June 2, 2004
From: RTE news, 28 May 2004 [edited]

Potato blight reported in Cork and Kerry

The 1st outbreaks of potato blight in Ireland in 2004 have been reported on farms in Kerry and Cork.

According to the Teagasc blight recording system, blight hit Kerry on 28 Apr 2004 and spread to Cork on 18 May 2004.

The recording system tracks the initial outbreak of the disease, in the different potato growing areas, with the aim of helping growers to implement effective blight-control programs.

Dr. Leslie Dowley, potato blight research specialist with Teagasc, said that the average date for outbreak of blight, for main crop potatoes, is usually in the latter half of July. However, for early crops in the south of the country, disease outbreak can be much earlier.

Once blight has made its initial appearance, the further development of an epidemic is dependent on the control program, potato variety, growth stage, and the prevailing weather conditions.

All potato growing areas are being monitored by the potato inspectors of the Department of Agriculture and Food as well as the specialist potato advisers in Teagasc.

[Potato late blight, caused by _Phythophthora infestans_, is the most important disease affecting the potato crop in Ireland, and, also, attracts the greatest research input. Problems facing plant pathologists include fungicide-resistance, mating-type, aggressiveness, epidemiology, and the development of methods for the reduction of fungicide use.

According to Dowley, the 1st reports of late blight in 2004 indicate that outbreaks are occurring a little earlier than usual. Normally, the 1st outbreaks are recorded in the south coastal areas, followed by outbreaks on the east and north coasts, and, finally, by outbreaks in the midlands.

Of particular interest to plant pathologists is the recent publication -- by May and Ristaino at North Carolina State
University, Raleigh -- implicating the la strain/haplotype of _Phytophthora infestans_ as the causal pathogen of late blight disease in the 1840s. Moreover, it appears that this strain probably has its origin in the Andes Mountains in South America (as opposed to the prevailing theory that the pathogen originated in Mexico).

I thank Leslie Dowley for his comments on this outbreak.

Reference:

Kimberley Jane May and Jean Beagle Ristaino <Jean_Ristaino@ncsu.edu>, 2004. Identity of the mtDNA haplotype(s) of _Phytophthora infestans_ in historical specimens from the Irish Potato Famine. Mycological Research (2004), 108:471-479 Cambridge University Press.

<http://www.innovations-report.de/html/berichte/agrar_forstwissenschaften/bericht-27183.html>
<http://www.planteinfo.dk/kartoffelinfo/negfry/english/default.asp>
  - Mod.DH]