Atehnkeng Joseph, Ojiambo Peter S, Ortega-Beltran Alejandro, Augusto Joao, Cotty Peter J, Bandyopadhyay Ranajit
Pathology and Mycotoxin, International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria.
Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, United States.
Front Microbiol. 2022 Nov 24;13:1049013. doi: 10.3389/fmicb.2022.1049013. eCollection 2022.
Aflatoxins, produced by several section species in various crops, are a significant public health risk and a barrier to trade and development. In sub-Saharan Africa, maize and groundnut are particularly vulnerable to aflatoxin contamination. Aflasafe, a registered aflatoxin biocontrol product, utilizes atoxigenic genotypes native to Nigeria to displace aflatoxin producers and mitigate aflatoxin contamination. Aflasafe was evaluated in farmers' fields for 3 years, under various regimens, to quantify carry-over of the biocontrol active ingredient genotypes. Nine maize fields were each treated either continuously for 3 years, the first two successive years, in year 1 and year 3, or once during the first year. For each treated field, a nearby untreated field was monitored. Aflatoxins were quantified in grain at harvest and after simulated poor storage. Biocontrol efficacy and frequencies of the active ingredient genotypes decreased in the absence of annual treatment. Maize treated consecutively for 2 or 3 years had significantly ( < 0.05) less aflatoxin (92% less) in grain at harvest than untreated maize. Maize grain from treated fields subjected to simulated poor storage had significantly less ( < 0.05) aflatoxin than grain from untreated fields, regardless of application regimen. Active ingredients occurred at higher frequencies in soil and grain from treated fields than from untreated fields. The incidence of active ingredients recovered in soil was significantly correlated ( = 0.898; < 0.001) with the incidence of active ingredients in grain, which in turn was also significantly correlated ( = -0.621, = 0.02) with aflatoxin concentration. Although there were carry-over effects, caution should be taken when drawing recommendations about discontinuing biocontrol use. Cost-benefit analyses of single season and carry-over influences are needed to optimize use by communities of smallholder farmers in sub-Saharan Africa.
黄曲霉毒素由多种作物中的几个节的物种产生，是重大的公共卫生风险，也是贸易和发展的障碍。在撒哈拉以南非洲，玉米和花生特别容易受到黄曲霉毒素污染。Aflasafe是一种注册的黄曲霉毒素生物防治产品，利用尼日利亚本土的产毒不产黄曲霉毒素基因型取代产黄曲霉毒素的菌株并减轻黄曲霉毒素污染。在农民的田地中，对Aflasafe进行了3年的不同方案评估，以量化生物防治活性成分基因型的残留情况。9块玉米田分别连续处理3年、前两年连续处理（第1年和第3年）或在第1年处理一次。对于每块处理过的田地，监测附近一块未处理的田地。在收获时以及模拟储存条件较差后，对谷物中的黄曲霉毒素进行定量分析。在没有年度处理的情况下，生物防治效果和活性成分基因型的频率会下降。连续处理2年或3年的玉米在收获时谷物中的黄曲霉毒素含量比未处理的玉米显著减少（<0.05）（减少92%）。无论施用方案如何，经过模拟储存条件较差处理的田地收获的玉米籽粒中的黄曲霉毒素含量均显著低于未处理田地收获的玉米籽粒。处理过的田地的土壤和谷物中活性成分的出现频率高于未处理的田地。土壤中回收的活性成分的发生率与谷物中活性成分的发生率显著相关（r = 0.898；P < 0.001），而谷物中活性成分的发生率又与黄曲霉毒素浓度显著相关（r = -0.621，P = 0.02）。尽管存在残留效应，但在提出停止使用生物防治的建议时应谨慎。需要对单季和残留影响进行成本效益分析，以优化撒哈拉以南非洲小农户社区的使用。
