Early season detection and mapping of Pseudomonas syringae pv. actinidae infected kiwifruit (Actinidia sp.) orchards

Figures & data

Table 1 Details of the band information associated with imagery acquired by the multi-spectral sensor systems mounted on the Rapideye satellites (adapted from www.rapideye.com, accessed 14 October 2013).

Band no.	Region	Band range (nm)
1	Blue	440–510
2	Green	520–590
3	Red	630–685
4	Red-edge	690–730
5	Near infrared	760–850

Figure 1 Satellite image of the survey area (Pukehina, New Zealand) taken on 21 October 2010 with the boundaries of the Psa infected vineyards in the region shown.

Table 2 Detection period of Psa infection in Pukehina showing the original classification from Kiwifruit Vine Health (KVH) Inc. and the reclassification performed for this analysis. The total number of KPINs and KBIs associated with the data are also displayed.

KVH Inc grouping	Date range	No. of KPINs ^a with positive Psa	No. of KBIs ^a with positive Psa	Reclassed groupings
A	Nov 2010–Mar 2011	1	4	Early
B	Apr–June 2011	2	4	Early
C	July–Sept 2011	66	288	Early
D	Oct–Dec 2011	207	915	Mid
E	Jan–Mar 2012	41	124	Late
F	Apr–June 2012	8	35	Late
G	Control (No Psa)	66	217	No

^a This is the total number of KPINs/KBIs associated with the KVH Inc data. It includes small orchards, orchards outside the imagery boundary and orchards where imagery is affected by cloud cover. These counts decreased when the data were trimmed prior to analysis.

Table 3 Formula and reference for the vegetative indices (VIs) derived from the extracted image band information. The VIs were calculated at a pixel scale (5 m pixel) using the bands indicated in Table 1.

Name	Abbreviation	Formula	Reference
Simple ratio	SR	NIR/Red	Rouse et al. (1973)
Normalised difference vegetative index	NDVI	(NIR − Red)/(NIR + Red)	Rouse et al. (1973)
Green NDVI	GNDVI	(NIR − Green)/(NIR + Green)	Gitelson & Merzlyak (1998)
Red-edge NDVI	NDRE	(NIR − Red-edge)/(NIR + Red-edge)	Gitelson & Merzlyak (1994)
Modified red-edge NDVI	modNDRE	(NIR − Red-edge)/(NIR + Red-edge − [2 × Blue])	Datt (1999)
Enhanced vegetative index	EVI	(2.5 × [NIR − Red])/(NIR + [6 × Red] − [7.5 × Blue] + 1)	Huete et al. (1994)
Enhanced vegetative index 2	EVI2	(2.5 × [NIR − Red])/(NIR + [2.4 × Red] + 1)	Huete et al. (1997)
Photosynthetic vigour ratio	PVR	Green/Red	Metternicht (2003)
Green chlorophyll index	GCI	(NIR/Green) − 1	Gitelson et al. (2003)
Red-edge chlorophyll index	RECI	(NIR/Red-edge) − 1	Gitelson et al. (2003)
Triangular vegetative index	TVI	0.5 × (120 × [NIR − Green] − 200 × [Red − Green])	Broge & Leblanc (2001)
MERIS terrestrial chlorophyll index	MTCI	(NIR − Red-edge)/(Red-edge − Red)	Dash & Curran (2004)

Figure 2 Plots of the A, χ²; B, percentage of positive prediction; C, percentage of omission errors (false negatives); and D, percentage of commission errors (false positives) from the jack-knifed binomial logistic regression modelling. The circle indicates the mean response across 100 jack-knifed iterations, while the bars indicate the upper and lower 95% confidence levels from the jack-knifed results.

Table 4 The vegetative indices with associated date that were selected from the jack-knifed binomial logistic regression. Only the results for the one- to four-parameter models are presented, as the five- and six-parameter models were not superior (Fig. 2).

Model	Variable	Date	% time selected
1-parameter	PVR	2 Oct	92
	GCI	1 Feb	7
	1 other		1
2-parameter	NDRE	2 Oct	32
	RECI	2 Oct	20
	GNDVI	2 Oct	18
	ModNDRE	2 Oct	13
	MTCI	2 Oct	8
	5 others		<= 4
3-parameter	PVR	1 Feb	39
	GCI	1 Feb	28
	EVI	26 Dec	23
	5 others		<= 5
4-parameter	EVI	26 Dec	47
	TVI Feb 1^st	1 Feb	20
	GCI Feb 1^st	1 Feb	10
	12 others		<= 5

Figure 3 Histogram of the mean photosynthetic vigour ratio (PVR) response from all KBIs on 2 October 2011 associated with either the early (infected) or control (non-infected) groupings (Table 2). Distribution of the non-infected KBIs is shown as the darker shaded region and is typically located in the range of 0.9–1.4.

Rouse JW, Haas RH, Schell JA, Deering DW 1973. Monitoring vegetation systems in the great plains with ERTS. Third ERTS Symposium, NASA SP-351 I: 309–317.

 Google Scholar

Gitelson AA, Merzlyak MN 1998. Remote sensing of chlorophyll concentration in higher plant leaves. Advances in Space Research 22: 689–692. 10.1016/S0273-1177(97)01133-2

 Web of Science ®Google Scholar

Gitelson AA, Merzlyak MN 1994. Spectral reflectance changes associated with autumn senescence of Aesculus Hippocastanum L. and Acer Platanoides L. leaves: spectral features and relation to chlorophyll estimation. Journal of Plant Physiology 143: 286–292. 10.1016/S0176-1617(11)81633-0

 Web of Science ®Google Scholar

Datt B 1999. A new reflectance index for remote sensing of chlorophyll content in higher plants: tests using eucalyptus leaves. Journal of Plant Physiology 154: 30–36. 10.1016/S0176-1617(99)80314-9

 Web of Science ®Google Scholar

Huete A, Justice C, Liu H 1994. Development of vegetation and soil indices for MODIS-EOS. Remote Sensing of Environment 49: 224–234. 10.1016/0034-4257(94)90018-3

 Web of Science ®Google Scholar

Huete AR, Liu H, Batchily K, van Leeuwen W 1997. A comparison of vegetation indices over a global set of TM images for EOS-MODIS. Remote Sensing of Environment 59: 440–451. 10.1016/S0034-4257(96)00112-5

 Web of Science ®Google Scholar

Metternicht G 2003. Vegetation Indices derived from high-resolution airborne videogaphy for precision crop management. International Journal of Remote Sensing 24: 2855–2877. 10.1080/01431160210163074

 Web of Science ®Google Scholar

Gitelson AA, Gritz Y, Merzlyak MN 2003. Relationships between leaf chlorophyll content and spectral reflectance and algorithm for non-destructive chlorophyll assessment in higher plant leaves. Journal of Plant Physiology 160: 271–282. 10.1078/0176-1617-00887

 PubMed Web of Science ®Google Scholar

Broge NH, Leblanc E 2001. Comparing prediction power and stability of broadband and hyperspectral vegetation indices for estimation of green leaf area index and canopy chlorophyll density. Remote Sensing of Environment 76: 156–172. 10.1016/S0034-4257(00)00197-8

 Web of Science ®Google Scholar

Dash J, Curran PJ 2004. The MERIS terrestrial chlorophyll index. International Journal of Remote Sensing 25: 5403–5413. 10.1080/0143116042000274015

 Web of Science ®Google Scholar