Low Doses of Fenoxaprop-P-Ethyl Cause Hormesis in Littleseed Canarygrass and Wild Oat

Abstract

Hormetic effects of herbicides at ultra-low doses have been proved against range of crop species, although available data of herbicides hormesis about the weeds growth is very limited. This study investigates the promotive effect of low doses of fenoxaprop-Pethyl on growth and seed production of littleseed canarygrass and wild oat. Pot experiments were conducted twice in Wire House at Agronomic Research Area, University of Agriculture, Faisalabad, during 2014-15. Seven different concentrations of fenoxaprop-P-ethyl [0, 1, 3, 6, 9, 12 and 15 g a.i. ha-1] were applied as post emergence herbicide at 3-4 leaves stage of the weeds. Results revealed that increase in growth occurred within first two weeks after spraying at fenoxaprop-P-ethyl doses 1, 3 and 6 g a.i. ha-1. More growth stimulation as compared to all other treatments was observed at fenoxaprop-P-ethyl dose 6 g a.i. ha-1. This initial increase in growth sustains with time up to the maturity of both weeds and positively influences seeds production ability. Up to 28% and 17% increase in number of seeds per plants were occurred in littleseed canarygrass and wild oat, respectively. Doses above 6 g a.i. ha-1 negatively affect the weeds growth and seed production ability.

Herbicide hormesis can act as a driver of resistance evolution in weeds – PSII‐target site resistance in Chenopodium album L. as a case study

“…A similar correspondence between biomass gain and seed yield increase was reported for glyphosate hormesis with Cicer arietinum L. 15 and with several sensitive broadleaf winter weeds, 17 and for ACCase inhibitor hormesis with sensitive weeds. 16 Based on this, the observed hormesis in reproductive fitness may be just a secondary effect of the initial boost in vegetative fitness. However, direct hormetic responses in reproductive traits that are not associated with increased vegetative fitness are also indicated.…”

“…5,13 It is, however, unclear whether the observed early growth stimulation in R plants is also expressed as increased reproductive fitness and if this can occur under a regular herbicide application. Previous studies with S plants have shown expression of herbicide hormesis at the reproductive stage, [14][15][16][17] but not at practical field rates. Moreover, for glyphosate hormesis with conventional barley, an early biomass boost of up to 36% over control plants vanished during the 7 weeks after application and was not followed by enhanced seed yield.…”

Does the root to shoot ratio show a hormetic response to stress? An ecological and environmental perspective

“…and wild oat (Avena fatua L.) after spraying with the herbicide fenoxaprop-P-ethyl ( Fig. 6a) (Abbas et al 2016), and in tall fescue (Festuca arundinacea Schreb. ), ryegrass and other grass species (Vulpia sp.)…”

Does selective hormesis impact herbicide resistance evolution in weeds? ACCase‐resistant populations of Alopecurus myosuroides Huds. as a case study

“…The selective hormesis hypothesis was studied for field‐evolved populations of A. myosuroides showing problems associated with control by ACCase inhibitors as a consequence of the occurrence of ACCase TSR. ACCase inhibitors were selected because they have been shown to induce hormesis in weeds such as A. myosuroides , Avena fatua L. or Phalaris minor Retz., and are known for their propensity to select for resistance . Alopecurus myosuroides is strongly affected by ACCase resistance in Europe and has been shown to express NTSR with aryloxyphenoxypropionate‐type ACCase inhibitors as well as TSR .…”