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Thursday, August 13, 2015

2015 Sugarcane Aphid Efficacy Trial – 7 DAT Counts



2015 Sugarcane Aphid Efficacy Trial – 7 DAT Counts
               
                The sugarcane aphid continues to amaze in a startling way across the region.  Today I recommended treatment on the last of our scouting program fields that had been thus far untreated.  That makes 100% of our participating grower’s sorghum fields across Hale, Swisher, & Floyd that has reached the action threshold for at least their first treatment.  The pattern of these fields seemed to go from 1-2 sugarcane aphids per leaf across the field to 48.9 – 128.9 aphids per leaf across the field in 10 to 14 days.  With so much unknown about this new aphid to the area and products untried in the region, all new information should be shared with consultants, industry, and producers as soon as possible.  Yesterday we made our 7 days after treatment in our trial field just east of Hale Center. 


                For this trial, we have teamed up our program with our district entomologist from district 1 and 2, Dr. Pat Porter and Dr. Ed Bynum, Syngenta, and Bayer Crop Science.  Shared with you today are varying rates of products currently recommended or labeled for sugarcane aphid control.  Unfortunately, we had a SNAFU and misunderstanding in dealing with unfamiliar partnering equipment, GPA output, and chemical calculations that through this trial off with a 16.7% lower rate than what was intended for each treatment.  Actual applied amounts are shared here. 
                Data consists of 5 randomly selected plants from each small plot where we counted all aphids on one lowermost green leaf and one upper leaf (second leaf below flag leaf) from each randomly selected plant for a total of 10 leaves per plot.  This trial is an RBD and has 4 replications.  Due to noted differences in control between the upper leaves and lower leaves, we have calculated differences in aphid numbers in terms of upper and lower leaves in addition to total aphids averaged per leaf. 






                The ineffectiveness of controlling the aphids on the lower leaves in this trial should be chalked up to coverage.  The row spacing in these plots is 32 inches.  These plots were treated with 16.5 GPA and all treatments were applied with 0.25% NIS as a surfactant and still we did not seem to penetrate the canopy enough to achieve control on the lower leaves.  This matches what we are seeing in treated fields also.  I have been in contact with several independent crop consultants indicating similar findings in their area fields.
                Russ Perkins, Bayer Crop Science, is recommending changing adjuvants to an COC, something with silicone or something heavier to help penetrate down into the canopy to get at those lower, aphid covered leaves.  Monti Vandivier, Syngenta, seems to agree, “It’s all about coverage right with this aphid right now.  We need to penetrate that canopy and cover the entire infested area.  In my trials, I have been using Dynamic and getting decent penetration… at least on 40 inch rows… Controlling this sugarcane aphid reminds me a lot about fighting heavy spider mites in corn.  We need a good MSO or something heavy to pull those treatments down.”
                Today Russ told me, “Adjuvant choice with Sivanto should not impact the product quality… We just need it as deep in the canopy as we can get it.”
               

Special thanks to Dr. Pat Porter for making these graphs while I was in the field today!!!

Blayne Reed


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