hedges

You will also find timely tips and tasks as well as information about our upcoming Master Gardener Volunteer class and our spring HELP Garden class.

You can find the newsletter here:  http://onslow.ces.ncsu.edu/content/In%20The%20Garden%20Now

Controlling Floriday Betony

Now is the time to control Florida betony.  This weed is found throughout the southeast and has the paired leaves and square stem characteristic of the mint family.  Florida betony is also known as wild artichoke or rattlesnake weed.  Both of these names refer to the distinguishing structure of Florida betony – the swollen white tubers that are produced underground.  These tubers resemble the segments of a rattlesnake’s tail or a white grub.  These structures are responsible for the persistent nature of Florida betony.  The tubers are also edible.

Florida betony is a cool season perennial weed.  It goes dormant during the heat of summer but grows enthustiastically in the cooler temperatures of spring and fall.  Control of Florida betony depends on the location – treatment in lawns is easier than landscape beds.  

Controlling Florida betony in lawns requires a multipronged approach.  In lawns, the first step to weed control is to optimize turf growth.  A dense stand of regularly mowed grass will compete better against Florida betony and other weeds.  Follow the correct cultural practices for your lawn to make it as thick and healthy as possible.  This includes mowing at the correct height and frequency, as well as  fertilizing at the right time and rate for your grass type.   Cultural requirements vary depending on the type of grass you have in your lawn.  For more information, request a lawn maintenance calendar for your turf type from your local Cooperative Extension Office.  

There are selective herbicides that can be used for control in lawns but the herbicide option will depend on the type of grass you have.  Herbicides that contain 2,4-D as the active ingredient work well on zoysia and bermuda lawns.  Centipede and St. Augustine are sensitive to 2,4-D.  For this reason, atrazine is frequently used to control Florida betony in these turfs.  That said, combination products that contain 2,4-D, MCPP and dicamba (Weed-B-Gone, Spectracide 33 Plus) can be used on St. Augustine and centipede lawns as long as the lower label rates indicated for the turf type are used.  When using any product, it is important that your sprayer be properly calibrated to apply herbicide at an accurate rate.  As with any chemical, make sure you read and follow all label directions.  Stay out of the border of shrub beds or the drip line of individual trees or shrubs in the landscape when using these products.

Regardless of the herbicide you use, you will need to make more than one application to achieve control.  It often takes two years to completely control Florida betony.  The best time to spray for control is in the fall as the weed is starting to grow for the season (October-November) and again in the spring (February-March). 

Controlling Florida betony in perennial beds is more of a challenge.  Pulling is not very effective since it leaves tubers behind in the soil.  If you are going to remove Florida betony by hand, dig carefully to remove the tubers.  This technique is effective in small areas.  Make sure that tuber-infested soil is disposed of carefully so the Florida betony doesn’t spread to a new area.  Do not compost the tubers.  Applying a thick mulch, 3-4 inches deep, can help slow the spread of Florida betony but will not control it completely. 

Glyphosate (RoundUp and other brands) can be used to control larger infestations in flowerbeds.  Glyphosate is a non-selective herbicide so it will damage or kill any plant it comes in contact with.  However, careful targeted spraying can provide control.  Spray only when there is little to no wind and air temperatures are less than 85 degrees.  Some spray nozzles come with a cone that be used to prevent drift.  Certain product formulations marketed to homeowners now come with a “foam” setting that helps reduce drift and allow you to track application better.  Glyphosate application is particularly effective when the Florida betony is in flower – typically in mid to late spring. 

The key to effective Florida betony control is good management, appropriate herbicide selection, accurate timing of application and persistence.

Brand names are included as examples only and are not intended as an endorsement.  Active ingredients may be marketed under many different formulation and brand names.

Trees and Hurricanes

Hurricane Irene was not kind to the trees in Onslow County.  During my post-storm inspection of the county I noticed a lot of trees that were down or damaged to the extent that they needed to be removed.  However, it was interesting to note that the majority of the damage was limited to a very small number of tree species.  Bradford pears and pecan trees definitely bore the brunt of the damage but there were a smattering of water oaks down as well. 

So what do we do now?  Many people are afraid of any tree in a hurricane but it is obvious that some tree species withstand these high wind events much better than others.  The University of Florida (UF) has done extensive research on tree survival in hurricanes.  This study looked at many factors that related to tree survival in hurricanes but today we are going to look at just one factor: species selection.  Some tree species are simply more resistant to wind than others.  It would be wise to take this fact into consideration when choosing trees for your property. 

Good trees for our area that show the highest level wind resistance based on this study include: American holly, yaupon holly, crape myrtle, southern magnolia, live oak, bald cypress, pond cypress, and sabal palm.  Those rated medium-high for wind resistance include: Japanese maple, river birch, ironwood, sweet bay magnolia, shumard oak and hickories.  Consider using these species to reduce future storm damage potential on your property.

Equally important to note is which trees fared most poorly in the UF study.  Common local landscape trees that showed the lowest wind resistance include: pecan, tulip poplar, Bradford pear, southern red, laurel and water oaks, Chinese elm, and Leyland cypress.  These species should be avoided in landscape plantings.  Pecans should be situated well away from structures and power lines.  Likewise, red and silver maples, sycamore, white and willow oaks, weeping willow, and American elm scored medium-low wind resistance so avoid these as well or use them only with caution. 

We will discuss how to assess a storm-damaged tree and other factors relating to hurricane-survival in future posts.  Meanwhile for more information about hurricanes and trees, check out the University of Florida’s site Trees and Hurricanes here http://hort.ifas.ufl.edu/treesandhurricanes/.