Pecan Phylloxera & Planting Field Corn

Karen Cambre, Sharpe, Kenneth W.  |  3/13/2018 2:19:53 PM

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News Article for March 12, 2018:

It has still been too wet to accomplish much in the planting world. Thankfully, trees and grasses are greening up and that helps to pull moisture from the soil and dry us up quicker than winter.

Pecan leaves have not emerged as of my writing. They are one of the last plants to put on leaves in the spring and therefore many of us from a rural background look to the emergence of pecan leaves as the true beginning of spring.

The timing of pecan leaves is important for more than predicting spring. It is the time of year that you can control pecan phylloxera. Pecan phylloxera are insects that cause galls in pecan trees. You may not know the insect, but many of you call me each May to say you have black knots all over your pecan leaves and twigs. These galls or knots are the result of the insect.

It is impossible to control pecan phylloxera once you see the black knots. The only time you can have a positive impact on damage is right at bud break. So you will need to keep a watchful eye out because your window of opportunity is very small.

Pecan phylloxera overwinters in the pecan tree, so if you had pecan galls last year, you will probably have them again this year. They survive in the cracks and crevices of the bark of the tree. When buds are formed on the tree in the spring, the insects will emerge to feed on the foliage and a gall is formed around the insect. This will appear on the leaves and twigs as a green gall or ball, but most people will not notice this stage because it is the same color as the leaves.

The phylloxera will lay eggs within the gall. As warmer temperatures approach in May the galls will turn black and crack open to allow the next generation of the phylloxera to emerge from the gall. This generation of insects does not damage the trees it only keep the species alive.

In order to prevent galls on pecan trees you will have to spray the trees when the buds begin to open and approximately ½ to ¾ inch of new growth begins to appear. Homeowners can spray with Malathion. Commercial producers can treat with Provado, Lorsban, Warrior or Admire.

You will find that all of the pecan buds and leaves do not open on the same day. For this reason I would suggest that after you make your first application, follow up with a second insecticide application 7 days later.

As we have seen this year, spring can advance quickly with warm temperatures so if you are planning to spray to prevent pecan phylloxera, check your trees daily and be ready to spring into action. You also may find that different pecan varieties will leaf out at different times.

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Rain has delayed plantings, but if you want to plant field corn this year, get it in soon. In south Louisiana optimal planting dates are usually from February 25 to March 20. You can plant later, but you start to reduce potential yields by ½ to 1 bushel per day past the last optimal date.

Field corn is planted to get a number of plants per acre. A good stand is 27,000 to 30,000 live plants/ acre. If you assume 80% plant survival, plant 33,750 to 37,500 seeds per acre. This kind of recommendation is made since each variety of corn has a different seed size. Farmers have to buy a specific planting wheel for each corn variety.

For those of us who think smaller, it will take approximately 12 to 20 pounds of corn seed to plant an acre, depending on variety. Spacing should be about 8 inches apart and seed planted at a depth of about 1.5 to 2.0 inches.

For more information on these or related topics contact Kenny at 225-686-3020 or visit our website at www.lsuagcenter.com/livingston.

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