Comparative Tolerance Levels of Maize Landraces and a Hybrid to Natural Infestation of Fall Armyworm

Abstract

Insect pests such as Spodoptera frugiperda cause significant losses to maize (Zea mays mays). Control of S. frugiperda is difficult, but the use of insect resistant cultivars, including tolerant cultivars, is a promising alternative, and landraces are a potential source of insect resistance. This study investigated tolerance to S. frugiperda in five Brazilian landraces, Amarelão, Aztequinha, Branco Antigo, Palha Roxa, and São Pedro, in relation to one conventional (non-Bt) hybrid, BM207, under field conditions. We assessed tolerance as the ratio of insecticide-free to insecticide-protected plants for plant height, stem diameter, and leaf chlorophyll content at two plant stages. Tolerance ratios varied across the maize genotypes, but inconsistently across plant variables, and cluster analysis revealed three groups based on tolerance ratios. A first group contained genotypes similarly tolerant to S. frugiperda, BM207, Palha Roxa, São Pedro, and Aztequinha, while the second and third groups each contained single genotypes, Amarelão, and Branco Antigo, which were considered not tolerant. Overall, the landraces Palha Roxa, São Pedro, and Aztequinha compared favorably to BM207 in terms of tolerance, and therefore may be valuable for management of this pest, and as germplasm sources to improve tolerance in other cultivars.

What is the potential of sugarcane borer in reducing sorghum fitness and grain production?

“…neither in its oviposition and feeding behaviour nor in its biology, being a characteristic that makes the plant better withstand from pest attack (Mitchell et al., 2016; Stout, 2013). Tolerance is expressed when the plant recovers, grows, and produces well when attacked by insect pests because of compensation and overcompensation mechanisms in vegetative and/or reproductive plant stages (Erb, 2018; Lima et al., 2022; Peterson et al., 2017; Sperotto et al., 2018). The largest body of research on plant tolerance is with aphids on maize, rice, rye, sorghum, and wheat (Smith, 2005), interestinly, all monocotyledonous plants species.…”

“…Tolerant genotypes also have the advantage of elevating the economic injury levels (EIL) for pest control by presenting lower yield losses to attack, benefiting reduction in the number of insecticide applications, extending the time of first control intervention, and pushing lower selection pressure on the pest populations to evolve resistance (Koch et al., 2019; Lima et al., 2022; Peterson et al., 2017). According to Wilson et al.…”

“…Tolerant genotypes also have the advantage of elevating the economic injury levels (EIL) for pest control by presenting lower yield losses to attack, benefiting reduction in the number of insecticide applications, extending the time of first control intervention, and pushing lower selection pressure on the pest populations to evolve resistance (Koch et al, 2019;Lima et al, 2022;Peterson et al, 2017). According to Wilson et al (2022), chlorantraniliprole had an 8-week residual effect of protecting sugarcane against SCB; taking into account that hybrid BRS has earlier crop cycle, with shorter flowering and maturation time, this may also be a factor that helps reduce the pest attack by allowing the plants to reach the grain-filling phase more quickly (Embrapa, 2016).…”

Side effects of insecticides used in soybean and corn for the egg parasitoid Telenomus remus (Hymenoptera: Scelionidae)

“…In this context, integrated pest management (IPM) programs for S. frugiperda have sought to combine different control methods for this noctuid pest and reduce production costs, as well as mitigate negative impacts on the environment and bene cial organisms (Lima et al 2022, Rosetti et al 2023). Thus, the preservation of biological control is crucial for sustainable S. frugiperda management, not only of massreleased natural enemies, but also of organisms naturally found in agroecosystems (Torres and .…”

Maize OPR2 and LOX10 Mediate Defense against Fall Armyworm and Western Corn Rootworm by Tissue-Specific Regulation of Jasmonic Acid and Ketol Metabolism

“…Maize production is constantly threatened by abiotic and biotic stressors, including the attack of insect herbivores [ 2 ]. Fall armyworm (FAW, Spodoptera frugiperda ) and western corn rootworm (WCR, Diabrotica virgifera virgifera ) are among the world’s most important maize pests [ 3 , 4 , 5 , 6 , 7 ].…”