Exudation of Mesotrione from Potato Roots Injures Neighboring Plants

Abstract

Mesotrione is an effective herbicide for volunteer potato control but is not selective in several crops, including onion and carrot. Studies were conducted in 2006 to evaluate the effectiveness of wiper-applied mesotrione for control of volunteer potato in a potato crop. Surprisingly, nontreated potatoes growing adjacent to mesotrione-treated plants exhibited bleaching symptoms resembling mesotrione injury. Additional field trials confirmed injury to nontreated plants growing within 26 cm of potatoes treated with mesotrione applied with a wiper at 0.25, 0.5, and 1% (v/v) solutions. Greenhouse bioassays confirmed that mesotrione applied to potato leaves moved down through the plant and was exuded into perlite potting medium in sufficient quantities to injure potato plants that were exposed to the leachate from the perlite pots. In tracer studies, 52% of 14C-labeled mesotrione applied to potato leaves was absorbed into the potato plant by 15 d and 15% of the absorbed 14C-mesotrione was exuded into the soil and soil leachate. Mesotrione applied to potato by the wick application method has potential to injure neighboring susceptible plants from root uptake of exuded mesotrione.

Evaluation of broadcast and spot herbicide applications for narrowleaf goldenrod [Euthamia graminifolia (L.) Nutt.] management in lowbush blueberry

“…Sequential mesotrione applications caused greater visual injury and density reductions than did single applications (Table 5), so reductions in rhizome growth during the year of application are plausible and should be measured in future research. Boydston and Al-Khatib (2008) also reported that up to 15% of foliar-applied mesotrione was translocated to developing roots and tubers of potato. Sequential mesotrione applications to goldenrods may therefore increase the amount of mesotrione translocated to roots and rhizomes, likely contributing to the increased control observed in the bearing year.…”

“…Glufosinate generally provides variable control of established perennial weeds (Bradley and Hagood 2002;Nelson et al 2002;Pline et al 2000) but does exhibit phloem mobility and translocation to roots in some weed species (Pline et al 1999;Steckel et al 1997) that may have contributed to additional rhizome injury when used as a spot application. Root translocation of mesotrione can also occur (Boydston and Al-Khatib 2008), suggesting this herbicide may have also caused damage to rhizomes. Reductions in bearing-year shoot density after spot applications also indicate spot applications of mesotrione are more effective than single broadcast applications (Tables 5 and 6), likely due to improved coverage of target plants with spot applications relative to broadcast applications.…”

Herbicides in unexpected places: non-target impacts from tree root exudation of aminopyralid and triclopyr following basal bark treatments of invasive chokecherry (Prunus padus) in Alaska

“…Among these, root exudates are well known to act as chemical defense mechanisms to protect border cells and respond to possible infections (Baetz and Martinola 2014). Herbicides, when applied to susceptible and non-susceptible plants, may alter or become a component of root exudates (Barker and Dayan 2019;Boydston and Al-Khatib 2008;Dinelli et al 2007;Hickman et al 1989;Kremer et al 2005). Studies of herbicide translocation of pyridine carboxylic acids have indicated that the distribution variability of herbicides to roots and other plant parts is wide, and the compounds are not metabolized within the plants (Bukun et al 2009;Lewis et al 2013).…”

“…Studies of herbicide translocation of pyridine carboxylic acids have indicated that the distribution variability of herbicides to roots and other plant parts is wide, and the compounds are not metabolized within the plants (Bukun et al 2009;Lewis et al 2013). When released from treated plants, root exudates may have the potential to cause non-target impacts to species that are sensitive to the applied herbicide (Boydston and Al-Khatib 2008;Dinelli et al 2007;Hickman et al 1989).…”

“…Previous field studies involving basal bark treatments of invasive figs (Ficus carica L.) with triclopyr identified soil residue concentrations indicative of high rates of application and suspected this was due to residues physically washing (dripping) down the trunk during subsequent precipitation events (Holmes and Berry 2009). Additional field and laboratory studies on the control of herbaceous weeds determined that herbicide leakage from roots results in impacts to surrounding vegetation (Boydston and Al-Khatib 2008;Hickman et al 1989).…”