NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Response of Grape Leaf Spectra to Phylloxera InfestationDuring the 1993 growing season, leaf reflectance and chlorophyll concentrations were monitored with respect to phylloxera (root-louse) infestation in a Napa Valley (California) vineyard. Study plots were established in areas of severely infested, mildly infested, and uninfested sections of the vineyard. A handheld chlorophyll meter, measuring leaf transmittance of near-infrared and red light, confirmed that reduced foliar chlorophyll concentrations were symptomatic of phylloxera stress in the sample vines. Bidirectional reflectance measurements of green and near-infrared light, taken on fresh leaves with a laboratory spectrophotometer, were related to chlorophyll concentration but did not allow discrimination of mildly infested from uninfested vines.
Document ID
20020077949
Acquisition Source
Ames Research Center
Document Type
Contractor Report (CR)
Authors
Johnson, Lee F.
(California State Univ. Seaside, CA United States)
Date Acquired
September 7, 2013
Publication Date
March 1, 1999
Subject Category
Life Sciences (General)
Report/Patent Number
NASA/CR-1999-208765
NAS 1.26:208765
A-9901226
Funding Number(s)
PROJECT: RTOP 233-01-04-05
CONTRACT_GRANT: NCC2-975
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
No Preview Available