title: Remotely sensing arthropod and nutrient stressed plants: a case study with nitrogen and cotton aphid (Hemiptera: Aphididae).
abstract: Remote sensing can be used in combination with ground sampling to detect aphid- (Aphis gossypii Glover) infested cotton (Gossypium hirsutum L.). Changes in wavelengths in the near-infrared (NIR) have proven useful for such detection, but these changes can be confused with  other factors stressing plants, such as water deficiency and nutrient status. This study was designed to test the utility of this technology to distinguish between two factors stressing plants: nitrogen deficiency and aphids. Field plots were created by applying varying rates of nitrogen to  cotton at different dates in the growing season in 2003 and 2004. Subplots were created by applying disruptive insecticides, which increased aphid populations in a portion of the subplots. Airplane and satellite remote sensing data in 2003 and 2004 were supplemented with ground sampling of  aphid populations in both years. Insecticide application, nitrogen application rate and date influenced aphid abundance. Cotton with higher aphid populations could be distinguished from cotton with natural aphid infestations independent of plant nitrogen status using a NIR wavelength in 2003  and a proprietary 2004 index. Complex distinctions among varying nitrogen treatments and aphid abundance were not possible using this data. In the future, possible confounding factors should be investigated from the perspective of their change on crop physiology before remote sensing can be  used in an integrated pest management (IPM) program.
authors: Department of Entomology, North Carolina State University, Vernon G. James Research and Extension Center, 207 Research Station Rd., Plymouth, NC 27962, USA. ddreisig@ncsu.edu
authors: Dominic D
authors: DD
authors: Reisig
authors: Larry D
authors: LD
authors: Godfrey
mesh_terms: D000818:Animals; D001042:Aphids / Q000502:physiology*; D005308:Fertilizers; D003368:Gossypium / Q000378:metabolism / Q000469:parasitology*; D006790:Host-Parasite Interactions; D009584:Nitrogen / Q000378:metabolism*; D058998:Remote Sensing Technology; D013312:Stress, Physiological
chemical_list: D005308:Fertilizers; D009584:Nitrogen