Influences of different damaged degrees of leafminer-infected leaves on the near-infrared spectral reflectance

In order to find out an automatic monitoring method of plant insect pests, leaves infected by the leafminer were studied. Using image processing and spectroscopy analysis technology, near-infrared spectral reflectance of leaves infected by the leafminer was measured; damaged degrees(DD) of leaves and the ratios of the dry and fresh leaf weights(DFLW) were calculated. The regression results between DFLW and the near-infrared spectral reflectance are as follows: R² value between cucumber leaves and the near-infrared spectral reflectance is 0.79 (at 1452 nm) and the tomatoes' is 0.70(at 1450 nm); the R² value between the cucumber's DD and the near-infrared spectral reflectance is beyond 0.81(at 1436～1466 nm), tomato's is beyond 0.69(at 1436～1468 nm), respectively. The experiment and analysis results show that the leaf damaged degrees can be reflected by the near-infrared spectral reflectance of leafminer-infected leaves.