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Tuesday, May 3, 2016

Droughts' impact on crops

Wednesday, June 20, 2012

Conditions have worsened and the question on everyone's mind is, "When will it rain?"

If anyone can accurately answer that, they would be a hero, especially if they said it would be within the next few days.

Recently, the Purdue University Agronomy Specialists provided the Ag and Natural Resource Educators with an update on the impact of drought on crops around the state.

Here is some of the information they had to share.

Thus far, the corn has been hanging on amazingly well, except in some of the counties where the drought is most severe and on the sandier soils. There has been some delay in silk emergence in regions where the drought is more severe.

When looking at the corn, one of the first symptoms of water stress is the rolling of the leaves to reduce transpiration in the afternoon.

If you go back the next day in the morning, the leaves will be unrolled and look better.

That type of stress does not indicate severe yield loss.

Once you see the symptoms get worse (leaves do not unroll), is when the drought stress is more severe.

If it stays dry and temperatures increase, the impact of the drought will be more severe.

This year's soybean plants are putting more energy into root development than on above ground plant growth.

Some of the worst looking fields right now are those that were planted in mid-May and didn't really have adequate moisture when planted and immediately after planting.

Overall, fields planted before mid-May are in good shape.

Soybean plants have the ability to recover from this dry period and still yield well if we get moisture later in the season.

So far, most of the yield losses that have occurred are in fields where farmers did not get a good plant population.

One thing to note is that this year, it will probably not be uncommon to see soybean plants under stress flowering at the V3 to V4 growth stages instead of R1 or R2.

It might be hard to control lambsquarter and marestail this year if it gets to be 4-inches or more in height and under drought stress.

If you see that you have lambsquarter or marestail in your soybeans, then you need to apply a post emergent herbicide.

It is suggested that under this year's conditions, you use the maximum rate and an adjuvant package designed for high temperatures and stress as noted by the herbicide label.

You should also be on the lookout this year for spider mites in soybeans.

Dry weather conditions can bring on spider mite damage fairly quickly.

Initial scouting for this problem can be done by looking for soybeans leaves turning a rust color.

If you see rust color leaves, then you should place a piece of white paper below the leaf and shake the leaf.

If tiny reddish or orange mites fall into the paper, you have a spider mite problem.

As soon as you notice the spider mites, you should spray to control them.

It is important you spray within a few days as spider mites can move throughout a field, causing damage very rapidly.

We should not worry at this time for spider mites in corn. However, if it gets even drier than before, then we have to start looking for the spider mites there, too.

As always, if you have any questions or would like information on any agriculture, horticulture, or natural resource topic, then please contact your local Purdue Extension Office at 448-9041 in Clay County, or 812-829-5020 in Owen County, or reach me directly at smith535@purdue.edu.

Purdue University is an equal opportunity/equal access/affirmative action institution.

Upcoming opportunities available to you through Purdue Extension include:

* June 26 -- Rabbit Workshop, Owen County Extension Office, 6:30-8 p.m.,

* June 26 -- Soil Health Workshop, Gosport Community Building, 9 a.m.-noon. $5. Call 765-653-5716 Ext. 3 to register,

* June 28 -- Morgan County Pond Field Day, Morgantown, 6-9 p.m. Call 765-342-1010 for more information,

* June 28 -- Sheep and Goat Parasite/FAMACHA Workshop, Dubois, 4-7 p.m. $25. More information and registration forms are available at http://www.ansc.purdue.edu/SH/, and

* June 29 -- Beginning Meat Goat Workshop, Dubois, 9 a.m.-4 p.m. $50. More information and a registration form is available at http://www.ansc.purdue.edu/SH/.