Ear-feeding resistance offers new insights into host plant resistance to fall armyworm Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) in maize

Effect of Selected Maize (Zea mays L.) Genotypes on the Biology of the Fall Armyworm (Spodoptera Frugiperda JE Smith) Under Controlled Environment

Maize (Zea mays L) has lost its natural defence mechanisms against herbivorous pests due to domestication and artificial selection that focused on productivity rather than pest resistance. The fall armyworm (FAW) has become an invasive pest of maize and other crops in Africa.  The objective of this study was to determine the effect of maize genotypes, SC DUMA43, SC SUNGURA301, HARAKA WH101, Yellow landrace, Red landrace and FAWTH2003 on FAW feeding and development. The experiment was set in a laboratory in a no-choice bioassay in a Complete Randomised Design (CRD) replicated three times. Data was collected on the leaf weight after feeding, leaf damage score, larval mortality, average larvae weight, instar progression, larval period, pupation duration, average pupal weight, adult sex ratio and total lifecycle. Data was tested for normality and subjected to analysis of variance (ANOVA) using SAS v. 9.3.0.  Genotype SC Sungura 301 and Haraka WH 101 were more preferred by FAW with leaf portion losses of 2.83g and 2.86g respectively, compared to FAWTH2003 with leaf portion loss of 2.02g. Maize genotypes had a significant (p ≤ 0.001) effect on larval weight, mortality and development time. FAWTH2003 had the highest mortality of the larvae at p ≤ 0.0001 significance. The larvae that fed on HARAKA WH101 had the heaviest larval weight (0.15 g) with the shortest larval duration (16.33 ± 0.88 days), suggesting superior nutritional quality and high susceptibility to infestation. In contrast, those larvae that fed on the FAWTH2003 genotype had the lightest larval weight (0.10g) and the longest duration (19.67±1.20 days), suggesting cases of antibiosis and possible antixenosis effects that reduced growth and delayed development. The inverse relationship between larval weight and development duration highlights the role of maize genotype in influencing FAW growth dynamics, with resistant varieties prolonging development and suppressing larval biomass accumulation. Integrating host plant resistance (HPR) in FAW management is necessary as an Integrated Pest Management (IPM) strategy.

Host-mediated variation in insect biology, feeding efficiency and defensive phytochemicals underlying resistance of poplar clones to Clostera cupreata (Butler, 1881)

Integration of Selective Insecticides with Metarhizium anisopliae for Sustainable Management of Fall Armyworm, Spodoptera frugiperda (J.E. Smith) in Maize

Spodoptera frugiperda (J.E. Smith) is a destructive invasive pest that poses a serious threat to maize production, necessitating the development of sustainable management strategies. The present study evaluated the efficacy of integrating selective insecticides with Metarhizium anisopliae for the management of fall armyworm under field conditions. Field experiments were conducted at two locations in South Gujarat, India, during the Rabi 2025–26 season using novaluron 5.25 + emamectin benzoate 0.9 SC and thiamethoxam 12.60 + lambda-cyhalothrin 9.50 SC applied alone and in combination with M. anisopliae, along with M. anisopliae alone and an untreated control. Repeated-measures mixed-effects analysis revealed significant treatment effects on plant infestation, leaf damage, cob infestation and cob yield. Among the evaluated treatments, novaluron 5.25 + emamectin benzoate 0.9 SC integrated with M. anisopliae recorded the lowest plant infestation (32.92%), leaf damage score (2.70) and cob infestation (11.01%), and produced the highest cob yield (13.21 t ha⁻¹), representing a 40.53% increase over the untreated control. Although statistically comparable with novaluron 5.25 + emamectin benzoate 0.9 SC applied alone for most parameters, the integrated treatment consistently showed numerically superior performance. In contrast, M. anisopliae applied alone provided only moderate suppression of fall armyworm and lower yield protection than insecticide-based treatments. These findings demonstrate that integrating M. anisopliae with selective insecticides improves fall armyworm management and maize productivity, highlighting its potential as an effective component of integrated pest management (IPM) for sustainable maize production.

Adapting Microbial Inoculants, Plant Extracts, and Legume Intercrop to Mitigate Fall Armyworm (Spodoptera frugiperda) and Improve Maize (Zea mays L) Performance

Infestation by the invasive fall armyworm-FAW (Spodoptera frugiperda) pest has recently emerged as an important constraint for maize (Zea mays L) production, which is frequently managed using chemical pesticides. However, the inappropriate use of chemical pesticides can cause deleterious effects on the environment and humans, and enhance pest resistance. This study evaluated the potential of locally produced microbial inoculants and plant bioactive extracts, and push-pull strategy of cowpea (Vigna unguiculata) intercropping as control measures for FAW infestation on maize plants, while serving as nutrient replenishing source via biological nitrogen fixation. This field study was setup as split plot in two alternate cropping seasons (September 2021 and April 2022) and cropping systems (mono- and inter-cropping) as main plots, and seven treatments as sub-plots (Control, chemical–NPK+Lamida gold, Tithonia diversifolia–Ti+Piper guineense–Pi, Plant growth-promoting bacteria–PGPB+Endophytic fungi–EF, EF+Pi and PGPB+EF+Ti+Pi). Results highlight statistical identical performance of microbial inoculants or plant bioactive extracts and chemical pesticides in reducing FAW infestation by 13-73.9 %. Bio-amendments significantly (P<0.05) increased maize height, 1000 maize grain weight, cob length and degree of filling compared to the untreated control. Maize-cowpea intercrop significantly increased FAW infestation in some treatments when compared to maize monocrop. In September 2021, FAW infestation correlated (P<0.05) negatively with 1000 maize grain weight (r = -0.7), cob length (r = -0.7), number of grains on the longest line (r = -0.8) and degree of filling (r = -0.7) in the monocrop plot. These findings highlight the ability of locally produced microbial inoculants and plant bioactive extracts as sustainable alternatives to mitigate FAW infestation on maize. Thereby, opening up possibilities for further investigation on mechanisms of action that can be explored for biological pest control.

Molecular Characterization and Endophytic Colonization of a Native Beauveria bassiana Isolate in Maize: Effects on Plant Growth and Spodoptera frugiperda Herbivory

Simple Summary Beauveria bassiana is a beneficial fungus widely known for its ability to infect and kill insect pests. In addition to this role, it can live inside plant tissues as an endophyte, helping plants grow and increasing their resistance to pests. In this study, we characterized a Mexican isolate of B. bassiana (Bb-IIAF1-24) using molecular techniques and evaluated its ability to colonize maize plants. Phylogenetic analyses confirmed that the isolate belongs to B. bassiana and is closely related to isolates from other regions of the world. We then inoculated maize plants through either foliar spraying or soil application and assessed fungal colonization, plant growth, and damage caused by the fall armyworm, Spodoptera frugiperda, a major maize pest. The fungus successfully colonized roots, stems, and leaves, with the highest colonization levels observed in leaves. Soil application increased stem diameter, while foliar application promoted greater plant height. Both inoculation methods reduced leaf damage caused by the insect compared with untreated plants. These findings demonstrate that the Mexican isolate Bb-IIAF1-24 can establish as an endophyte in maize and provide benefits related to plant growth and protection against insect herbivory, highlighting its potential for sustainable crop management.

Complementary effects of silicon-induced plant defense and Trichogramma pretiosum biological control of fall armyworm in maize