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Extension Update by Gary Zoubek [May 10, 2012]

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Cropping Update/Nebraska Weather

Planters have continued to make great progress and we can now row many of the corn fields!  We received only .35” of rain the past week, but we also did not have any major storms or run off events, it sure all soaked in!  Thanks for Jerry Stahr’s help we got the RoundUp Ready Soybean Variety Comparison Plot planted.  It’s located just West of Jerry farmstead.  We planted it last Thursday at 130,000 seeds/acre.

As I mentioned last week, I cleanup up a couple of ETgages and set them out and have started taking readings at a couple locations East and South of town!  This past week we had high temperatures in the mid 90’s, mid 80’s as well as the 70’s!  So as the saying goes in Nebraska, wait a day or two and the weather will change!  We also had days when the wind speed averaged over 10 mph for the 24 hour period.  Also had considerable humidity a few of the days!

The two ETgages I put out averaged around 1.5” for the week!  If your corn crop was near tasseling the crop coefficient would have been 1.1, so to estimate the crop  ET we would multiply 1.5” x 1.1 which equals 1.65” for the week or .23”/day, but most of early planted corn is in the 2-4 leaf stage, the crop coefficient would be .1 or .18 so the water use for the week would have been between .15” – .27” or .02” – .04”/day!  As the continues to grow the crop coefficients also will continue to increase up to a factor of 1.1.

Each week I will try and share what the ETgage updates.  I’m also going to be watching an ETgage that has a grass cover so that I’ll be sharing estimates of ET for well water grass.

For more info about ETgages and how to use them, check out the NAWMN website: http://water.unl.edu/web/cropswater/nawmdn  we have a have a checklist for using the ETgage as well as information about ETgages or atmometers!  Megan Johnson did a nice news story on this ETgages.  It’s posted at: http://www.1011now.com/nebraskacentralnews/home/headlines/ETgages_Help_with_Irrigation_Management_Water_Conservation_150105015.html.

Next week I’ll share some info about using soil water sensors to better estimate the amount of water you have available in your soil profile!

Yard and Garden

I’ve also received a few calls about pine trees turning brown and dying.  If it’s occurred rapidly, I’d suspect a pine wilt which affects Austrian (long needles groups of 2) and Scotch pines (short needles in groups of 2).  These two pines are non-native trees while the nematode is native.  Ponderosa pines (long needles in groups of 2 and 3) are native to Nebraska; they don’t seem to be affected by pine wilt nematode.

Pine wilt is caused by beetles carrying pine wood nematodes vomiting them into the water-carrying vessels of the tree (xylem). The tree senses the nematodes and essentially blocks water to those branches. Often you will observe a branch then perhaps a side of the tree and eventually complete death of the tree within a few months.

Before you cut down a tree, a potentially infected tree, collect a sample of 4-6” in length and 1-2” in diameter and bring it into our office.  Jenny Rees, a coworker who lives in York and works out of Clay Center, will run a test to see if the samples has pine wilt nematodes.  We don’t have any cure for pine wilt, but sanitation is suggested.  Trees that die between May 1st and October 1st should be removed and the burned, buried or chipped.  Don’t hold the wood for firewood because the beetles can still emerge from the wood!  For more information about pine wilt check out our NebGuide at: http://www.ianrpubs.unl.edu/epublic/live/g1899/build/g1899.pdf.

I mentioned it last week, but I’m going to mention it again this week! Another insect to be looking for earlier than normal are bagworms.  This pest typically feed on juniper, spruce and pine trees, but can also feed on deciduous trees.  They produce bags that kind of look like Christmas tree ornaments, but they’re sure not that.  These brown bags are small one to two inches long and are made up of the needles from the trees they’ve been feeding on.  They can contain between 300-1,000 eggs.  We suggest removing as many of these bags as possible by the end of May and this year we may want to move that up a few weeks!  It’s important to destroy these bags, if you just place them on the ground, eggs may hatch and larva crawl back to the plants after hatching.

Timing is everything when trying to control bagworms.  Applications need to be aimed at the young larvae that typical hatch in mid to late June.  A copy of our bagworm control NebGuide can be found at:   http://www.ianrpubs.unl.edu/epublic/live/g1951/build/g1951.pdf.

I’ve also received a few calls on trees that may have some other diseases, environmental or herbicide drift as well as a few turf questions.  Typically we don’t need to water our turf in April or May, however we typically don’t have to mow cool season grass starting in March?  Blue grass has a shallow root system, and we have not received a lot of moisture the past few weeks, and as a result I’ve seen some drought stress in turf!  If this keeps up, it could be a long summer, but it’s Nebraska, we’ll see what happens this week!