Occurrence and control strategy of Spodoptera frugiperda (Lepidoptera: Noctuidae) on maize plants in fields in Dongyang, Zhejiang, Eastern China.
Aim: This study aims to clarify the occurrence and control methods of Spodoptera frugiperda on fresh-eating maize varieties in Zhejiang Province, eastern China. Methods: The population dynamics of S. frugiperda adults was monitored by light trap and sex pheromone trap in Dongyang, Zhejiang in 2019. The oviposition and damage characteristics of S. frugiperda larvae on maize plants were observed in field, and the damage differences of S. frugiperda to different waxy and sweet maize varieties were determined by field investigation. The highly effective insecticides for field application were screened by field test. Results: The results of light trap and sex pheromone trap showed that there were two peaks of S. frugiperda adults in Dongyang, Zhejiang, which happened in late June and mid-September, respectively, and the peak in September was significantly higher than that in June. The moth tended to lay eggs on the young maize plants, and 80% of the eggs were laid on the upperside of leaves of maize. The larval feeding showed a significant tendency toward tender tissues, damaging heart leaves and ears of maize. The damage rates of S. frugiperda to different maize varieties were quite different, being 0-28.41% to sweet corn, and 0-42.50% to waxy corn. Emamectin benzoate, lufenuron, spinetoram, methoxyfenozide, phlorfenapyr, profenofos, methomy, indoxacarb, Celastrus angulatus and Mamestra brassicae NPV(MbNPV) were screened out as the highly effective pesticides to control S. frugiperda in the filed test in Dongyang, Zhejiang in 2019, the larval population decreased by 87.61%-98.99% at 3 d post pesticide application, and the persistence period was about 7-10 d in the field. Conclusion: S. frugiperda not only injures leaves of maize plants, but also ears. The damage in autumn is significantly serious than that in spring. For the control of S. frugiperda on maize plants, the integrated control measures including chemical control, biocontrol and physical induction control methods should be adopted. The control strategies also need to pay attention to seedling conservation at the seeding stage and ear conservation at the later stage, and to appropriately relax the control threshold from the jointing stage to the tassel stage.