Abstract:
In Brazil, the production of beneficial microorganisms by growers exclusively for their own use is a practice known as \"on-farm production\". Regarding on-farm bioinsecticides, they were initially deployed for pests of perennial and semi-perennial crops in the 1970s but, since 2013, their use has extended to pests of annual crops such as maize, cotton, and soybean. Millions of hectares are currently being treated with these on-farm preparations. Local production reduces costs, meets local needs, and reduces inputs of environmentally damaging chemical pesticides, facilitating establishment of more sustainable agroecosystems. Critics argue that without implementation of stringent quality control measures there is the risk that the on-farm preparations: (1) are contaminated with microbes which may include human pathogens or (2) contain very little active ingredient, impacting on field efficacy. The on-farm fermentation of bacterial insecticides predominates, especially that of Bacillus thuringiensis targeting lepidopteran pests. However, there has been a rapid growth in the past 5 years in the production of entomopathogenic fungi, mostly for the control of sap-sucking insects such as whitefly (Bemisia tabaci (Gennadius)) and the corn leafhopper (Dalbulus maidis (DeLong and Wolcott)). In contrast, on-farm production of insect viruses has seen limited growth. Most of the ca. 5 million rural producers in Brazil own small or medium size properties and, although the vast majority still do not practice on-farm production of biopesticides, the topic has aroused interest among them. Many growers who adopt this practice usually use non-sterile containers as fermenters, resulting in poor-quality preparations, and cases of failure have been reported. On the other hand, some informal reports suggest on-farm preparations may be efficacious even when contaminated, what could be explained, at least partially, by the insecticidal secondary metabolites secreted by the pool of microorganisms in the liquid culture media. Indeed, there is insufficient information on efficacy and mode of action of these microbial biopesticides. It is usually the large farms, some with > 20,000 ha of continuous cultivated lands, that produce biopesticides with low levels of contamination, as many of them possess advanced production facilities and have access to specialized knowledge and trained staff. Uptake of on-farm biopesticides is expected to continue but the rate of adoption will depend on factors such as the selection of safe, virulent microbial strains and implementation of sound quality control measures (compliance with emerging Brazilian regulations and international standards). The challenges and opportunities of on-farm bioinsecticides are presented and discussed.
摘要:
在巴西,种植者专门为自己使用生产有益微生物是一种被称为“农场生产”的做法。关于农场生物杀虫剂,它们最初在1970年代被部署用于多年生和半多年生作物的害虫,但是,自2013年以来,它们的使用已经扩展到玉米等一年生作物的害虫,棉花,和大豆。目前正在用这些农场制剂处理数百万公顷的土地。本地生产降低了成本,满足当地需求,减少对环境有害的化学农药的投入,促进建立更可持续的农业生态系统。批评者认为,如果不实施严格的质量控制措施,农场制剂存在以下风险:(1)被可能包括人类病原体的微生物污染或(2)含有很少的活性成分,影响田间功效。细菌杀虫剂的农场发酵占主导地位,特别是针对鳞翅目害虫的苏云金芽孢杆菌。然而,在过去的5年里,昆虫病原真菌的产量快速增长,主要用于控制吸汁昆虫,例如粉虱(烟粉虱(Gennadius))和玉米叶斗(Dalbulusmaidis(DeLong和Wolcott))。相比之下,昆虫病毒的农场生产增长有限。大多数CA。巴西有500万农村生产者拥有中小型房地产,尽管绝大多数仍然没有进行生物农药的农场生产,这个话题引起了他们的兴趣。许多采用这种做法的种植者通常使用非无菌容器作为发酵罐,导致制剂质量差,并且已经报告了失败的案例。另一方面,一些非正式报告表明,即使受到污染,农场准备工作也可能有效,什么可以解释,至少部分地,由液体培养基中微生物池分泌的杀虫次生代谢产物。的确,关于这些微生物生物农药的功效和作用方式的信息不足。通常是大型农场,一些拥有超过20,000公顷的连续耕地,产生污染程度低的生物农药,因为他们中的许多人拥有先进的生产设施,并有机会获得专业知识和训练有素的员工。农场生物农药的吸收预计将继续,但采用率将取决于诸如选择安全,和实施良好的质量控制措施(符合巴西新兴法规和国际标准)。介绍和讨论了农场生物杀虫剂的挑战和机遇。