PurposeTo determine the population dynamics and occurrence rules of Spodoptera frugiperda (J. E. Smith), screening the germplasm resources with insect resistance to help effectively control S. frugiperda.
MethodsA field systematic survey was regularly conducted on 30 maize varieties using a 5-point sampling method with fixed points and plants. The population number, damage location and age of S. frugiperda larvae were recorded, and the dynamics of the larval population, vertical distribution, spatial distribution, and the resistance of different maize varieties on S. frugiperda population were determined.
ResultsS. frugiperda was harmful to maize during the whole growth period. The population reached the highest level in tasseling stage, and gradually decreased with the maturing of the ear. The number of larvae in different maize varieties showed the same trend, but the number of larvae was different. The vertical distribution of larva population on maize was different at different growth stages. The upper heart leaf was harmed at trumpet stage, and the female ear and its bracts were harmed at tasseling stage and later stage. The population of S. frugiperda showed an aggregation distribution in the maize tasseling stage, which was caused by natural factors. The population of S. frugiperda showed a uniform distribution in other growth stages, forming a trend of aggregation-diffusion-aggregation in general. There was a difference of more than 3.5 times between the least damaged variety Ruibai No. 6 and the most damaged variety TR151.
ConclusionS. frugiperda can cause damage throughout the maize growth stage, and its occurrence peak is the tasseling stage in early August; the population number of S. frugiperda is significantly different among different maize varieties. The results of study are beneficial to the prediction and control of S. frugiperda population in Shilin County.
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