Selectivity of Diphenyl Ether Herbicides between Tomato (Lycopersicon esculentum) and Eastern Black Nightshade (Solanum ptycanthum)

Abstract

A non-linear dose-response model was used to analyze the response of tomato (Lycopersicon esculentumMill.) and eastern black nightshade (Solanum ptycanthumDun. #3SOLPT) to acifluorfen {5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid}, fluoroglycofen {carboxymethyl 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoate}, fomesafen {5-[2-chloro-4-(trifluoromethyl)phenoxy]-N-(methylsulfonyl)-2-nitrobenzamide}, and lactofen {(±)-2-ethoxy-1-methyl-2-oxoethyl 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoate}. The relative potency of these herbicides to both species was lactofen > fluoroglycofen > fomesafen > acifluorfen. Tomato was significantly more resistant to acifluorfen, fluoroglycofen, and lactofen than was eastern black nightshade, but there was no significant difference between species in response to fomesafen. At the rate required to reduce tomato weight by 10%, eastern black nightshade weight was reduced 48, 32, 20, and 5% by acifluorfen, fluoroglycofen, lactofen, and fomesafen, respectively.