New, dangerous potato blight found in Estonia

Date:11-25-2010

Eve Runno-Paursons dissertation examined the Estonian population of the disease-causing agent, a water mold, and found that rather than a less dangerous historical form spread by wind and rain, the organism was reproducing sexually.

The blight, which caused the Irish potato famine 150 years ago and is still a costly, thorny problem for agronomists, has been striking fields a month earlier in recent years and showing fungicide resistance.
 
It also underwent a sea change in its reproductive biology during this period, from a largely wind and rain-borne problem to having the capacity for sexual reproduction.
 
Genetic fingerprinting showed that the Estonian population was unique and diverse, with most of the local genotypes not found elsewhere.
 
Even so, the Estonian population was similar in some respects to Russian and Nordic populations, leading to the conclusion that genetic transfer is fairly strong. Thats despite the fact that Estonian producers grow most of their seed potatoes themselves, with only 5 percent imported from the Netherlands.
 
The mold does not remain active forever, and the dissertation pointed up the importance of crop cycles with a four-year fallow period.