Insect control in corn

Corn earworm, Helicoverpa zea, is a ubiquitous corn pest in the South. Kernel damage by corn earworm also is associated with increased levels of damage by other insects such as sap beetles and by infections of various types of molds. Major seed companies have a new transgenic Bt trait marketed as VT Triple PRO or Genuity VT Double PRO, which will be widely available in 2013 to control corn insect pests. Another Bt trait will be marketed as Agrisure Viptera. These new traits are reported to provide control of corn earworm and prevent kernel damage. UGA entomologists conducted a series of trials from 2010 to 2012 to assess the efficacy of a new Bt trait (Cry2A) within Genuity VT Triple PRO and VT Double PRO and a new Bt trait (Vip3A) within Agrisure Viptera. They compared corn hybrids with the new Bt traits, with an older single Bt trait, and without the new trait. Corn earworm infestation and kernel damage were measured and compared with similar hybrids without the new trait.The both new Bt traits reduced infestation by corn earworm and prevented kernel damage in corn ears. Agrisure Viptera containing the Vip3A gene virtually eliminated corn earworm infestation and kernel damage in corn ears. The benefits of these new Bt traits were most evident in later plantings of corn when risk of insect infestation is greatest. This new Bt traits will provide a valuable tool for preventing ear infestation and kernel damage by corn earworm. The control will prevent yield loss, but also will improve corn grain quality by avoiding secondary insect damage and fungal infection often associated with ear damage by corn earworm.