Metabolic Resistance in the Fall Armyworm: An Overview

Abstract

The Fall Armyworm (FAW), Spodoptera frugiperda (Smith, 1797) (Lepidoptera: Noctuidae), is one of the most important pests in the American continent and has recently become an invasive species in Africa. It’s main form of control is through the use of insecticides, however during the last 40 years, due to continuous spraying and high doses used along with FAW’s high adaptative capacity, developed resistance to different classes of chemical insecticides. One of the main mechanisms enabling resistance in the FAW is by detoxification enzymes or so-called metabolic resistance. P450s, Carboxylesterases and Glutathione-S-Transferases are the main families of enzymes believed to mediate the detoxification process. These enzymes in the FAW, although widely studied, have been difficult to generalize into patterns. This happens mainly because FAW populations can have high genetic variability within the species, as they have different biotypes meaning that they can be morphologically identical but physiologically different and consequently, enzymatic responses to toxic compounds can also differ. There are also differences due to the diversity of biomes in which S. frugiperda is found, which due to adaptations to different host plants and other abiotic factors, it’s hard to predict enzymatic responses in insecticide resistance. In this context we aimed to review the literature regarding these three main enzymes families involved in metabolic resistance in S. frugiperda, by cataloguing, analysing and summarizing these studies.

Observations on the Relationships between Endophytic Metarhizium robertsii, Spodoptera frugiperda (Lepidoptera: Noctuidae), and Maize

“…In our current study, M. robertsii-colonized leaf tissue may have had no effect on FAW relative growth rate because of larval resistance to maize defense toxins and proteins. FAW is a generalist herbivore capable of enzymatically detoxifying toxic compounds, such as benzoxazinoids, a defensive compound common in maize [59], and plant protease inhibitors [60][61][62][63]. Colonized maize tissue may also have had defensive metabolites that were ineffective against FAW owing to the deactivation of metabolites in their midguts via antimicrobial peptides and high alkalinity, and the rapid evacuation of harmful metabolites from their bodies [27,[64][65][66].…”

Self-limiting fall armyworm: a new approach in development for sustainable crop protection and resistance management

“…The fall armyworm, Spodoptera frugiperda , is a significant and widespread pest of maize, sorghum, rice, and other economically important crops [ 1 ], and is now a significant global threat to agricultural productivity and food security. This moth is native to parts of the New World, is widespread across both North and South America, and is one of the most serious pests of maize in the Americas [ 2 ]. The caterpillars feed on crop plants, resulting in yield reductions and management costs valued at an estimated US$1 billion annually in Brazil alone [ 3 – 6 ].…”

The role of Desmodium intortum, Brachiaria sp. and Phaseolus vulgaris in the management of fall armyworm Spodoptera frugiperda (J. E. Smith) in maize cropping systems in Africa

“…Furthermore, the nocturnal habits of adult moths and the cryptic and burrowing behaviour of larvae into the maize whorl renders control difficult 11 . In addition to that, FAW has developed resistance to many chemical insecticides 12,13 . Excessive use of chemical insecticides also raises health and environmental concerns.…”