Biological control has emerged due to the side effects of chemical control such as residual and toxicity. One of the biological controls is entomopathogenic fungi. The entomopathogenic fungus used in this study was first detected in the insectary. The fungus was identified as Lecanicillium sp. based on the sequences of the ITS1 and 2 regions. Lecanicillium sp. infects aphids, scale insects and whiteflies, especially Myzus persicae and Aphis gossypii. In this study, we characterized the fungal phenotype, growth condition, and pathogenicity against green peach aphid. Mycelial growth of Lecanicillium sp. was 12.79±0.46 mm diameter during 7days on potato dextrose agar at 25℃. In addition, the fungus was able to annihilate 100% green peach aphids, after 8days of inoculation. Ultimately, this study would be provide new information on Lecanicillium sp. and suggest the potential utilization of this fungus as a biological control agent.

목화진딧물(Aphis gossypii Glover) (Hemiptera: Aphididae)은 감귤에서 그을음병을 유발하여 감귤 과실에 경제적으로 피해를 주는 해충이다. 본 연구는 무가온 하우스 감귤에서 계절초기 목화진딧물이 어떠한 경로를 거쳐서 감귤나무에 정착하는지 구명하기 위하여 수행하였다. 감귤나무에서 진딧물 월동알 조사결과 가을순이 난 여름순에서 많이 발견되었는데 월동알은 대부분 조팝나무진딧물이었으며, 목화진딧물 월동알은 발견되지 않았다. 봄순에 정착하는 목화진딧물 유시형 성충은 크게 4월 하순(조기비산)과 5월 하순(지연비산)에 두 차례 관측되었다. 지연비산은 완전생활형 간모세대에서 유시형이 출현하는 시기와 일치하였다. 조기비산 시기에 황색수반트랩에서도 목화진딧물 유시형 성충이 유살되었는데 확실하지는 않으나 월동잡초에서 잔존하고 있던 불완전세대 개체군으로 추정되었다. 결과적으로 무가온 하우스 감귤에서 목화진딧물의 정착은 불완전생활형의 조기비산과 완전생활형의 지연비산으로 일어난다는 것이 확인되었다.

오이에서 가장 피해가 심한 해충인 목화진딧물과 꽃노랑총채벌레에 방제를 위하여 사용하고 있는 천적인 콜레마니진디벌과 미끌애꽃노린재에 대하여 노균병과 흰가루병 약제의 저독성을 평가하여 살균제와 동시에 활용한 목화진딧물과 꽃노랑총채벌레에 대한 천적의 방제효과를 조사하였다. 47종 살균제 중 DBEDC, hexaconazole, pyraclostrobin, tribasic copper sulfate, triflumizole, chlorothalonil, flusilazole, folpet, carbendazim+diethofencarb, cymoxanil+fenamidone, trifloxystrobin은 콜레마니진디벌 머미에 50% 이상의 독성을 보였고 저독성 살균제 중 azoxystrobin이 노균병과 흰가루병을 동시에 방제할 수 있어 천적과의 동시활용 약제로 선발하였다. 꽃노랑총채벌레와 목화진딧물은 천안과 공주에서 4월 상순 동시에 급격히 밀도가 증가하였고, azoxystrobin 50% 액상수화제를 10일간격으로 계속 방제 하면서 콜레마니진디벌을 진딧물 발생초기 1주간격 3회, 미끌애꽃노린재를 발생초기 1주간격 3회 방사 후 천적 밀도를 조사한 결과 목화진딧물과 꽃노랑총채벌레의 밀도를 억제하면서 콜레마니진디벌 머미는 하엽당 최대 18마리, 미끌애꽃노린재는 꽃당 0.5마리를 나타내어 azoxystrobin이 콜레마니진디벌과 미끌애꽃노린재의 밀도형성에 악영향을 주지 않았다. 시설오이에서 콜레마니진디벌과 미끌애꽃노린재에 안전한 선택약제와 천적을 동시 이용할 경우 효과적인 진딧물과 총채벌레 방제가 가능할 것이다.

The melon and cotton aphid Aphis gossypii Glover (Hemiptera; Aphididae) is one of the most serious pests worldwide. We surveyed insecticide susceptibility in A. gossypii field populations to 12 insecticides (6 neonicotinoids, 3 pyrethroids and 3 others) to examine resistance ratios. The levels of insecticide resistance were extremely high, especially to neonicotinoids, such as acetamiprid, clothianidin, thiacloprid and imidacloprid. To identify the neonicotinoid resistance mechanisms, we used an imidacloprid-resistant (IMI-R) strain as a model strain. IMI-R showed an extremely high resistance ratio and also cross-resistance to all the test neonicotinoids. However, there was little or no cross-resistance to the other insecticides, including sulfoxaflor. Synergist tests and enzyme activity assays suggested the absence of resistance mechanisms based on enhanced detoxification enzymes, such as cytochrome P450, esterase and glutathione S-transferase. One point mutation was found in the beta1 subunit loop D region of the nicotinic acetylcholine receptor (nAChR) of the IMI-R strain. This R81T point mutation was also found in field populations collected from 5 regions. Therefore, the R81T point mutation was identified as an important mechanism of imidacloprid resistance in A. gossypii.

In terms of aphid species identification, both host plant association and morphological characteristics are crucial factors. However, aphids in the genus Aphis Linnaeus (Hemiptera: Aphididae) often are cryptic in morphology due to their rapid radiation. Moreover, overlapping host plant species can make difficult situation worse. Three cryptic species Aphis gossypii Glover, Aphis glycines Matsumura, and Aphis rhamnicola sp. nov. occur together on the Buckthorn, Rhamnus spp. in the overwintering season in Korea. Due to lacking informative morphological characters and host plant sharing, the new species recently has been recognized as a distinct species. In this study, A. rhamnicola sp. nov. on various host plants was compared with the primary host sharing species, A. gossypii and A. glycines, based on morphological and molecular characteristics. In the results, there were significant genetic differences between three species, despite the high similarities in morphology. Our results provide strong evidence for establishing new species, which seems to be a typical heteroecious species that alternates between only primary host, Rhamnus spp., and various secondary hosts. We describe a new species, A. rhamnicola sp. nov., for apterous and alate vivipara, fundatrix, ovipara, and gynopara, including diagnostic key for host sharing species in genus Aphis.

The cotton aphid, Aphis gossypii (Glover), is one of the most serious pest in the cultivation of various vegetables. A highly imidacloprid-resistant field population (CA-L) was collected from cucumber at Gangwha island in 4th August 2011. Even though neonicotinoid insecticides especially imidacloprid were sprayed six times during June and July, aphid density was too high to be counted. IEF and 2DE analyses revealed that general esterase isozyme (pI. 5) in CA-L were dramatically overexpressed and more isozyme spots identified in CA-L compared to susceptible (CA-S) strain. To identify differentially expressed genes in CA-L, comparative transcriptome analyses based on GS-FLX were conducted with total RNA extracted from CA-L, which generated ca. 143 Mb reads. Previously reported, comparative transcriptome analyses performed in imidacloprid resistant (CA-IR) and CA-S. The comparative transcriptome analyses re-investigated after all data sets were combined together. As previously reported, seven ATP-binding cassette (ABC) transporter genes were newly identified in A. gossypii, among which only ABCC9 gene was highly expressed in CA-IR and L. These results suggested that ABCC subfamily associated with imidacloprid resistance in A. gossypii.