Sorghum Aphid Management with Harvest Aids: Transform and Sivanto at 14 d PHI

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

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 SeiterUniversity of Arkansas

Jeff GoreMississippi 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 BowlingTexas A&M University Upper Leaf - F4,12= 0.86 P = 0.5160 Lower Leaf – F4,12 = 1.04 P = 0.4270

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.

Sorghum Aphid Management with Harvest Aids: Transform and Sivanto at 14 d PHI