Effects of Mepiquat Chrloride on Natural Plant Resistance to Tobacco Budworm in Cotton1

Abstract

The effects of mepiquat chloride (1,1‐dimethyl‐piperidinium chloride) (Pix®) on natural plant resistance to the tobacco budworm (TBW), (Heliothis rirescens F.) in cotton (Gossypium hirsutum L.) was studied in 1984 and 1985. A split plot randomized complete block experimental design with six replications was used. ‘Stoneville 213’ was grown in two row plots (2 ✕ 13.7 m) in a two‐planted oneskip row pattern on a Marietta sandy loam (fine‐loamy, siliceous, thermic Fluvaquentic Eutrochrepts) soil at Mississippi State, MS. Main plot treatments were with and without TBW and subplot treatments were three levels of mepiquat chloride (0, 50, and 100 g a.i. ha−1). The 100 g a.i. ha−1 level was split into 50 g at the recommended time of application and 50‐g 14 days later. Mepiquat chloride treatments caused significant yield increases at first harvest, but not in total yield, suggesting the typical induced earliness with this plant growth regulator. In the presence of an artificial infestation of TBW, no significant differences in yield were recorded either year among mepiquat chloride levels, indicating no increased plant resistance to artificial infestations of TBW.