Phytoparasitica (2002) 30 (3) - Control of Alternaria brown ...

A. Sadowsky, E. Yogev, Y. Auerbach and E. Shneor (2002)
Control of Alternaria brown spot (Alternaria alternata pv. citri) by potassium phosphate and potassium phosphite
Phytoparasitica 30 (3)
The 23rd Congress of the Israeli Phytopathological Society - February 11-12, 2002
Abstract: In an experiment conducted in the spring and autumn of 2001, two compounds which are known as acquired resistance inducers, Peak ® (KH₂PO₄) and Canon ® (K₂HPO₃ ), were tested for their ability to control Alternaria alternata pv. citri in 'Nova' tangelo. In August 2001 a significant difference was found among the four treatments tested in the percentage of fruit in class A, suitable for packing (less than five small spots of Alternaria per fruit). In the untreated control only 60% of the fruits were of class A. In the commercial chemical recommendation (five sprays, one every 2 weeks), 90% were class A. In the Canon treatment (four sprays, one every 4–5 weeks), 88% were class A. The Peak treatment did not differ from the control, with only 70% class A. The results at the end of autumn were similar, with only 50% class A fruits in the control and 58% in the Peak, which were significantly lower than 85% class A in the commercial and 86% in the Canon treatment. The encouraging results from the spring experiment led to three additional experiments conducted in the autumn of 2001, on 'Yanov' (Nova), 'Murcott' and 'Minneola' with only three treatments: untreated control, commercial recommendation (three sprays with dithiocarbamate, one every 4 weeks) and Canon (three sprays, one every 4 weeks). In this experiment the percentage of class A fruits in untreated control was significantly lower than in the commercial and Canon treatments: respectively, 53% in contrast to 77% and 83% in Yanov; 38% in contrast to 74% and 77% in Murcott; and 43% in contrast to 93% and 84% in Minneola. From these results it is suggested that Canon has a fungicidal effect on A. alternata pv. citri. The mode of action is not fully known.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)

Research topic(s) for pests/diseases/weeds:
control - general

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Alternaria alternata	Citrus (genus)