Discrimination of Leafy Spurge (Euphorbia esula L.) and Purple Loosestrife (Lythrum salicaria L.) Based on Field Spectral Data
Abstract
Leafy spurge and purple loosestrife are noxious weeds that displace native vegetation.
Herbicides are often applied to these weeds during flowering, making it ideal to identify them
early in the season. This paper evaluates the spectral separability of the inflorescences and leaves
of these plants from surrounding vegetation. Spectral data of leafy spurge, purple loosestrife, and
surrounding vegetation were collected from sites in southeastern North Dakota. Partial least
squares discriminant analysis (PLS-DA) was used to separate the spectral signatures of these
weeds in the visible and near infrared wavelengths. Using PLS-DA the weeds were discriminated
from their surroundings with R2 values of 0.86 to 0.92. Analysis of the data indicated that the
bands contributing the most to each model were in the red and red edge spectral regions.
Identifying these weeds by the leaves allows them to be identified earlier in the season, allowing
more time to plan herbicide application.