Fahrentrapp Johannes, Ria Francesco, Geilhausen Martin, Panassiti Bernd
Institute of Natural Resource Sciences, ZHAW Zurich University of Applied Sciences, Wädenswil, Switzerland.
Independent Researcher, Munich, Germany.
Front Plant Sci. 2019 May 15;10:628. doi: 10.3389/fpls.2019.00628. eCollection 2019.
Fungal leaf diseases cause economically important damage to crop plants. Protective treatments help producers to secure good quality crops. In contrast, curative treatments based on visually detectable symptoms are often riskier and less effective because diseased crop plants may develop disease symptoms too late for curative treatments. Therefore, early disease detection prior symptom development would allow an earlier, and therefore more effective, curative management of fungal diseases. Using a five-lens multispectral imager, spectral reflectance of green, blue, red, near infrared (NIR, 840 nm), and rededge (RE, 720 nm) was recorded in time-course experiments of detached tomato leaves inoculated with the fungus and mock infection solution. Linear regression models demonstrate NIR and RE as the two most informative spectral data sets to differentiate pathogen- and mock-inoculated leaf regions of interest (ROI). Under controlled laboratory conditions, bands collecting NIR and RE irradiance showed a lower reflectance intensity of infected tomato leaf tissue when compared with mock-inoculated leaves. Blue and red channels collected higher intensity values in pathogen- than in mock-inoculated ROIs. The reflectance intensities of the green band were not distinguishable between pathogen- and mock infected ROIs. Predictions of linear regressions indicated that gray mold leaf infections could be identified at the earliest at 9 h post infection (hpi) in the most informative bands NIR and RE. Re-analysis of the imagery taken with NIR and RE band allowed to classify infected tissue.
真菌性叶部病害会对农作物造成重大经济损失。保护性处理有助于生产者获得优质作物。相比之下，基于肉眼可检测症状的治疗往往风险更大且效果较差，因为患病作物可能出现病害症状时已为时过晚，无法进行治疗。因此，在症状出现之前进行早期病害检测可以实现对真菌病害更早、因而更有效的治疗管理。使用五镜头多光谱成像仪，在接种真菌和模拟感染溶液的离体番茄叶片的时程实验中记录了绿色、蓝色、红色、近红外（NIR，840 nm）和红边（RE，720 nm）的光谱反射率。线性回归模型表明，近红外和红边是区分病原体接种和模拟接种叶感兴趣区域（ROI）的两个最具信息性的光谱数据集。在受控实验室条件下，与模拟接种的叶片相比，收集近红外和红边辐照度的波段显示受感染番茄叶组织的反射强度较低。在病原体接种的ROI中，蓝色和红色通道收集到的强度值高于模拟接种的ROI。病原体接种和模拟感染的ROI之间绿色波段的反射强度没有差异。线性回归预测表明，在最具信息性的近红外和红边波段，最早可在感染后9小时（hpi）识别出灰霉病叶感染。对近红外和红边波段拍摄的图像进行重新分析可以对受感染组织进行分类。
