Soybean Aphid (Hemiptera: Aphididae) Affects Soybean Spectral Reflectance

Area of Science:

• Agricultural Entomology
• Remote Sensing
• Plant Pathology

Background:

• Soybean aphid (Aphis glycines) is a major soybean pest in the north central United States.
• Current integrated pest management (IPM) relies on scouting, which can be labor-intensive.
• Plant spectral reflectance offers a potential tool for more efficient aphid damage assessment.

Purpose of the Study:

• To determine if soybean aphid feeding affects plant spectral reflectance.
• To evaluate the potential of remote sensing for monitoring aphid injury in soybean.

Main Methods:

• Field trials with controlled soybean aphid infestation levels (early, late, noninfested).
• Weekly monitoring of aphid densities and weekly spectral reflectance measurements.
• Analysis using linear regression to correlate cumulative aphid-days (CAD) with spectral data (RED, NIR, NDVI, chlorophyll content).

Main Results:

• Cumulative aphid-days (CAD) did not affect canopy-level RED reflectance.
• CAD significantly decreased canopy-level NIR reflectance and NDVI.
• Canopy and leaf-level spectral responses were generally consistent; relative chlorophyll content was largely unaffected.

Conclusions:

• Plant spectral reflectance, particularly NIR and NDVI, can be altered by soybean aphid feeding.
• Remote sensing shows promise for detecting soybean aphid damage in soybean.
• This technology could enhance IPM strategies, reducing sampling costs and unnecessary insecticide applications.