Japanese beetle monitoring traps confirm early season in 2012

As anticipated, Japanese beetles are out early this year.  The first beetles were captured in central Indiana during the week of May 14-18. (This is nearly a month earlier than most years.)  We expect Japanese beetles to arrive in full force in this area within the next 2-3 weeks. 

Because we have never experienced such an early spring, it is difficult to predict just how the beetle populations will respond.  We know that the beetles are active early but we do not know if this means that they will be with us longer into the summer or not.  Also, keep in mind that dry conditions do not favor beetle emergence but a significant rainfall event could potentially shift emergence into overdrive.

It is safe to say that we need to prepare now, however.

Protect susceptible plants, especially those that have been recently transplanted or those that are stressed for one reason or another. Favorites host plants for Japanese beetles include linden, crab apple, plum, and other fruit trees, rose bushes, grapes, and several garden variety vegetables. 

Grub preventative applications probably cannot be applied too early this year. The newer long lasting grub control products will be a great advantage this year because we do not know exactly how long the grubs will be feeding on the turfgrass.

If dry weather continues, oviposition and grub feeding may be concentrated in irrigated turfgrass.

With all insecticides, either for adults or for grubs, it is critical to follow the label directions exactly when making applications.  

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Time to Water?

With the heat and dry conditions most in Indiana are experiencing, many turf areas are starting to brown. Water is critical to the growth of all plants, not just turfgrass. Turfgrass leaves and shoots are comprised of about 80% water. A lack or water (rainfall or irrigation) will lead to a decrease in growth and energy production and an increase in plant stress. When turf has insufficient water it will begin to wilt. Leaves will roll or fold to conserve water by reducing their leaf area. The easiest way to determine whether or not turf is wilting is to walk across it. If you notice that your footprints don't bounce back right away, this is a sign the plant is drought stressed. Following these initial symptoms, plants will turf from a green wilted appearance to brown in colors as the leaves die (not the plant) and the turf enters a drought induced dormancy. 

Foot-printing is the first sign of moisture stress and can be spotted when the turf does not “bounce-back” after walking across it due to moisture stress and a lack of water.
Damage from mower traffic on drought stressed turf.

Notice how the turf is laid down here after the tires from the mower ran across it and the turf has not “bounced-back” due to moisture stress and a lack of water.

How should turf be managed during dry spells and drought?
When possible stay off the turf! Limit traffic (including mowing) to minimize crushing of the turfgrass leaves and crowns and causing damage. In order to keep your lawn green during hot and dry periods at least 1.0 inch of water will need to be applied weekly. However, with far less water you can keep your lawn alive. Water once every 2-4 weeks with ½ inch of water to keep turf plant crowns hydrated during drought. This amount of water will not green up the turf, but it will increase its long-term survival during long dry spells.

When irrigating it is best to irrigate early in the morning, but occasional watering at mid-day or early in the morning in order to prevent injury from moisture stress is allowable. Following wilt, turf should recover very quickly within a few hours. However, following drought (brown turf), turf will require at least 1-2 weeks after significant rainfall returns to recover.

Aaron Patton, Turfgrass Extension Specialist

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Grassy Weeds in Turf Planted Last Fall

Many samples have arrived in the Plant and Pest Diagnostic Lab the past few weeks with the common question of “What’s this grass in the turf I seeded last fall?”. Although there could be a host of answer to this question with annual bluegrass likely on the top of the list, most of what I have identified is either annual ryegrass or winter wheat. Annual ryegrass is a common ingredient in poor quality seed mixtures and winter wheat is commonly found in areas planted with wheat straw as a mulch. Both species should die during the warmer summer months without the need to apply a herbicide. Below are some pictures and helpful clues for identifying these grasses in turf that you plant.


Aaron Patton, Turfgrass Extension Specialist
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Don’t Forget to Sharpen Those Mower Blades

Sharply cut leaf blades increase turf health by improving recovery, decreasing water loss, and increasing photosynthesis. Lawns mown with a dull mower blade have poor aesthetics, heal more slowly and have greater water loss. Seedheads are present in many lawns right now and they are typically tougher to cut than the grass blades themselves. As such, it might help to switch to a sharp set of mower blades to help slice through these seedheads.

Homeowners should sharpen mower blades at least twice a year. To make this easy, buy two sets of mower blades and sharpen both sets each winter. Put a sharpened blade on before the first mowing and then switch when you notice that the leaf blades are becoming ragged in appearance as this is an indicator of a dull mower blade.

For professionals, consider sharpening mower blades weekly, bimonthly, or monthly depending on the amount of turf you are cutting. Again, inspecting the turf leaf blade is the best way to determine when your mower becomes dull.

Aaron Patton, Turfgrass Extension Specialist
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Assessing Spring Freeze Injury in the Landscape

As most gardeners have marveled, we're having one of the earliest "spring" seasons this year, with woody plants and herbaceous perennials three to six weeks ahead of "normal."

And then, perhaps inevitably, "normal" spring frost and freeze visited. Being so much further along in their development, plants are quite vulnerable to damage.


Home fruit-growers have reason to be concerned: At 28 F, you can expect a 10-percent loss of flowers/young developing fruit. However, at 25 F that loss increases to 90 percent! Here, in the Lafayette area, we hit 27-28 F last Thursday (April 12) morning, followed by 24-25 F Friday (April 13) morning - a double whammy.

Bud counts were exceptionally high until the freeze, so in some cases, even just 10 percent retained fruit might still be a decent crop on our tree fruits. Grapes may also still have ability to crop on shoots that have yet to emerge. Strawberries are a bit easier to protect through frost and freeze, but only if you took measures, such as using floating row covers, recovering with straw, etc.

However, it is only mid April, and additional frosts/freezes are still possible. Bottom line is that unless it is already a complete loss, we won't really know the rest of the story for quite a few more weeks. 
It is easy to check fruit buds for damage by cutting open the bud and looking for dark brown or black centers. Our Purdue Extension fruit specialists put together these videos to help you assess the status of your fruit plants.

Assessing Spring Freeze Damage to Apples
Video: http://youtu.be/YcSRg74Hb_A
Assessing Spring Freeze Damage to Peaches
Video: http://youtu.be/DcS2XGAqoFk
Assessing Spring Freeze Damage to Grapes
Video: http://youtu.be/lNUZu5Bx08M
Assessing Spring Freeze Damage to Strawberries
Video: http://youtu.be/F-QoX1C4_S0
Assessing Spring Freeze Damage to Blackberries
Video: http://youtu.be/EyIhvfY2apM

For ornamental trees and shrubs, plant response has been quite varied, depending on species, location and, of course, temperature and duration of that temperature. Susceptible plants may have wilted leaves, brown or black necrotic spots on leaves, or perhaps dieback of entire twigs. Plants that were in bloom likely have brown petals or dropped flowers entirely. Here are some links to articles from previous spring freezes that will give more information.

Note that freeze incidents are normal for this time of year. What is abnormal is the earliness of development, leaving the plants exceptionally vulnerable to freeze. The good news is that woody plants, in most cases, will outgrow the damage.

B. Rosie Lerner, Purdue Extension Consumer Horticulturist

Article originally posted at: http://www.agriculture.purdue.edu/agcomm/newscolumns/archives/YGnews/2012/April/120419YG.html
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