Enhancing Integrated Pest Management in GM Cotton Systems Using Host Plant Resistance

Abstract

Cotton has lost many ancestral defensive traits against key invertebrate pests. This is suggested by the levels of resistance to some pests found in wild cotton genotypes as well as in cultivated landraces and is a result of domestication and a long history of targeted breeding for yield and fiber quality, along with the capacity to control pests with pesticides. Genetic modification (GM) allowed integration of toxins from a bacteria into cotton to control key Lepidopteran pests. Since the mid-1990s, use of GM cotton cultivars has greatly reduced the amount of pesticides used in many cotton systems. However, pests not controlled by the GM traits have usually emerged as problems, especially the sucking bug complex. Control of this complex with pesticides often causes a reduction in beneficial invertebrate populations, allowing other secondary pests to increase rapidly and require control. Control of both sucking bug complex and secondary pests is problematic due to the cost of pesticides and/or high risk of selecting for pesticide resistance. Deployment of host plant resistance (HPR) provides an opportunity to manage these issues in GM cotton systems. Cotton cultivars resistant to the sucking bug complex and/or secondary pests would require fewer pesticide applications, reducing costs and risks to beneficial invertebrate populations and pesticide resistance. Incorporation of HPR traits into elite cotton cultivars with high yield and fiber quality offers the potential to further reduce pesticide use and increase the durability of pest management in GM cotton systems. We review the challenges that the identification and use of HPR against invertebrate pests brings to cotton breeding. We explore sources of resistance to the sucking bug complex and secondary pests, the mechanisms that control them and the approaches to incorporate these defense traits to commercial cultivars.

Laccase GhLac1 Modulates Broad-Spectrum Biotic Stress Tolerance via Manipulating Phenylpropanoid Pathway and Jasmonic Acid Synthesis

“…Cotton bollworm (Helicoverpa armigera), once thought to be the most serious insect pest of cotton, has been well controlled by the widely planted Bt cotton (Wu et al, 2008). However, some new challenges have emerged: continuously planted mono-Bt cotton can lead to pest resistance; and in fields planted with Bt cotton, the decreased spraying of pesticides may result in non-Bt-targeted pests becoming new key pests, particularly piercing-sucking insects (Wu et al, 2008;Trapero et al, 2016).…”

Sources of plant resistance to thrips: a potential core component in cotton IPM

“…Balakrishnan (2006) reported that constitutive allelochemical components, such as gossypol or condensed tannin, showed a negative significant relationship with thrips population development. It is likely that domestication and selection for yield and fibre quality traits along with desirable agronomic traits in cotton has resulted in limited genetic diversity in elite commercial cotton varieties (Trapero et al, 2016). Further, the availability of insecticides, and now GM-cotton with pest resistance, reduces the need for plant defences against pests.…”

“…We also included another tetraploid cotton species, G. barbadense, in which resistance has been reported against thrips (Zhang et al, 2013). We Resistance to other pests (e.g., mites, whiteflies) Miyazaki et al (2012Miyazaki et al ( , 2013a included the diploid species G. arboreum, G. thurberi, and G. trilobum, as they have been reported to have resistance against other cotton pests (Trapero et al, 2016). We assessed plant resistance over four cotton seasons, from 2010 to 2014, in the field by counting the thrips and measuring the amount of leaf damage and the plant dry weight for each genotype.…”

Plant training for induced defense against insect pests: a promising tool for integrated pest management in cotton

“…Enhancing cotton pest management using plant natural defenses has been described as a promising way to improve the management of insect pests . Induction of plant defenses is one of the pathways that is currently being explored .…”