K. Al-khatib et A. Tamhane, Dry pea (Pisum sativum L.) response to low rates of selected foliar- and soil-applied sulfonylurea and growth regulator herbicides, WEED TECH, 13(4), 1999, pp. 753-758
Field experiments on dry pea (Pisum sativum) were conducted at five locatio
ns across the United States in 1995 and 1996 to investigate the effects of
low rates of chlorsulfuron, thifensulfuron, and dicamba applied postemergen
ce and of chlorsulfuron, metsulfuron, and clopyralid applied preplant incor
porated in the soil on pea plants. Although chlorsulfuron, thifensulfuron,
and dicamba caused significant injury symptoms on pea plants, they had litt
le effect on yield. The lowest rates of foliar applications that caused obs
ervable symptoms were 0.035, 0.086, and 1.56 g ai/ha for chlorsulfuron, thi
fensulfuron, and dicamba, respectively, whereas chlorsulfuron, thifensulfur
on, and dicamba rates that reduced pea yield by 25% were 0.18, 1.36, and 25
g/ha, respectively. Clopyralid caused more injury symptoms than metsulfuro
n or chlorsulfuron with soil application. However, the lowest rates of chlo
rsulfuron, metsulfuron, and clopyralid that caused observable symptoms were
lower than the rates that reduced yield. This study showed that pea plants
can sustain some level of plant injury without a large reduction in yield.