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.

This study was conducted to investigate the numerical measurements of chestnut weevil, Curculio sikkimensis, reared in the lab and outdoor field from 2003 to 2006. Numerical measurements were calculated for the sex ratios, fresh weight, body length and width, head width, proboscis length, and antennal length. The female adult was bigger than male in fresh weight, body length and width, head width, proboscis, and antennal length. The size of egg was showed 0.8±0.03mm (n=20). Larval instars was measured 98 mg in body weight, 10.65 and 3.99 mm in body length and width, 1.70 mm in head width. Pupal size was also measured as 7.01±0.65mm in female, 6.53±0.48mm in male. The larva of C. sikkimensis overwintered through 3 years and the size of body weight, body length, and body width were decreased.

This study was conducted to investigate the numerical measurements of chestnut weevil, Curculio sikkimensis, reared in the lab and outdoor field from 2003 to 2006. Numerical measurements were calculated for the sex ratios, fresh weight, body length and width, head width, proboscis length, and antennal length. The female adult was bigger than male in fresh weight, body length and width, head width, proboscis, and antennal length. The size of egg was showed 0.8±0.03mm (n=20). Larval instars was measured 98 mg in body weight, 10.65 and 3.99 mm in body length and width, 1.70 mm in head width. Pupal size was also measured as 7.01±0.65mm in female, 6.53±0.48mm in male. The larva of C. sikkimensis overwintered through 3 years and the size of body weight, body length, and body width were decreased.

This study was conducted to investigate the seasonal occurrence of chestnut weevil, Curculio sikkimensis. The chestnuts infected by the weevils were collected from Gongju, Buyeo, and Cheongyang in Chungnam Province, Republic of Korea. Investigation was focus on the escape period of chestnut weevil larvae from the fruits, invading time and vertical distribution in soil, survival rates of larvae during overwintering, emergence period, emergence rate, and sex ratio and longevity of adults. For precocious species, larvae escaped the chestnut from the mid-September to the early-October, middle species and slow species, were escaped from the late-September to the mid-October and from the early-October to the mid-November. After escaping from the chestnut fruits all of the larvae burrowed into the soil within 35 minutes. Overwintering larvae inhabited in the range of 0~48 ㎝ from the soil surface and highly distributed in the range of 18~36 ㎝. The 74.1% of wintering chamber were distributed within 18~36 ㎝ from the surface. Survival rates observed were 38.0% in 1st year, 16.0% in 2nd years, and 2% in 3rd years, respectively. Seasonal occurrence period of C. sikkimensis was from the early-Aug. to early-Oct. and the optimal occurrence period was the early and mid-Sept. Emergence rate decreased to 8.4% in 1st year, 3.6% in 2nd years, and 0.8% in 3rd years, respectively. Sex ratio was showed in the range of 0.51-0.55. It is female biased ratio. Longevity of adults was 9.9 days for female and 8.9 days for male.

초 록 본 연구는 바구미과(Curculionidae)의 노랑무늬솔바구미(Pissodes nitidus), 노랑점검바구미(Pissodes obscurus), 흰점박이바구미(Shirahoshizo insidiosus), 밤바구미(Curculio sikkimensis), 버들바구미(Cryptorhynchus lapathi) 그리고 거위벌레과(Attelabidae)의 거위벌레(Apderus jekeli), 단풍나무거위벌레(Byctiscus puberulus regalis), 투리거위벌레(Euops splendidus), 복숭아거위벌레(Rhynchites heros) 그리고 왕바구미과(Rhynchophoridae)의 왕바구미(Sipalinus gigas) 유충의 형태학적 특성을 관찰하였다.