Tolerance of ‘Salam’ Seashore Paspalum (Paspalum vaginatum) to Postemergence Herbicides

Abstract

Field studies were conducted to assess the tolerance of seashore paspalum (‘Salam’) to postemergence (POST) herbicides in Florida in 2000 and 2001. POST applications of bentazon (2,200 g/ha), clopyralid (420 g/ha), dicamba (280 g/ha), halosulfuron (70 g/ha), imazaquin (420 g/ha), mecoprop + 2,4-D + dicamba (160 + 180 + 40 g/ha), metsulfuron (30 g/ha), and quinclorac (1,700 g/ha) resulted in ≤10% injury 7 and 15 d after treatment (DAT), indicating their safety for POST application. Clethodim (280 g/ha) and sethoxydim (310 g/ha) caused 67 and 46% injury, respectively, 15 DAT averaged across 2000 and 2001. Ethofumesate was inconsistent between years, causing 30 and 60% injury 7 and 15 DAT, respectively, in 2000, but only 5 and 13% 7 and 15 DAT, respectively, in 2001. Imazapic and trifloxysulfuron-sodium caused an average of 47% injury 7 DAT in 2000 and 45% injury 15 DAT in 2001. Clethodim, ethofumesate, imazapic, sethoxydim, and trifloxysulfuron-sodium can not be safely applied POST to Salam seashore paspalum; however, bentazon, clopyralid, dicamba, halosulfuron, imazaquin, mecoprop + 2,4-D + dicamba, metsulfuron, and quinclorac are safe.

Herbicide Tolerance on ‘Sea Spray’ Seashore Paspalum Seedlings

“…Among the postemergence herbicides, halosulfuron, clopyralid, and quinclorac were the least injurious in our study, which is consistent with previous reports on established seashore paspalum (11,12,27,30). Injury from applications of salt water was also minimal (< 16%) (Table 2) and consistent with data from the use of ocean water (55 dS/m) on established seashore paspalum (31).…”

“…Injury from applications of salt water was also minimal (< 16%) (Table 2) and consistent with data from the use of ocean water (55 dS/m) on established seashore paspalum (31). Common three‐way herbicide combinations (2,4‐D, MCPP, dicamba) were injurious (< 78% 6 WAA) to seedlings in our study, which is consistent with other reports documenting injury to seashore paspalum from these herbicide combinations (5,7,10,30). Injury from combination products was greater in 2007 than 2008 on seedling turf, and in general these products caused more injury on seedlings than reports on established turf (5,7,10,30).…”

“…Salt water, halosulfuron, clopyralid, carfentrazone, metsulfuron, and quinclorac had coverage similar to the untreated check on each measurement date in both years (Table 3). This is consistent with other reports that salt water, halosulfuron, clopyralid, metsulfuron, and quinclorac are safe to use on seashore paspalum (11,12,27,30,31). There are no previous reports of herbicide tolerance of carfentrazone on seashore paspalum seedlings, but carfentrazone is labeled for use in established seashore paspalum (1).…”

“…Injury to seashore paspalum seedlings from triclopyr was high, which is consistent with other reports on established seashore paspalum (7,10). Ethofumesate is known to injure established seashore paspalum similar to our findings with seedlings (14,30). Ethofumesate injury is not severe enough to kill established seashore paspalum and has been proposed as a control method for bermudagrass in seashore paspalum (14), but not recommended for use on seashore paspalum by others (30).…”

“…Although there are limited herbicides with any label recommendations for seashore paspalum, most of those herbicides are specified for use on established seashore paspalum (Table 1). On established ‘Salam’ seashore paspalum, the postemergence herbicides clopyralid, dicamba, halosulfuron, imazaquin, mecoprop + 2,4‐D + dicamba, metsulfuron, and quinclorac were found to cause little toxicity (30). Halosulfuron and quinclorac are also safe to use on other cultivars of established seashore paspalum (11).…”