Comparative evaluation of long-term storage techniques on viability and virulence of Alternaria solani

Peer review under responsibility of Taibah University.

Figures & data

Table 2 Tests of viability and pathogenicity of stored (at 5 °C and RT^a) target spottissues, cultures and successive sub cultures by spray and splashing methods.

Inoculum type	Test	Method	Temperature
			5 °C					RT
			0 Day	2 M	4 M	8 M	16 M	0 Day	2 M	4 M	8 M	16 M
Target spot	Viability	Culturing	+		+	+	+	+		+	+	−
	Pathogenicity	Spray of culture suspension from target spots	+		+	+	+	+		+	+	−
Target spot powder	Pathogenicity	Spray of powder suspension	+		+	+	+	+		+	+	−
	Pathogenicity	Powder splashing (from soil)	+		+	+	−	+		+	−	−
Target spot powder in soil	Pathogenicity	Powder splashing (from soil)						+		+	+	−
Stored cultures	Viability and Pathogenicity	Suspension spray	+	+	+	+	+	+	+	−	−	−
Successive subcultures	Viability and Pathogenicity	I subculture suspension spray						+
	Viability and Pathogenicity	II subculture suspension spray						+
	Viability and Pathogenicity	III subculture suspension spray						+
	Viability and Pathogenicity	IV subculture suspension spray						+
	Viability and Pathogenicity	V subculture suspension spray						+
	Viability and Pathogenicity	VI subculture suspension spray						+

a RT = room temperature; + = positive result in viability/pathogenicity test; − = negative result in viability/pathogenicity test; empty column indicates experiment not done.

Table 3 Percentage of early blight index (PEBI).

Inoculum type	Pathogenicity test	Temperature
		5 °C					RT^a
		0 Day	2 M	4 M	8 M	16 M	0 Day	2 M	4 M	8 M	16 M
Target spot	Culture suspension spray	85.1 ± 1.1^***		81.6± 2.0^***	79.8 ± 1.3^***	73.2 ± 1.3^***	86.7 ± 1.8^***		79.2 ± 2.3^***	72.4 ± 2.4^***
Target spot powder	Spray	82.5 ± 2.6^***		77.5± 4.2^***	74.6 ± 3.7^***	69.4 ± 3.2^***	82.9 ± 1.9^***		70.3 ± 2.5^***	61.9 ± 1.9^***
	Splashing	80.7 ± 2.2^***		73.5± 3.8^***	61.6 ± 3.2^***	–	79.6 ± 2.2^***		60.1 ± 2.0^***	_
Target spot powder in soil	Splashing						81.5 ± 2.1^***		70.4 ± 2.1^***	60.3 ± 1.6^***
Stored cultures	Suspension spray	83.4 ± 2.2^***	82.7 ± 1.8^***	81.3 ± 2.0^***	80.9 ± 2.2^***	78.6 ± 2.0^***	82.5 ± 2.1^***	79.2 ± 1.2^***
Successive subcultures	I subculture spray						85.5 ± 2.6^***
	II subculture spray						85.6 ± 2.9^***
	III subculture spray						81.3 ± 2.2^***
	IV subculture spray						84.0 ± 2.7^***
	V subculture spray						81.7 ± 1.8^***
	VI subculture spray						79.3 ± 2.1^***

a RT = room temperature.

*** Significance level at p ≤ 0.05; Empty column indicates experiment not done.

Table 1 Tests for viability of target-spot tissues (leaf and petiole) stored at 5 °C and RT^a (by culturing on PDA media).

Storage period	Storage condition	Total no. of target spots cultured/plate		Average percentage of viability
		Leaf spots	Petiole spots	Leaf spots (%)	Petiole spots (%)
The day after inoculum collection	–	10	6	100 ± 0	100 ± 0.0
After 4 months	5 °C	10	6	93.4 ± 3.3	94.4 ± 5.5
	RT	10	6	86.7 ± 3.3	88.6 ± 5.5
After 8 months	5 °C	10	6	76.7 ± 8.8	77.7 ± 5.5
	RT	10	6	50.0 ± 5.7	55.5 ± 5.5
After 16 months	5 °C	10	6	63.4 ± 8.8	50.0 ± 9.5
	RT	10	6	0.0	0.0

a RT = room temperature.