Efficacy of Neonicotinoid Seed Treatments Against Sugarcane Aphid in Grain Sorghum, 2014 *

An insecticide efficacy trial of neonicotinoid seed treatments against sugarcane aphids in grain sorghum was conducted at the Macon Ridge Research Station (MRRS) in Franklin Parish near Winnsboro, LA, in 2014. Grain sorghum was planted on 2 Jul and emerged on 6 Jul in a Gigger fine silty loam soil with minimum tillage. The test was an RCB design with four replications. Individual plots were four rows (centered on 40 inches) by 40 ft. Seed were treated with insecticide by mixing 2 pounds of seed with a 50:50 insecticide: water slurry until the seeds were completely coated and dry. At 19 DAP (days after planting) and 26 DAP, plots were sampled by randomly counting the number of SCA on 10 plants. At 33 DAP and 40 DAP, plots were sampled by counting the number of SCA on five random leaves. At 89 DAP, 10 heads per plot were rated for maturity by giving the heads a maturity rating of 1 (milk), 2 (soft dough), or 3 (hard dough). Data were analyzed using ANOVA and means were separated using an F -protected LSD ( P  < 0.05).

At 19 DAP, there were no differences among treatments ( Table 1 ). However, at 26 DAP and 33 DAP, all treatments had significantly fewer SCA compared to the nontreated check plots but did not differ from one another. By 40 DAP, the SCA population has declined across all plots, and no significant differences were observed. At 89 DAP, Gaucho had a significantly higher maturity rating compared to Cruiser and the nontreated check plots but did not differ from Nipsit Inside or Poncho. Additionally, Nipsit Inside and Poncho did not differ from Cruiser but were significantly more mature than the nontreated check plots. No phytotoxicity was observed with any treatment during this test.

Author notes