Residual and Systemic Efficacy of Chlorantraniliprole and Flubendiamide Against Corn Earworm (Lepidoptera: Noctuidae) in Soybean

Abstract

Experiments were conducted in Mississippi from 2013 to 2015 to determine the systemic and residual efficacy of chlorantraniliprole and flubendiamide against corn earworm, Helicoverpa zea (Boddie), in soybean. Both insecticides were applied at V4 and R3. Ten leaves that were present at the time of application and 10 newly emerged leaves that were not present at the time of application were collected to measure residual and systemic efficacy, respectively. Ten pods were removed from each plot at R5.5. For all assays, corn earworm larvae were placed on plant material. Chlorantraniliprole appeared to provide systemic control of H. zea, but was dependent on soybean growth stage at the time of application. In the V4 experiment, chlorantraniliprole resulted in greater mortality than the control on new leaves at 7 d after treatment, but not at 14 d. In the R3 experiment, chlorantraniliprole resulted in greater than 90% mortality on new leaves at all evaluation intervals. Mortality of H. zea on new leaves was <17% for flubendiamide and was not different than the control. Both insecticides resulted in significant mortality of H. zea on leaves that were present at the time of application for at least 31 d after application. Chlorantraniliprole resulted in greater mortality than flubendiamide at 24 and 31 d. Neither insecticide resulted in mortality of H. zea feeding on reproductive structures. These results suggest that chlorantraniliprole moves to new vegetative structures but not to reproductive structures of soybean, and that flubendiamide does not move systemically.

Translocation of chlorantraniliprole and cyantraniliprole applied to corn as seed treatment and foliar spraying to control Spodoptera frugiperda (Lepidoptera: Noctuidae)

“…Chlorantraniliprole proved to be absorbed and translocated upward in soybean plants only when applied to stems or sprayed throughout the plant [7]. This application in the leaves and petioles did not result in the mortality of larvae feeding on new leaves, confirming the hypothesis that chlorantraniliprole is translocated only via xylem [7]. However, our results showed that chlorantraniliprole and cyantraniliprole, when applied in foliar spraying, were not translocated from treated to new untreated leaves of corn plants.…”

“…Insecticides applied by foliar spraying were not detected on all leaves evaluated after spraying, meaning that the active ingredients are not mobile via phloem. Chlorantraniliprole proved to be absorbed and translocated upward in soybean plants only when applied to stems or sprayed throughout the plant [7]. This application in the leaves and petioles did not result in the mortality of larvae feeding on new leaves, confirming the hypothesis that chlorantraniliprole is translocated only via xylem [7].…”

“…Insecticides of the diamides chemical group are widely used to control pests in many commercial crops worldwide [7]. Diamides was labeled for use over 10 years ago (2008) [8] and are classified in the group 28 by the Insecticide Resistance Action Committee (IRAC), acting as modulators of ryanodine receptors [9].…”

Managing pyrethroid‐ and Bt‐resistant bollworm in southern U.S. cotton

“…A series of experiments conducted during 2017 in North Carolina demonstrated the potential for the revival of an egg‐based threshold for bollworm in two‐Bt‐toxin cotton using the insecticide chlorantraniliprole. This technique was pioneered in the Midsouth and took advantage of the fact that this insecticide was xylem mobile (Lahm et al, 2007), translaminar, could move to newly grown vegetative tissue after application, and provided relatively extended residual (Adams et al, 2016b). The North Carolina experiments were initiated using foliar chlorantraniliprole (Prevathon) applications when bollworm eggs were deposited in Bt cotton, but larvae were not present, and when bollworm eggs were present, along with some larvae, in non‐Bt cotton (despite Cry resistance, larvae still developed more slowly on Bt cotton during 2017).…”

“…In soybean, bollworm can currently be controlled using foliar insecticides. For example, a recent survey of bollworm populations across the southern U.S. found that they were very susceptible to diamide‐class insecticides (Adams et al, 2016a) and that these could be effective, if used properly, in soybean (Adams et al, 2016b). While pyrethroid‐resistant bollworm populations have been present since the 1990s, use of this class for bollworm in both cotton and soybeans was still widespread until the 2010s.…”