Soybean rust is a serious disease causing crop losses in other parts of the world. It is spread mainly by wind and can be carried over long distances. Asian soybean rust, P. pachyrhizi, the more aggressive of specie, was first reported in Japan in 1903 and was kept in the Eastern Hemisphere until it was discovered in Hawaii in the mid-nineties.

CAUSE

  • A fungi: Phakopsora pachyrhizi

DISEASE SYMPTOMS

Symptoms begin on the lower leaves as small lesions that increase in size and change from gray to tan or reddish brown. Tan lesions, when mature, consist of small pustules surrounded by a slightly discolored deadened area with masses of tan spores on the lower leaf surface. Reddish brown lesions have a larger reddish brown deadened area, with a limited number of pustules and few visible spores on the lower leaf surface. Once pod set begins on soybean, infection can spread rapidly to the middle and upper leaves of the plant.

Information from the Extension Disaster Education Network

HOST RANGE

  • Soybean
  • Kudzu
  • Lupine
  • Common bean
  • Vetch
  • Clover
  • Cowpea, pea
  • Sweet clover
  • Medic

GEOGRAPHIC DISTRIBUTION

As of Jan. 13, 2006, found in the following states:

  • Florida
  • Georgia
  • Alabama
  • Mississippi
  • Louisiana
  • Texas
  • South Carolina
  • North Carolina

For more on geographic distribution, click here

SPREAD of the PATHOGEN and CONTROL OPTIONS

  • Spread by windborne spores
  • Controlled by fungicide application

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