The increased use of glyphosate and dicamba tolerant soybean can result in off-target
exposure and damages to seed potato tubers. For certified seed potato growers, this would affect
yields in the current season as well as plant emergence the following growing season. The
objective of this study was to determine the effects of ‘Atlantic’ and ‘Dakota Pearl’ potato
(Solanum tuberosum L.) tubers, used for seed from mother plants that were exposed to
glyphosate at 40 and 197 g ae ha-1, dicamba at 20 to 99 g ae ha-1, or the combination of
glyphosate and dicamba the previous year at the tuber initiation stage. At 8 weeks after planting
(WAP), daughter tubers from mother plants receiving glyphosate at 197 g ha-1, or the
combination of glyphosate and dicamba, had reduced emergence by 17 and 24% when compared
to the non-treated respectively. Furthermore, at 7 WAP, daughter tubers from mother plants
receiving the combination of dicamba at 99 g ha-1 and glyphosate at 197 g ha-1 or glyphosate at
197 g ha-1 had reduced plant height by 16 and 20%, respectively, compared to the non-treated.
Daughter plants from the mother plants that received the combination of glyphosate at 197 g ha-1
and dicamba at 99 g ha-1 had a 21% total yield reduction and canopy reduction when compared to
the non-treated. Results from the two field trials suggest that the combination of glyphosate at
197 g ha-1 and dicamba at 99 g ha-1, carried over from mother plants to daughter tubers for both
cultivars, the following growing season, to affect total yield from the daughter plant injury.
Further research needs to evaluate the influence of environmental stresses on the potato response
to sublethal amounts of glyphosate and/or dicamba.