Sorghum – Sugarcane Aphid Research Exchange Meeting Key Question #2: How can harvest aids be used in combination with the industry standards, Transform and Sivanto, when applied at a 14 d PHI? Robert Bowling Texas A&M University Sorghum – Sugarcane Aphid Research Exchange Meeting Dallas, TX January 3 – 4, 2017
Collaborators Name Affiliation Trial Location Plant Date Spray Nick Seiter University of Arkansas Monticello, AR 4/25/16 7/29/16 Jeff Gore Mississippi State University Stoneville, MS 5/12/16 9/18/16 Francis Reay-Jones Clemson University Florence, SC 5/25/2016 Robert Bowling Texas A&M University Corpus Christi, TX 3/15/16 7/21/16
Introduction Sugarcane aphid on sorghum leaves during application of harvest aids frequently move to sorghum head SCA activity on sorghum heads may result in honeydew accumulations and present harvest issues/grain loss/harvest delays Key question: How can harvest aids be used in combination with the industry standards, Transform and Sivanto, when applied at a 14 d PHI?)
Materials & Methods University research farms or grower fields Randomized complete block design or as replicated strips Data Collected Number SCA on upper and lower leaves Number of aphids/head Timing: 3, 7, 10, and 14 days after application Rate grain heads for presence and severity of honeydew Light: honeydew is present and easily visible in parts of the head, but no sooty mold and few cast skins Moderate: honeydew is present throughout the head, with cast skins and sooty mold in patches Heavy: all or most of the head is covered with honeydew, sooty mold, and cast skins Make observations on amount of grain lost (kernels on the ground) and collect data if appropriate.
Materials & Methods
Nick Seiter University of Arkansas
Nick Seiter University of Arkansas
Nick Seiter University of Arkansas
Nick Seiter University of Arkansas
Nick Seiter University of Arkansas
Jeff Gore Mississippi State University
Jeff Gore Mississippi State University
Jeff Gore Mississippi State University
Jeff Gore Mississippi State University
Key Learnings SCA is a frustrating research subject! Rapid movement by SCA following NaClO3 application/rapid plant desiccation? SCA did move to head when RU used as defoliant or no harvest aid applied Aphids were successfully controlled and movement to the head was minimized when insecticide applied (Sivanto or Transform)
Next Steps What is the threshold for sugarcane aphids at hard dough/maturity?
Discussion Written Management suggestions (possibly a short publication) needed to help sorghum producers manage late-season SCA on sorghum. Is there value in a Harvest Aid Management document? What information should be included (i.e. insecticide rates, SCA populations worthy of a late-season/harvest aid tank mix, PHI’s are obvious, other info)? Can this document be a single offering for all sorghum production regions or should it be region specific?
Discussion Is there value in a Harvest Aid Management document? What information should be included (i.e. insecticide rates, SCA populations worthy of a late-season/harvest aid tank mix, PHI’s are obvious, other info)? Can this document be a single offering for all sorghum production regions or should it be region specific?
Extra Slides Monticello, AR trial design Randomized complete block, 4 replicate blocks arranged in columns, plots 4 rows x 40 feet with 2 rows unsprayed border Variety AgVenture AV7R21 planted 25 April (90,000 seeds per acre, 38-inch row spacing) Treatments applied 15 August using self-propelled Mudmaster multi-boom sprayer 10 plants per plot with colonies of aphids on the flag leaves were marked with flagging tape prior to treatment Marked plants in plots were sampled 19 Aug., 22 Aug., 25 Aug, 29 Aug. Harvested 29 August
Robert Bowling Texas A&M University Upper Leaf - F4,12 = 0.86 P = 0.5160 Lower Leaf – F4,12 = 1.04 P = 0.4270
Robert Bowling Texas A&M University Upper Leaf - F4,12 = 1.75 P = 0.5160 Lower Leaf – F4,12 = 0.76 P = 0.5737
Robert Bowling Texas A&M University Upper Leaf - F4,12 = 0.62 P = 0.6589 Lower Leaf – F4,12 = 1.52 P = 0.2590
Extra Slides Corpus Christi, TX trial design Randomized complete block, 4 replicate blocks arranged in columns, plots 4 rows x 40 feet with center 2 rows sprayed Variety Pioneer 84P80 planted 10 March (55,000 seeds per acre, 30-inch row spacing) Treatments applied 24 August using hand-held CO2 sprayer TT 11015 nozzle tips 10 plants per plot with colonies of aphids on plants were marked with flagging tape prior to treatment Marked plants in plots were sampled 23 June, 27 June, and 1 July. Plot area was not harvested because aphids never moved to head.