The alfalfa weevil (Hypera postica) is an important pest that causes significant damages to alfalfa crops, reducing yield and quality, but there’s a solution. This research had two main goals to evaluate the efficacy of insecticides available in Korea for alfalfa weevil control and to provide data for pest management studies. The experiment, conducted from 2023 to 2024 at the National Institute of Animal Science in Cheonan, Republic of Korea, included four treatment plots: control (CON), early-occurrence (EAR), mid-occurrence (MID), and late-occurrence (LAT). It also included two frequency plots with primary and secondary insecticide using 50% fenitrothion emulsion, which made it truly comprehensive study. The primary insecticide was applied at the first observation of the alfalfa weevil larvae, with subsequent secondary applications at specified intervals. The results showed that two-times insecticide applications significantly reduced larvae populations and increased yield and nutrient content compared to a single application. Specifically, control rates ranged from 94 to 94.7% on the third day after treatment and from 72.2 to 93.4% on the seventh day. Plots with two applications had higher yields and crude protein content. The study concluded that the timing and frequency of insecticide applications are critical to maximizing alfalfa yield and quality, emphasizing the importance of optimized application strategies for effective pest control.

Ⅰ. INTRODUCTION
Ⅱ. MATERIALS AND METHODS
    1. Experimental design
    2. Insecticide control
    3. Forage yield and feed value
    4. Statistical analysis
Ⅲ. RESULTS AND DISCUSSION
    1. Insecticide effect
    2. Forage yield
    3. Chemical composition
Ⅳ. CONCLUSIONS
Ⅴ. ACKNOWLEDGEMENTS
Ⅵ. REFERENCES

• Seung Min Jeong(Grassland & Forages Division, National Institute of Animal Science, Cheonan 31000, Republic of Korea)
• Ki Won Lee(Grassland & Forages Division, National Institute of Animal Science, Cheonan 31000, Republic of Korea)
• Hyung Soo Park(Grassland & Forages Division, National Institute of Animal Science, Cheonan 31000, Republic of Korea) Corresponding author