Standardized Evaluation of Insecticide Efficacy Against Sugarcane AphidS. Stewart, A. Catchot, D. Kerns, G. Lorenz, N. Seiter, D. Buntin, Alana Jacobson, M. Way. F. Reay-Jones, M. Jones, A. Zarrabi, Tom Royer, Kris Giles, J. P. Michaud, G. Nuessly, and R. Bowling
Design Replicated, small plot, RCB Application timing against threshold, rapidly increasing populations 5 Core treatments
◦ Check, Transform (1 oz), Sivanto (4 oz), Centric (2 oz or 2.5), Lorsban Advanced or Nufos (32 oz)
Only used data collected after a single application◦ Classified as 3-5, 7-10, 13-15 days after treatment
Optional treatments at researcher discretion◦ Tests were over-treated at discretion of the researcher for other pests (e.g., Besiege
or Prevathon) or to flare aphid infestation (e.g., pyrethroid)
Sampling of leaves (10 total)◦ Typically 5-10 lower/mid canopy and 5 flag leaves
Yield data were collected in several trials◦ But I’m only going to show one example
Analysis Used tests with the 5 core treatments for primary analysis
Response variable was average aphid numbers per treatment in each trial (blocked by trial)◦ 3-5, 7-10, and 13-15 DAT◦ Mid-canopy, flag leaf, and total (mid + flag)◦ PROC GLIMMIX using LS Means for separation (α = 0.05)◦ Square root transformation of data prior to analysis◦ Untransformed LS-means are presented
Comparisons of some “optional” treatments are included◦ Paired t-test of trial averages
Across All Rating DatesA bunch of data (21 tests, 61 test*date ratings)
NUMBER APHIDS PER LEAF PERCENT CONTROL
* Transform 1+ oz, Sivanto 4+ oz, Centric 2+ oz, Endigo 4 oz, Strafer 3+ oz
P = 0.0002
P < 0.0001
Numbers of Aphids in Check PlotsFor tests having 5 core treatments
Number of Trials
*
* Omitted from analyses
Numbers of SCA at 3-5 DAT
P < 0.0001N = 9 tests
Numbers of SCA at 7-10 DAT
P < 0.0001N = 12 tests
Numbers of SCA at 13-15 DAT
P < 0.0001N = 9 tests
Numbers of SCAAverage - Flag + Lower Leaf
A
BBBB
A
B
CCC
A
AB
BB
C
P < 0.0001 for all
9 Trials 12 Trials 9 Trials
Average Percent Control of Two Transform Rates within the Same Tests
12 TrialsP = 0.247
Paired, 1 tailed t-test of trial averages
a a
Average Percent Control of Two Sivanto Rates within the Same Tests
Paired, 1 tailed t-test of trial averages
a a
P = 0.065 P = 0.028
A B
(8 oz in one test)
Average Percent Control of Optional Treatments Compared with Check Plots in the Same Tests
(Number of trials)
* P < 0.05 (paired, 1 tailed t-test of trial averages)
* *** * *
SCA Trial (Case Study, Milan TN, 2015)Mid-Canopy Leaves
Days After Treatment
One application made during early flowering
SCA Trial (Case Study, Milan TN, 2015)Flag Leaves
Days After Treatment
One application made during early flowering
SCA at Trial Milan (2015)
SCA Trial at Milan, YieldSingle Application (2015)
All treatments sprayed with Besiege at 7 oz/acre during early bloom
Threshold was reached at about the time of head emergence
Conclusions Sivanto provided the best control of SCA Transform and Centric were similar and next best There was not a large rate response with Transform (1 vs. 1.5 oz) or Sivanto (4 vs. 7 oz)
Lorsban, Dimethoate, and Pyrethroids were so-so, bad, and worse, respectively
Some candidates showed promise, at least at high rates◦ E.g. Strafer and Carbine
An obvious insecticide strategy would be to start with an application of Sivanto at 4 oz/acre and follow with a different MOA as needed (e.g., Transform)
Being “OK” Doesn’t Always Cut It
Questions?