Linear correlation between spectral reflectance and disease indexes of wheat powdery mildew at GS 10.5.3, 10.5.4 and 11.1 in 2009–2010 and 2010–2011 seasons for the plant density 1 (60 kg seed ha^-1) (A) and density 2 (120 kg seed ha^-1) (B).

<p>Linear correlation between spectral reflectance and disease indexes of wheat powdery mildew at GS 10.5.3, 10.5.4 and 11.1 in 2009–2010 and 2010–2011 seasons for the plant density 1 (60 kg seed ha^-1) (A) and density 2 (120 kg seed ha^-1) (B).</p

Vegetation indices used in this study and their method of calculation.

<p>R_R = Reflectance of red band with the range from 650–680 nm</p><p>R_NIR = Reflectance of near-infrared band with the range from 780–890 nm</p><p>R_G = Reflectance of green band with the range from 560–600 nm.</p><p>Vegetation indices used in this study and their method of calculation.</p

Progress curves of wheat powdery mildew epidemics on plant density 1 (60 kg seed/ha) (A) and density 2 (120 kg seed/ha) (B) with different concentrations of fungicide applications in Langfang City in 2009–2010 and 2010–2011 seasons.

<p>Disease severity was assessed (0–9 scale) at GS 10.5.3, 10.5.4 and 11.1.</p