Since the gene expression interference induced by dsRNA was discovered, dsRNA has been considered as an antiviral agent and pesticide to protect beneficial insects and crops, respectively. Recently, dsRNA was classified as IRAC mode of action group 35, and the first dsRNA pesticide, Calatha of GreenLight Bioscience, has been approved by EPA. Also an animal drug for Asian honeybee, HoneyGuard-R of Genolution is about to be approved by APQA. During the last two decades, hundreds of papers already had demonstrated the application and capability of dsRNA for agriculture, however, we have just a few commercialized products at hand at this moment. It is time to understand the processes, hurdles and limitations on the industry side that are indispensable for the development, registration and commercialization of dsRNA-based products.

The global biopesticide market was estimated to become about 4% of the total crop protection market in 2015, mainly due to variability of their efficacy, narrow spectrum or difficulties in long-term storage. Therefore, many people focus on overcoming these issues as a big trend. Suggested solutions include the investigation of synergy between microorganisms, the use of genetic engineering, improving the pesticide life shelf, etc. As a result, biopesticides market has grown by more than 17% over the last decade. In this context and aiming to develop new entomopathogenic fungi–based pest management tools, we constructed a fungal library by isolating insect pathogenic fungi from soil. A total of 581 isolates belonging to 35 species were isolated and characterized. Beauveria bassiana was the most abundant, representing 38.55% of the total strains, followed by Metharizium anisopliae (22.55%) and bubillosa (8.6). …% of the total isolates were highly virulent against Tenebrio molitor killing most of the treated insects in 2 to 3 days.

2010년대 들어 화학물 기반의 작물보호제에대한 환경독성 및 잔류 문제의 대두, 병해충에 대한 저항성 증대와 이에 따른 신규 작물보호제 개발 비용의 증가 등은 바이오 작물보호제에 대한 관심을 증가시키고 있다. 특히 Bayer의 AgraQuest 인수, BASF의 Becker Underwood인수, 신젠타의Pasteuria Bioscience 인수나 Monsanto와 Novozyme의 BioAg., FMC와 Chr. Hansen 등의 기술 및 제품개발 협력관계 구축 등은 바이오 작물보호제에 대한 다국적 작물보호제 기업의 높은 관심을 보여주는 것이다. 본 발표에서는 미생물을 활용한 글로벌 바이오 작물보호제 개발 동향 및 팜한농에서 개발한 바이오 작물보호제 개발 사례를 소개하고 향후 바이오 작물보호제 산업화를 위해 요구되는 사항들을 정리하여 논의하고자 한다.

Bacillus thuringiensis (Bt) is a gram-positive and spore-forming bacterium that produces parasporal inclusions containing Cry and Cyt proteins during sporulation. These inclusions or proteins are highly toxic to lepidopteran, dipteran, coleopteran larvae, and nematodes. Because of their selectable specificity and safety to non-target organisms and environment, Bt is considered as a valuable and safe alternative to chemical pesticides for eradication of insect pests. Bt biopesticide products has been commercialized and used very widely and successfully in agriculture, forestry and medical care markets since 1930s. In Korea, the screening for isolation of new Bt strains such as Bt Nt0423 (Tobbagi) and Bt GB-413 (Solbichae) have been performed and their commercial products were launched in agricultural markets. In terms of public health, mosquito larvicidal products made by Bt subsp. israelensis have been registered by Korean ministry of food and drug safety and used since 1995. Recently, a new mosquitocidal serovar (H3a3b3d), Bt subsp. mogi was isolated and its molecular characteristics were analyzed. In our opinion, Bt biopesticides might be still an effective and safe tool for insect pest control in agriculture and public health. Key words: Bacillus thuringiensis, biopesticide, Bt subsp. israelensis, mosqui

Biopesticides are pesticdide derived from natural materials such as animals, plants, bacteria, and certain minerals. Microorganism such as a bacterium, virus, fungus, or microscopic nematode worms can be used in agricultural practices to control of elimate pests that can inflict damage to a plant. Agents used as biopesticides include parasites, predators, fungi, bacteria and viruses. They are being recommended and used as components of IPM programs in the production of high-value specialty crops such as fruit, nut, vegetable, vine, ornamental, and turf crops. The global pesticide market is growing at a 15.8% for the period of 2012 to 2017. Synthetic insecticide use is projected to continue to decline, particularly with the increased use of GM seeds. GM crops are competiong with biopesticides due to disease and pest resistance and complementing for production of chemical residue free crops. Biopesticedes represent a strong growth area in the global pesticide market. Low registration cost and time for development of new active ingredient are major growth drives for the biopesticides market. Bacterial biopesticides control over 70% of microbial biopesticdes market share. Bacillus thuringiensis (Bt) is the most popular bioinsecticide worldwide. The global market for botanical biopesticide is estimated to grow at a CAGR of 14% and semio-chemicals is expected to grow at a CAGR of 16.1% from 2012 to 2017. The global microbial biopesticides market was valued at $862 million in 2011 and is expected to reach $2,606 million by 2017. Global biopesticides market is dominated by bioinsecticides with around 46% share in 2011.

 ,  , Effect of a new crop protectant ‘Bt-Plus’ on natural enemies was analyzed in this study. Tested natural enemies included two parasitic species of Aphidius colemani and Eretmocerus eremicus, and four predatory species of Harmonia axyridis, Orius laevigatus, Amblyseius swirskii, and Phytoseiulus persimilis. ‘Bt-Plus’ was formulated by combination of three entomopathogenic bacteria (Xenorhabdus nematophila (Xn), Photorhabdus temperata subsp. temperata (Ptt), Bacillus thuringiensis (Bt)) and bacterial metabolite (BM). All three types of ‘Bt-Plus’ showed significantly higher toxicities against fourth instar Plutella xylostella larvae than Bt single treatment. Two types of bacterial mixtures (‘Xn+Bt’ and ‘Ptt+Bt’) showed little toxicity to all natural enemies in both contact and oral feeding assays. However, ‘BM+Bt’ showed significant toxicities especially to two predatory mites of A. swirskii and P. persimilis. The acaricidal effects of different bacterial metabolites were evaluated against two spotted spider mite, Tetranychus urticae. All six BM chemicals showed significant acaricidal effects. The BM mixture used to prepare ‘Bt-Plus’ showed a high acaricidal activity with a median lethal concentration at 218.7 ppm (95% confidence interval: 163.2 - 262.3). These toxic effects of bacterial metabolites were also proved by cytotoxicity test against Sf9 cells. Especially, benzylideneacetone, which was used as a main ingredient of ‘BM+Bt’, showed high cytotoxicity at its low micromolar concentration.

Bacillus thuringiensis (Bt) is a bacterial biopesticide against insect pests, mainly lepidopterans. Spodoptera exigua and Plutella xylostella exhibit significant decreases in Bt susceptibility in late larval instars. To enhance Bt pathogenicity, we used a mixture treatment of Bt and other bacterial metabolites which possessed significant immunosuppressive activities. Mixtures of Bt with culture broths of Xenorhabdus nematophila (Xn) or Photorhabdus temperata ssp. temperata (Ptt) significantly enhanced the Bt pathogenicity against late larval instars. Different ratios of Bt to bacterial culture broth had significant pathogenicities against last instar P. xylostella and S. exigua. Five compounds identified from the bacterial culture broth also enhanced Bt pathogenicity. After determining the optimal ratios, the mixture was applied to cabbage infested by late ins tar P. xylostella or S. exigua in greenhouse conditions. A mixture of Bt and Xn culture broth killed 100% of both insect pests when it was sprayed twice, while Bt alone killed less than 80% or 60% of P. xylostella and S. exigua, respectively. Other Bt mixtures, including Ptt culture broth or bacterial metabolites, also significantly increased pathogenicity in the semi-field assays. These results demonstrated that the Bt mixtures collectively names 'Bt-Plus' can be developed into potent biopesticides to increase the efficacy of Bt.

Previously, we have reported a plant extract isolated from Lysimachia foenum gracum Herba as a new environment friendly biopesticide that has the mycelial growth inhibition effect on Magnaporthe oryzae, the pathogenic fungus of the rice blast disease. For the finding of additional biopesticide candidate, we tested the mycelial growth inhibitory effects about 700 species of plant extracts on PDA media. Among them, the extract of Anemarrhena asphodeloides showed prominent inhibitory effect of which IC50 was 139.7 ㎍/㎖. Mycelial radii of M. oryzae were measured on PDA medium containing the four organic solvent fractions isolated from total extract from A. asphodeloides. Ethyl acetate fraction showed the impressive inhibitory effect of IC50, 54.12 ㎍/㎖. In the subsequent rice field test for the total extract of A. asphodeloides, we obtained encouraging 62.0% control rate of rice blast disease without any phytotoxicity. It is almost equivalent to that of chemical pesticides implying the applicability of the extract as a new biopesticide. In further study, the analysis of active ingredients of the extract would be necessary for the development of a new biopesticide and for the verification of cellular mechanism by which the mycelial growth of M. oryzae inhibited.

Thirty five isolates of Trichoderma species collected from seven different locations of Bangladesh were studied for morphological characters and molecular variation. Mycelial diameters of the isolates varied from 8.28 cm to 9.00 cm. Based on colony colour, isolates were grouped into five such as dark green, green, light green, yellowish green and whitish green. Maximum isolates were green and light green. On the basis of growth habit and colony consistency, the isolates were categorized into three groups, in which most species had fast growth and were compact in appearance. PCR-based Random Amplified Polymorphic DNA (RAPD) technique employing 3 decamer primers produced 36 scorable bands of which all (100%) were polymorphic. The co-efficient of gene differentiation (Gst) was 1.0000 reflecting the existence of high level of genetic diversity among the isolates. The Unweighted Pair Group Method of Arithmetic Means (UPGMA) dendrogram constructed from Nei's (1972) genetic distance produced 2 main clusters (13 isolates in cluster 1 and 22 isolates in cluster 2). The result indicating their genetic diversity has opened new possibility of using the most efficient and more isolates of Trichoderma in the preparation of biopesticide and decomposition of municipality waste.