Comment on “Soybean Aphid Population Dynamics, Soybean Yield Loss, and Development of Stage‐Specific Economic Injury Levels” by M. A. Catangui, E. A. Beckendorf, and W. E. Riedell, Agron. J. 101:1080–1092 (2009)

Incorporating natural enemy units into a dynamic action threshold for the soybean aphid,Aphis glycines(Homoptera: Aphididae)

“…The economic threshold (ET = 273 aphids plant −1 ) does not specify the dynamic influence of natural enemies in space and time on soybean aphid populations. Catangui et al developed a threshold with a dynamic EIL that took into account soybean growth stages and growing conditions and allowed input of the actual market value of soybean and control costs; however, it ignored the abundance of natural enemies and was criticized for being unrealistic to field conditions …”

“…Catangui et al 34 developed a threshold with a dynamic EIL that took into account soybean growth stages and growing conditions and allowed input of the actual market value of soybean and control costs; however, it ignored the abundance of natural enemies and was criticized for being unrealistic to field conditions. 37 Zhang and Swinton 35 were the first to incorporate both the effect of natural enemies on soybean aphid density and the non-target mortality effect of insecticides on natural enemy abundance in an ET. However, they did not account directly for the relative voracity of different natural enemies.…”

Biology and Economics of Recommendations for Insecticide-Based Management of Soybean Aphid

“…Attempts have been made to explicitly account for variability in some of these factors for soybean aphid management; however, such dynamic thresholds are currently not recommended for soybean aphid management in the north-central United States. Catangui et al (2009) developed EILs for soybean aphid on different soybean growth stages; however, the caged conditions under which their experiment was performed affected environment, biological control and aphid emigration, and limit the ability to implement their recommendations for soybean aphid management (O'Neal et al 2010). ETs accounting for natural enemy abundance have also been developed (Hallet et al 2014;Zhang and Swinton 2009;Zhang and Swinton 2012), but have not been adequately validated for implementation in the north-central United States.…”