Although cotton producers thought that we would have until 2014 to come to grips with life without Temik, the March 18th announcement by Bayer CropScience to decommission production of methyl isocyanate (MIC) will force us to develop alternative strategies for insect and nematode management. So, what do we do. The following are some thoughts and suggestions for managing cotton nematodes in today’s crop without Temik.
Growers are going to be in one of these two categories:
- Those who took nematode samples last fall and know where their nematode problem fields (or areas within fields) are.
- Those who don’t have a clue if they have a problem or not.
Regardless of your situation, as the old saying goes, “today is the first day of the rest of your life.. Begin this year on your way to finding out – or staying current – on a field by field basis regarding nematode presence, identity, and severity. It is too late to sample for nematodes now, but you can start now thinking about the future.
If you do not have a current nematode assay report, you may be able to develop an educated guess based on the past yield history of the field and what the cropping history has been for the last 2-3 years. For example, sandy and sandy loam fields that were in cotton, soybean, or corn in any cropping pattern during the last 3 years are good candidates for a root-knot nematode problem.
However, if corn was grown in the field last year, there is little likelihood of a reniform nematode problem. On the other hand, if the field is a silt loam or clay loam then reniform nematodes are an ever-present danger if you farm south of I-40. Cotton monoculture will result in the highest nematode populations in these fields if reniform is present.
Soybean will also increase reniform nematodes, while corn will lower the population. Crop yield history is very important to factor into the equation as well. If the field was in cotton last year, was the yield acceptable, or was it “off” from what you would have expected. Use the same reasoning with soybean – how did the beans do. Should they have done better based on the inputs? If corn was grown, it will be hard to make a guess as to the nematode status of the field. Root-knot will increase on corn, but the nematode doesn’t generally cause a lot of yield suppression unless the population is extremely high.
There are a few options for nematode control in cotton. If you have Temik on hand , use it. In addition, three seed treatment packages are available with a nematicidal component: Avicta Complete Pak®, Aeris®, and Poncho-Votivo®. All three can help when nematode pressure is relatively low. None of them are going to provide satisfactory control when nematode pressure is high. Vydate C-LV® may provide supplemental nematode suppression as a post-planting foliar application shortly before pinhead square.  .
At the extreme are the pre-plant soil fumigants Telone II® and K-Pam®. These are excellent nematicides, but they are expensive and phytotoxic and need to be applied well ahead of planting. They also need to be injected into the row with specialized equipment.
In the absence of Temik, the following scenarios – with our suggested approach to nematode control may help.
SCENARIO 1: LOW TO MODERATE NEMATODE PROBLEM IS VERIFIED OR SUSPECTED.
Use seed treated with one of the seed treatment packages listed above. There is evidence that these material. can suppress nematode infection for a couple of weeks . if the pressure is not high. If root-knot is the issue, the use of a seed treatment on the only moderately resistant cultivar currently available (Phytogen 367 WNR) may improve nematode control. There are no reniform nematode resistant cultivars.
SCENARIO 2. MODERATE TO HIGH NEMATODE PRESSURE; HISTORICALLY HANDLED WITH 5-7 LB/A TEMIK.
Use a nematicide seed treatment and apply Vydate C-LV according to the label at or preferably shortly before pinhead square. Again, if root-knot is the problem, consider the resistant cultivar plus these treatments.
SCENARIO 3. SEVERE NEMATODE PRESSURE; FIELD WAS A “PROBLEM FIELD” LAST YEAR.
- Option 1: Rotate to something else.
- Option 2: Apply one of the soil fumigants.
Nematodes can be managed, but the good old days of applying Temik in-furrow at planting as the only nematode control strategy are over. Now, growers are going to have to use the same approach and concept that they are already using for their weed and insect control. They need to know where the problem exists, what nematode is involved, and how severe the problem is. Growers (or their consultants) have been scouting fields for years to determine these three things for insects and weeds. We need to do the same for nematodes…….the only catch is that nematodes are invisible so the scouting has to be done with a soil probe and bucket in the fall in preparation for next year’s crop.
For more information about nematode management in cotton, look to these fact sheet publications prepared by the University of Arkansas Division of Agriculture.