ARBUSCULAR MYCORRHIZAL FUNGI INFLUENCE ON GROWTH OF CREOLE MAIZE AND LARVAL DEVELOPMENT OF Spodoptera frugiperda (Lepidoptera:Noctuidae)

Abstract

Background: The fall armyworm Spodoptera frugiperda is one of the main pests of maize in Mexico. Its control and management have been performed mainly with pesticides. One of the alternatives is to incorporate arbuscular mycorrhizal fungi (AMF) because of the benefits they provide to plants improving their growth and promoting their defense system against this pest. Objective: Evaluate the effect of AMF in creole maize growth in reducing leaf damage and development of Spodoptera frugiperda larvae. Methodology: In greenhouse conditions, creole maize plants were inoculated with 80 spores of Funneliformis mosseae, Rhizophagus intraradices and without AMF. Height and stem diameter were determined in mycorrhized plants at 15, 30, and 45 days after plant inoculation. After 45 days, plants were infested with three third-instar larvae of S. frugiperda and left to feed for 12 days; fresh weight and cephalic capsule width and size were measured. Once larvae were removed, leaf damage was determined in plants by means of a visual scale, leaf area and mycorrhizal colonization. Results: Root colonization of maize plants by AMF had a significant effect (Tukey’s p ≤ 0.05) in creole maize growth expressed in plant height at 30 days and at 45 days in stem diameter only in plants inoculated with F. mosseae (Tukey’s p ≤ 0.05). Leaf damage by the fall armyworm was similar between inoculated and uninoculated with AMF. Larvae that consumed plant leaves inoculated with R. intraradices showed greater fresh weight compared to those inoculated with F. mosseae. Moreover, width of the cephalic capsule and size were similar between larvae fed with plants inoculated with and without AMF. Implications: The results provide new perspectives and considerations to incorporate AMF in management of fall armyworm in creole maize. Conclusion: These results show that AMF partially promote plant growth of creole maize; leaf damage is similar between plants with and without AMF. Insect weight increased depending on AMF species, which influenced their development.

Keywords

• maize
• insect development
• arbuscular mycorrhizal fungi
• plant growth
• herbivory