Evaluation of a Dry Extract System Involving NIR Spectroscopy (DESIR) for Rapid Assessment of Pesticide Contamination of Fruit Surfaces

The dry-extract system for (near) infrared (DESIR) technique was implemented using reflectance near-infrared spec-troscopy in context of detection of contact pesticide residues on fruit. Based on chemical structure, spectra features and regression statistics for PLSR models, a product containing metiram and pyraclostrobin was chosen from six pesticides for further consideration. Regression models based on spectra of dry extracts of aqueous solutions and either acetone or water washes of contaminated fruit were encouraging (RMSECV of approximately 0.03 - 0.06 mg a.i.). This level of analytical performance would support the use of the technique as a rapid screening tool, with suspect samples then subject to the reference GC-MS analysis method. However, the PLSR model performance was poor across populations of fruit, suggesting that matrix changes in the solvent wash between sets of fruit is problematic. Further work is required to establish whether sufficient variation can be built into a calibration set to overcome this issue, without degrading model performance to the point where it loses practical application.

火焰原子吸收法间接测定代森锰锌中有效成份的方法研究

本文提出了以原子吸收法间接测定喷克中有效成分含量的新方法。实验结果表明方法具有良好的准确度和精密度。测定快速、简便，相对标准偏差为0．136％．此法与CIPAC法对比，结果满意。

喷克防治苹果主要病害应用技术

喷克（ｍａｎｃｏｚｅｂ）８０％可湿性粉剂６００倍、８００倍、１０００倍室内对苹果轮纹病（Ｐｈｙｓａｌｏｓｐｏｒａｐｉｒｉｃｏｌａ）抑菌效果均达１００％，６００倍、８００倍对苹果斑点落叶病菌（Ａｌｔｅｒｎａｒｉａｍａｌｉ）、炭疽病菌（Ｇｌｏｍｅｒｅｌａｃｉｎｇｕｌａｔａ）亦具显著的抑制效果。人工接菌条件下，８００倍液防治苹果斑点落叶病的实际保护期为１０～１２ｄ，防治苹果轮纹病的有效保护期为８～１０ｄ。田间药效试验示范表明：喷克８０％可湿性粉剂与波尔多液交替使用，对苹果轮纹病、炭疽病和斑点落叶病具有显著的兼治作用，推荐剂量为８００倍液，施药适期为苹果幼果期（谢花后～６月初，连续喷施３次）和着色期（８月中旬～９月中旬，连喷２次）。