Robotic agricultural instrument for automated extraction of nematode cysts and eggs from soil to improve integrated pest management

Abstract Soybeans are an important crop for global food security. Every year, soybean yields are reduced by numerous soybean diseases, particularly the soybean cyst nematode (SCN). It is difficult to visually identify the presence of SCN in the field, let alone its population densities or numbers, as there are no obvious aboveground disease symptoms. The only definitive way to assess SCN population densities is to directly extract the SCN cysts from soil and then extract the eggs from cysts and count them. Extraction is typically conducted in commercial soil analysis laboratories and university plant diagnostic clinics and involves repeated steps of sieving, washing, collecting, grinding, and cleaning. Here we present a robotic instrument to reproduce and automate the functions of the conventional methods to extract nematode cysts from soil and subsequently extract eggs from the recovered nematode cysts. We incorporated mechanisms to actuate the stage system, manipulate positions of individual sieves using the gripper, recover cysts and cyst-sized objects from soil suspended in water, and grind the cysts to release their eggs. All system functions are controlled and operated by a touchscreen interface software. The performance of the robotic instrument is evaluated using soil samples infested with SCN from two farms at different locations and results were comparable to the conventional technique. Our new technology brings the benefits of automation to SCN soil diagnostics, a step towards long-term integrated pest management of this serious soybean pest.

摘要：大豆是保障全球粮食安全的重要作物。每年，多种大豆病害均会造成大豆产量下降，其中尤以大豆孢囊线虫（Soybean Cyst Nematode, SCN）为甚。由于该病害无明显地上部症状，田间难以通过目视检测发现其发生情况，更遑论估算其种群密度。目前评估SCN种群密度的唯一可靠方法，是直接从土壤中提取SCN孢囊，再从孢囊中分离卵粒并计数。此类提取工作通常在商用土壤分析实验室与高校植物诊断诊所开展，需反复完成筛分、洗涤、收集、研磨与净化等步骤。本研究介绍一款机器人化仪器，可复刻并自动化传统方法的全流程：从土壤中提取线虫孢囊，并进一步从回收的孢囊中分离卵粒。该仪器集成了载物台驱动系统、机械爪操控单个筛网位置的机构，可从悬浮于水中的土壤中回收孢囊及孢囊尺寸的颗粒物，并通过研磨孢囊释放其内的卵粒。所有系统功能均通过触摸屏交互软件进行控制与操作。本研究使用采自两个不同地点农场的感染SCN的土壤样品对该仪器的性能进行评估，结果显示其表现与传统技术相当。本新技术为SCN土壤诊断带来了自动化优势，为这一重大大豆害虫的长期害虫综合防治迈出了关键一步。