利用光谱特征评价莲草直胸跳甲对喜旱莲子草的控制效果

Evaluation of Control Efficiency of Alligator Weed,Alternanthera philoxeroides,by Flea Beetle,Agasicles hygrophila,Based on Canopy Imaging Spectrometer Technique

为建立快速有效的喜旱莲子草生物防治效果评价技术体系,采用基于成像光谱遥感技术的多波段光谱辐射仪,研究了利用冠层光谱特征值评价天敌昆虫莲草直胸跳甲Agasicles hygrophila对喜旱莲子草Alternanthera philoxeroides控制效果的方法。结果表明,莲草直胸跳甲取食引起喜旱莲子草冠层光谱变化,在可见光区绿光波段(中心波长约560 nm)和近红外波段(中心波段810 nm),喜旱莲子草冠层光谱反射率随莲草直胸跳甲密度的增加逐渐下降,而在红光波段(中心波长约660 nm)呈上升趋势。莲草直胸跳甲取食还导致喜旱莲子草植被指数的变化。在近红外区760～810 nm波段莲草直胸跳甲的控制效果与喜旱莲子草冠层光谱反射率呈极显著负相关,相关系数为-0.92,故可将760～810 nm波长范围作为监测莲草直胸跳甲对喜旱莲子草控制效果的敏感波段。

Canopy imaging spectrometer was used to establish a fast and efficient bio-control efficiency evaluation technique for control of alligator weed,Alternanthera philoxeroides by flea beetle,Agasicles hygrophila,by using the multispectral radiometer.Results showed that damage of A.hygrophila resulted in leaf etiolation and changes in canopy spectrum reflectance and vegetation indices of A.philoxeroides.The canopy spectrum reflectance of A.philoxeroides at 560 nm within the green light region and 810 nm within the near-infrared light region decreased with increasing density of A.hygrophila from 0 to 50 pairs per square meter,whereas that at 660 nm within the red light region increased with increasing density of A.hygrophila.The canopy spectrum reflectance at the near-infrared light region of 760 810 nm was significantly negatively correlated with the control efficiency of A.philoxeroides.The results indicated that wavelengths of 760 810 nm can be used to evaluate the control efficiency of A.philoxeroide by A.hygrophila when using a multispectral radiometer.