Possibilities of cucumber powdery mildew detection by visible and near-infrared spectroscopy
Laen...
Kuupäev
2022
Kättesaadav alates
Autorid
Alsiņa, I.
Bimšteine, G.
Dubova, L.
Kaņeps, J.
Kviesis, K.
Bankina, B.
Dūma, M.
Avotiņš, A.
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Estonian University of Life Sciences
Abstrakt
Cucumbers are one of the most demanded and widely grown greenhouse vegetables.
Important factors that influence quality and quantity of yield are diseases. Powdery mildew
(caused by Podosphaera xanthii and/or Golovinomyces cichoracearum), is one of the
most harmful cucumber diseases. Early detection of mildew via non-destructive methods can
optimize schemes of fungicide application. The study aimed to find regularities in the reflected
light spectra, indices described in the literature, and severity of mildew. Plants were grown in the
polycarbonate greenhouse under artificial lighting in a 16 h photoperiod with PAR at the tips of
plants 200 ± 30 µmol m-2 s-1. Leaf reflection spectra were obtained using spectroradiometer
RS-3500 (Ltd. Spectral Evolution). Spectral range 350–2,500 nm, bandwidth 1 nm. The severity
of cucumber mildew was evaluated using 10 point scale (0- no symptoms, … 9 - the plant is
dead). The vegetation indices found in the literature have been calculated. The obtained results
show that the calculated indices have different sensitivities. The strongest correlation between the
degree of cucumbers infection with powdery mildew and the light reflectance spectrum was found
in the green range of visible light around 550 nm. Disease-Water Stress Index-2 (DSWI-2),
Structure Intensive Pigment Index (SIPI), and Normalized Difference Vegetation Index (NDVI)
are the most suitable indices for determining powdery mildew in cucumbers. New indices for
detection of powdery mildew have been created. None of the studied indices allows determining
the powdery mildew at the early stages of disease development when powdery mildew severity
is below 10%.
Kirjeldus
Received: July 16th, 2021 ; Accepted: November 6th, 2021 ; Published: February 1st, 2022 ; Correspondence: Ina.Alsina@llu.lv
Märksõnad
Cucumis sativus, NDVI, SIPI, DSWI, Podosphaera xanthii, Golovinomyces cichoracearum, articles