Root histology of two turfgrass cultivars in response to selected herbicides

Foliage growth and root cellular responses of Penncross creeping bentgrass (Agrostis palustris Huds.) and Tifgreen bermudagrass [Cynodon dactylon (L.) Pers. x Cynodon transvaalensis Burtt- Davy] to selected herbicides were observed. Also noted was the ability of these cultivars to recover from herbicide induced root injury. The most severe herbicide damage in Penncross bentgrass resulted from metribuzin [4-amino-6-tert-buty1-3-(methylthio)-as-triazin- 5(4H)-one], napropamide [2-(a-naphthoxy)-N,N-diethylpropionamide], and prosulfalin [N-[[4-(dipropylamino)-3,5- dinitrophenyl]sulfonyl]-S,S-dimethylsulfilimine] treatments which killed all of the plants. Effects on bentgrass were less severe from ethofumesate [(±)-2-ethoxy-2,3-dihydro-3,3-dimethyl-5-benzofuranyl methanesulfonate] and NC-20484, and slight with oxadiazon [2-tert-butyl- 4(2,4-dichloro-5-isopropoxyphenyl)-δ²-1,3,4-oxadiazolin-5- one]. The most extensive damage to Tifgreen bermudagrass was from ethofumesate, metribuzin, napropamide, and prosulfalin. NC-20484 caused severe root cellular abnormalities, but no apparent foliar damage. Oxadiazon effects on bermudagrass were very slight.