Current state of herbicides in herbicide‐resistant crops

Abstract

Current herbicide and herbicide trait practices are changing in response to the rapid spread of glyphosate-resistant weeds. Growers urgently needed glyphosate when glyphosate-resistant crops became available because weeds were becoming widely resistant to most commonly used selective herbicides, making weed management too complex and time consuming for large farm operations. Glyphosate made weed management easy and efficient by controlling all emerged weeds at a wide range of application timings. However, the intensive use of glyphosate over wide areas and concomitant decline in the use of other herbicides led eventually to the widespread evolution of weeds resistant to glyphosate. Today, weeds that are resistant to glyphosate and other herbicide types are threatening current crop production practices. Unfortunately, all commercial herbicide modes of action are over 20 years old and have resistant weed problems. The severity of the problem has prompted the renewal of efforts to discover new weed management technologies. One technology will be a new generation of crops with resistance to glyphosate, glufosinate and other existing herbicide modes of action. Other technologies will include new chemical, biological, cultural and mechanical methods for weed management. From the onset of commercialization, growers must now preserve the utility of new technologies by integrating their use with other weed management technologies in diverse and sustainable systems.

Genetically modified crops in Switzerland: implications for agrosystem sustainability evidenced by multi-criteria model

“…Firstly, the amounts of subsidies (direct payments) were postulated as similar for GM crops as for conventional ones. Secondly, the appearance of weeds tolerant to HT plants (Brookes and Barfoot 2013;Green 2014), insect resistance for Bt species, apple scab, or fire blight resistances were not monitored here despite their reported occurrence (Vogt et al 2013;Fahrentrapp et al 2013;Jin et al 2015) but were nonetheless discussed. MCDA and more generally multiattribute models are not directly suitable for time-series evaluation (Bohanec et al 2008).…”

“…Resistances from target insects can be overcome (at least temporarily) by using stacking of various toxin variants (13 different Bt proteins have been approved in corn in the USA (Meissle et al 2011;Abbas et al 2013), use of natural refuges (Jin et al 2015), or increase of insecticide spraying. For HT systems, about 44 plant species from at least ten families are reported to be resistant to glyphosate (Green 2014). Resistance to fire blight in apple is thought to be a gene-to-gene relationship and therefore easily overcome by the parasite.…”

Germination test as a fast method to detect glyphosate-resistant sourgrass

“…In plants, resistance may be naturally occurring or induced by such techniques as genetic engineering or selection of variants produced by tissue culture or mutagenesis (Green, 2014). Therefore, according to Christoffoleti & Ovejero (2008), the weed resistance to an herbicide is characterized by the heritability of some biotypes, in a given population, to survive and reproduce after it is exposed to a lethal dose of the herbicide for normal individuals (susceptible) of that specie.…”

“…More recently, a considerable increase on glyphosate utilization occurred due to the large adoption of glyphosate-resistant crops by growers (Green, 2014).…”

“…The intensive use of glyphosate over wide areas has selected weed populations that are resistant to its mode of action (Moreira & Christoffoleti, 2008;Green, 2014). Due to the enormous relevance of glyphosate to modern agriculture, efforts must be directed in order to promote a rational use of this herbicide (Soares et al, 2012).…”