Venezuela

Powdery scab situation

Potato are mainly cropped in the highlands, mostly at the Andes. Although powdery scab is found from 800 to > 3.000 meters above sea level, it is most abundant at 2000 or more. There are two rainy seasons, which correspond with two planting periods. The first one is heavy and runs from about April to August with climatic conditions more conducive for powdery scab, whereas the second (a light one) is from October to December. Most of the hectares are planted in the first season. Growers are not used to apply fungicides at planting or hilling time and the main cultivars used are susceptible (Granola and some Solanum tuberosum ssp andigena cultivars). Under those conditions and depending on the climate yield losses can go from 10 to 100%.
In Europe Granola is thought to be little susceptible to powdery scab. In Venezuela Granola usually gets more infected in the first season than in the second. Other cultivars (from S. tuberosum ssp andigena, for example; or Kennebec in lower lands) are more susceptible than Granola and they get infected in both seasons. The reason Granola shows certain level of susceptibility might be because the more severe disease pressure in the first season. However, this needs more research, because under controlled conditions, Granola has shown some sort of resistance also in Venezuela.

15 to 20 years ago, powdery scab used to be rather a curious disease, therefore little research was done before.

Research

Because of the concern of the growers, research started on control as well as on characterizing the pathogen populations.


Contact addresse:

Dorian Rodriguez
Postgrado de Agronomía
Carretera Via Redoma de Agua Viva
Frente a Urbanización Terepaima Cabudare
Estado Lara
Venezuela


e-mail:

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Last update: January 2025