Performance of Fall Armyworm Preimaginal Development on Cultivars of Tropical Grass Forages

Area of Science:

• Agricultural Entomology
• Crop Science
• Integrated Pest Management

Background:

• Spodoptera frugiperda (fall armyworm) is a significant polyphagous pest impacting forage and grain crops.
• Grass forage cultivation, including Brachiaria, Panicum, and Cynodon species, is expanding in Brazil's integrated cropping systems.
• Larval performance of S. frugiperda can vary significantly based on host plant species and cultivars.

Purpose of the Study:

• To evaluate the biological performance of Spodoptera frugiperda larvae on 14 different grass forage cultivars.
• To identify forage cultivars that support lower or higher fall armyworm performance.
• To provide data for informed management decisions in integrated cropping systems susceptible to S. frugiperda.

Main Methods:

• Larval performance bioassays were conducted using 14 forage cultivars from Brachiaria, Panicum, and Cynodon genera.
• Key performance indicators, including survival rates and performance indexes, were measured for S. frugiperda.
• Comparative analysis of insect performance across different forage cultivars was performed.

Main Results:

• Significant variation in S. frugiperda larval performance was observed among the tested forage cultivars.
• Lowest larval survival rates were recorded on Panicum maximum 'Massai' and 'Tamani' cultivars.
• Highest insect performance indexes were achieved on Brachiaria brizantha 'Paiaguás', 'Marandu', and 'Xaraés' cultivars, and Brachiaria ruziziensis.

Conclusions:

• Certain Brachiaria cultivars demonstrate higher suitability for Spodoptera frugiperda development.
• Panicum maximum cultivars, particularly 'Massai' and 'Tamani', exhibit resistance or poor suitability for fall armyworm.
• Results inform strategic selection of forage cultivars to mitigate fall armyworm impact in Brazilian integrated cropping systems.