Corn rootworm is an extremely destructive corn pest. Recent university research indicates that for every root node lost to feeding, farmers can expect a 15% yield loss.
Pioneer® brand Optimum® AcreMax®1 (AM1) and Optimum® AcreMax® Xtra (AMX) insect protection products with integrated refuge allow growers to reduce refuge requirements with a single product. These products deliver flexibility and convenience for insect refuge management based on the proven performance of the Herculex® RW trait for CRW protection.
On-farm strip trials were conducted at 95 Midwestern locations in 2013 to evaluate the efficacy and grain yield performance of AM1 and AMX products with and without the use of soil-applied insecticide. Trials were placed primarily in corn-on-corn fields in areas with a history of moderate to severe corn rootworm feeding. High CRW pressure (defined as >1.5 on the Iowa State 0-3 NIS) was observed in 12 locations. Corn rootworm feeding was very intense at several of these locations. 4 trials had CRW injury ratings between 2.0 and 2.5 (very high) in the unprotected check, and 3 had CRW injury greater than 2.5 (severe).
Performance of AM1 and AMX products was very consistent, even under intense CRW pressure (Figure 1). Average CRW injury was significantly reduced relative to the protected check at all levels of CRW pressure. The addition of a soil insecticide to AMX and AM1 products tended to result in a slight reduction in CRW feeding, although the effect was not statistically significant.
Figure 1. Corn rootworm injury (NIS scores) observed with AM1/AMX products,
AM1/AMX products + soil-applied insecticide and no CRW protection (check)
in 2013 on-farm trials.
Comparison of AM1/AMX products and non-CRW protected corn with an insecticide demonstrated the superior CRW protection provided by the Optimum® AcreMax® family of products (Table 1). The AM1/AMX products performed significantly better than the soil-applied insecticide, both in terms of CRW feeding and corn yield.
Table 1. Corn rootworm injury and corn yield of AM1/AMX products, non-CRW
corn with a soil-applied insecticide, and an unprotected check across 7
on-farm trials with high CRW pressure in 2013.
DuPont Pioneer research has also focused on above-ground insect management. In 2012, a study evaluated DuPont™ Prevathon® insecticide for control of corn earworm and other insect pests on refuge and Optimum® Intrasect® hybrids.
Results showed that DuPont Prevathon insecticide improved standability of the refuge hybrid to a level similar to an untreated Optimum Intrasect hybrid (Figure 2).
Figure 2. Refuge hybrid without (left) and with (right) an application of DuPont Prevathon insecticide in a trial near Wynne, Ark., in 2012.