Sugarcane Aphid Update &
2015 Sugarcane Aphid Efficacy Trial – 14 DAT Counts
The sugarcane aphid (SCA) is still having a heavy handed impact on the region. In the field it does seem we are performing better in terms of knockdown and control with our treatments with several factors playing key roles. The adjusted action threshold seems to me a better fit for the High Plains and hits these prolific aphids before they get their population built up too high. Producers, consultants, and applicators seem to have a better understanding of the coverage needed via air or ground (air - 5 GPA minimum, 10 GPA preferred / ground – 15 GPA minimum, 20 GPA preferred) and the change of adjuvants to something heavier, such as an MSO or silicone based product, to better pull the treatment down lower into the canopy for control on the lower portion of the plant.
On August 19, 2015 we gathered our 14 DAT counts from our SCA Efficacy Trial. I have just now had the time to get the data analyzed and this information released. 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. Despite using 16.5 GPA, a standard rate of 0.25% NIS was utilized as an adjuvant, a standard practice for all treatments applied in this area and what was recommended for this research protocol. We did not get good control on the lower leaves and no differences were found on those leaves. This is one of the factors that lead us to recommend an adjuvant change with company agreement for all commercial applications. For this trial, continuing to count the lower leaves was proving pointless and quite time consuming. As a result we opted to only count the upper leaf for the 14 DAT counts. This upper leaf is actually the second leaf below the flag leaf.
Questions about rainfastness
Questions about the rainfastness of these two leading products Transform and Sivanto are common this season. All I can speak of is this trial and what appears on the company label, which might not be mentioned specifically. In addition, there are questions about Transform’s performance in this trial.
Applications for this trial were made on August 5, 2015. Treatments began with the low rate of Sivanto at 9 am and continued down the treatment list until Lorsban was applied at 11 am. We then gathered our pretreatment aphid counts in the untreated border rows from each plot. Almost immediately following our leaving this trial location, a heavy 0.75 inch rain began at 4:15 pm.
Dr. Mike Lovelace, Dow, toured this trial with us as we made our 14 DAT counts. Quoting from our discussion with Dr. Lovelace, “This is a good trial and I can see the differences it is showing… This is the first instance with Transform I have seen that control that was not a premium and I feel we have a stronger product than this… The rates are off due to the mistake in calibration, but all treatments are off the same… There must be some outside reason for Transform’s lackluster performance here… The trial methodology is strong and there is no research bias here but right now I am looking at the rainfall that occurred after treatment on these plots as the culprit.”