Sorghum – Sugarcane Aphid Research Exchange Meeting Impact of insecticide seed treatments, tolerant sorghum varieties, and planting date on population growth of sugarcane aphid and sorghum yield in the Texas Panhandle Ada Szczepaniec Texas A&M AgriLife Sorghum – Sugarcane Aphid Research Exchange Meeting Dallas, TX, January 3 – 4, 2017

Introduction SCA in High Plains: timing of colonization, effectiveness of thresholds established in the South The goal of this research was to establish how planting date, insecticide seed treatments, and sorghum varieties affected colonization and population growth of sugarcane aphid (SCA) and sorghum yield.

Materials & Methods Replicated plots (8 rows by 50’) in Bushland, TX– each treatment was replicated four times for early and common planted sorghum Plots were scouted for aphids twice each week; once aphids colonized sorghum their density per leaf was established Insecticide (Sivanto® at 4 oz/A) was applied once densities reached the 50-125 aphids per leaf threshold Sorghum were harvested from a portion of each plot to estimate yield

SCA Densities in Early Planted Sorghum (Treated) 50-125 SCA/leaf

SCA Densities in Sorghum (Treated) Tolerant variety with insecticide seed treatment had the fewest SCA. Effective suppression was achieved when insecticide applied at 50-125 SCA/leaf.

No significant differences in yield between varieties regardless of seed treatment in early-planted sorghum

In absence of foliar insecticide treatments tolerant variety yielded better than susceptible

Tolerant variety had higher yield than susceptible var.

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Key Learnings Planting date affects SCA densities post-insecticide treatments, yield Seed treatments had an impact on SCA and on yield when sorghum planted at common planting date Tolerant variety had significant effect on SCA densities and yield Using threshold of 50-125 SCA/leaf allowed for successful suppression of aphids

Next Steps Repeat experiments in 2017 Expand number of tolerant variants Evaluate economic threshold of SCA (post-bloom sorghum)