Cabbage is one of the major vegetable crops especially in Korea. Various insect pests intimidate the cabbage production. Moreover, an excessive spray of chemical insecticides leads to development of insecticide resistance as well adverse effects on environment and humans. The brassica leaf beetle, Phaedon brassicae, is a coleopteran pest. Both larval and adult stages feed cabbage. This study aimed to develop an effective microbial biopesticide against P. brassicae by adding immunosuppressive agent to Bacillus thurigiensis (Bt). To determine an optimal immunosuppressive agent, two bacterial species of Photorhabdus temperata subsp. temperata (Ptt) and Xenorhabdus nematophila were compared in their insecticidal activity against P. brassicae, and Ptt was selected. Among four subspecies of Bt, B. thuringiensis subsp. tenebrionis (Btt) was selected. Ptt bacterial culture broth possessed immunosuppressive agent(s) because the bacterial culture broth significantly increased other bacterial growth in P. brassicae hemolymph. When the Ptt broth was added to Btt, it significantly increased the insecticidal activity of Btt. Bt-Plus was prepared by mixing Btt and Ptt bacterial culture and sprayed the cabbage infested by P. brassicae. The Bt-Plus was much more effective than Btt treatment. This study reports a novel Bt insecticide to control P. brassicae.

The leaf beetle, Chrysolina aurichalcea (Coleoptera: Chysomelidae), is a pest damaging plants of Compositae. In order to understand the genetic diversity and geographic variation we sequenced a portion of mitochondrial COI gene (658 bp) and complete nuclear internal transcribed spacer 2 (ITS2) of the species collected from seven Korean localities. A total of 17 haplotypes (CACOI01 ~ CACOI17), with the maximum sequence divergence of 3.04% (20 bp) were obtained from COI gene sequence, whereas 16 sequence types (ITS2CA01 ~ ITS2CA16), with the maximum sequence divergence of 2.013% (9 bp) were obtained from ITS2, indicating substantially larger sequence divergence in COI gene sequence. Phylogenetically, the COI gene provided two haplotype groups with a high nodal support (≥ 87%), whereas ITS2 provided one sequence type group with a high nodal support (≥ 92%). The result of COI gene may suggest the presence of historical biogeographic barriers that bolster genetic subdivision in the species. Different grouping pattern between COI gene and ITS2 sequences were interpreted in terms of recent dispersal, reflected in the ITS2 sequence. Finally, finding of unique haplotypes and sequence types only from Beakryeng-Islet population was interpreted as an intact remnant of ancient polymorphism. As more samples are analyzed using further hyper-variable marker, further fruitful inference on the geographic contour of the species might be available.

The leaf beetle, Chrysolina aurichalcea (Coleoptera: Chysomelidae), is a pest damaging plants of Compositae. In order to understand the genetic diversity and geographic variation of the species we sequenced a portion of mitochondrial COI gene (658 bp) and complete nuclear internal transcribed spacer 2 (ITS2) collected from seven Korean localities. A total of 18 haplotypes (BARCA01 ~ BARCA18), with the maximum sequence divergence of 3.04% (20 bp) were obtained from COI gene sequence, whereas 17 sequence types (ITS2CA01 ~ ITS2CA17), with the maximum sequence divergence of 2.013% (9 bp) were obtained from ITS2, indicating substantially larger sequence divergence in mitochondrial gene sequence. Phylogenetically, the mitochondrial DNA has shown several haplotypes formed independent groups with substantially high node support (≥ 90%), whereas no such grouping was evidenced for ITS2, indicating different behaviors of the two molecules. Such difference may reflect a diverse dynamics of the species such as biogeographic history, mating behaviors, and also possibly different mode of inheritance of the two molecules, but requires further scrutinized examination of the dataset. In terms of population genetic perspective, overall no population subdivision was detected from both molecules, except for locality 7 (Eocheong islet) from mitochondrial DNA. As more scrutinized analysis is performed, further fruitful inference on the geographic contour of the species might be available.

Gregarine parasite (Apicomplexa: Protozoa) was observed in the population of daikon leaf beetle, Phaedon brassicae Baly (Coleoptera: Chrysomelidae) in Daegwallyeong. Morphological features of the gregarine in gut of P. brassicae have been studied by light microscope and scanning electron microscope with particular attention to the relationship between the epimerite and the host epithelium. On the average of mature trophozoite length and width are 100 and 40㎛, respectively. Based on 1.727kb of 18S rDNA sequence, this gregarine grouped in eugregarine.

본연구는 오리나무잎벌레(Agelastica coerulea Baly)성충의 유면 유기에 미치는 온도와 광주기 영향 및 유약호르몬(juvenile hormome III)과 탈피호르몬(20-hydroxyecdysone)이 휴면중인 성충에 미치는 영향을 조사하기 위하여 수행되었다. 오리나무잎벌레는 일년에 일회 발생하며 난, 유충, 용 성충기간은 가각 7~10일, 19~21일, 14~15일, 약 10개월로 조사되었다. 오리나무잎벌레의 알과 유충을 와 의 조건에서 광주기를 각각 16L/8L, 12L/12D, 8L/16D로 달？여 사육하여도 모든 성충이 휴면에 들어가 이들은 필수성충휴면을 하는 것으로 생각되었다. 휴면기간동안 난소는 거의 발육되지 않았으며 유면말기의 개체를 , 16L/8D에 노출시키면, 난소소관이 급속하게 발달되었다. 휴면중인 성충에 유약호르몬을 처리하면 일시적으로 휴면이 타파되고 산란이 이루어졌으나 탈피호르몬은 아무런 영향도 미치지 못했다.

묘판말기(苗板末期)부터 본답초기(本畓初期)에 걸쳐 벼 농사(農事)에 피해(被害)가 심(甚)한 벼잎벌레에 대(對)한 발생소장조사((發生消長調査), 생활사(生活史), 기주식물(寄主植物), 피해해석(被害解析) 방제법(防除法)을 구명(究明)하고자 1976년(年)부터 1983년(年)까지 강원도(江原道) 농촌진흥원(農村振興院)에서 수행(遂行)한 시험성적(試驗成績)을 요약(要約)하면 다음과 같다. 1. 벼잎벌레 성충(成蟲)의 발생최성기(發生最盛期)는 5월(月) 하순(下旬)이고 유충(幼蟲)의 발생최성기(發生最盛期)는 6월(月) 중순경(中旬傾)이였다. 2. 벼잎벌레의 분포(分布)는 산간지대(山間地帶)부터 평야지대(平野地帶)에 이르기 까지 강원도(江原道) 전역(全域)에 분포(分布)되어 있다. 3. 벼잎벌레는 주(主)로 묘판말기(苗板末期)인 5월(月) 하순(下旬)부터 벼에 비래(飛來)하여 산란(産卵)하며 6월(月) 하순(下旬)까지 생존(生存)하고 있는데 난기간(卵期間)은 9일(日), 유충기간(幼蟲期間)은 16일(日), 용기간(踊期間)은 9일(日)이였다. 4. 기주식물(寄主植物)을 밝히기 위하여 8종(種)의 잡초(雜草)를 공시(供試)한 결과(結果) 나조겹풀만이 벼잎벌레에 가해(加害)되었다. 5. 벼잎벌레에 의(依)한 수량감수(收量減收)는 였으며 피해정도(被害程度)가 심(甚)하고 가해시기(加害時期)가 늦을수록 감수(減收)가 심(甚)했다. 6. 벼잎벌레 방제약제(防除藥劑)로는 펜치온유제(乳劑), 파프유제(乳劑), 지오신입제(粒劑), 파라치온입제(粒劑)가 선정(選定)되었다.