The serious emergence of chemical-mediated residual toxicity and insect resistance have been enforced the regulation of synthetic pesticides. Future decisions to select more realistic control options probably depend on the speed of technological development in chemical and biological pesticides. Now, a strategic collaboration between synthetic pesticides and biopesticides has been progressed, such as distribution and R&D in collaboration and M&A for obtaining microbial resources. Recently registered microbial pesticides are entomopathogenic fungi in pest management. A concept of e-biopesticide could be properly combined with digital agriculture and accelerate the use of biological control agents in the future farming.
Insect pests have been a serious problem over many years and remain a major threat for food production. Although chemical pesticides are major pest control strategies, use of microorganisms such as entomopathogenic bacteria, fungi, viruses and nematodes have continuously increase last few decades to minimize the use of agrichemicals. According to BBC research, the global biocontrol market was about $2.1 billion in 2011, and this is expected to rise $3 ~ 4 billion by 2017. Over 50 entomopathogens are commercially produced and used augmentatively as microbial pesticides. About 175 biopesticide active ingredients and 700 products have been registered worldwide. Bacillus thuringiensis (Bt), Beauveria bassiana, Metarhizium spp., nuclear polyhedrosis virus and Steinernema spp. are the most popular control agents used in plant protection. Among the microbial control agents Bt products have more than 50% of market share. In Korea, only 13 environmentally-friendly crop protectants were registered for insect pest control in 2015. Market share is very low and has grown slowly. We will discuss how we can expand the market with our techniques.
An entomopathogenic bacterium, Xenorhabdus nematophila (Xn), is symbiotic to a nematode, Steinernema carpocapsae, and exhibits high pathogenicity to lepidoptera insects. Its metabolites released into the bacterial culture broth and also virulent in oral especially when they are treated with Bacillus thuringiensis (Bt). This study devised a high efficacy microbial insecticide by combining Xn culture broth and Bt. Bt kurstaki (Btk) exhibited relatively higher pathogenicity to Plutella xylostella than Spodoptera exigua larvae. By contrast, Bt aizawai (Bta) showed a reverse pathogenicity pattern. Phase Ⅰ type of Xn (XnK1) was isolated from S. carpocapsae Pochun and exhibited high pathogenicity than phase Ⅱ bacteria. Three bacterial mixtures of Bta+XnK1, Btk+XnK1, and Bta+Btk+XnK1 were prepared and analyzed in their target insects. Bta+XnK1 showed higher pathogenicity than those of Bta alone or Btk+XnK1 in P. xylostella. Btk+XnK1 showed higher pathogenicity than those of Btk alone or Bta+XnK1 in S. exigua. Bta+BtK+XnK1 showed high pathogenicity against both P. xylostella and S. exigua.
Historically in Japan, studies on the diseases of the silkworm, Bombyx mori, as a factor affecting the well-being of the silk industry, have dominated insect pathology. However, work by Hidaka (1933) demonstrated the possibility of controlling the pine moth, Dendrolimus spectabilis, with the fungus Beauveria bassianaand since then, various attempts have been made to develop a method to control insect pests using insect pathogens (Table 1, 2). The cypovirus product, Matsukemin, was the first microbial control product to be registered in 1974, and inactive and live Bacillus thuringiensis products were also registered and put on the market as pesticides in 1980 and 1981, respectively (Table 3). Currently, there are 32 microbial insecticides on the market that constitute slightly less than 2% of all insecticides used in Japan (Table 4, Fig.1, 2). Adoption of biopesticides is likely to increase in the near future due to scientific advances and several new government policies that encourage the use of alternative pest control products.
담배거세미나방 핵다각체병바이러스를 white carbon 제제, molasses 제제 및 White carbon-molasses 혼합제등 3종의 바이러스살충제로 만들어 제제의 살포방법, 살포효과 및 잔류효과를 폿트 및 콩포장에서 살충효과를 비교하였다. 바이러스 살충채 살포는 콩잎 표면 살포시 약 5일, 이변 살포시 약 12일까지 60% 이상의 살충효과가 지속되었다. 폿트식재 콩잎을 이용한 바이러스살충제의 살포효과는 molasses 제제와 with carbon 제제에서 모두 97% 이상의 살충효과가 있었으나 molasses성분을 포함한 제제는 햇빛에 의해 일부 콩잎에 약해를 보였다. 바이러스살충제 살포 1 시간 후 빗물 처리에 의한 영향은 빗물 무처리와 큰 차이가 없이 90% 이상의 살충효과가 있었다. 야외 콩 포장에서 바이러스살충제의 살포효과는 3종의 제제 모두 90%이상의 살충율이었 며, 유기합성농약보다 7일 늦게 효과가 나타난 반면 2주 이상 효과가 지속되었다.
담배거세미나방 핵다각체병바이러스에 섭식촉진물질, 다각체 침전방지제 및 전착물질과 자외선 차단제를 첨가하여 만든 3종의 바이러스 살충제를 담배거세미나방 유충에 먹여 제제별로 살충 효과를 비교하였다. 바이러스 살충제에 설탕농도 1-5% 첨가로 섭식촉진이 증대되어 살충효과가 높았으며, 바이러스의 불활화 차단효과도 있었다. 살충제 제형에 따른 바이러스 침전방지는 polyvinylalcohoI 0.5%, 식물체 전착성은 Triton X -100 0.1 %에서 효과가 좋았다. 자외선차단제의 양은 white carbon은 100 L 당 800 g, molasses는 30%첨가에서 바이러스의 불활화가 감소되었으며 white carbon-molasses 혼합제는 white carbon 500 g, molasses 10%의 비율에서는 살충효과가 약간 감소하였으나 세 제제 모두 살포 3일후 95%이상의 살충율을 보였다. White carbon 체제는 molasses 제제보다 다각체 포매가 뚜렷하여 잔류효과가 증대되었으나 유충의 섭식은 molasses제제에서 촉진되었다.