Source
of information is the APSnet
Images provided by USDA scientists.
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Symptoms
The most
common symptoms
of soybean rust on cultivated soybean are 2 to 5 mm2 tan to
dark brown polygonal lesions. Within each of the lesions is
one to many erumpent, globose uredinia.
Early
infection by Phakopsora pachyrhizi on a susceptible
soybean
Phakopsora
pachyrhizi: susceptible (TAN) lesions.
Phakopsora
pachyrhizi: red brown (RB type) lesion with some sporulation.
Phakopsora
pachyrhizi: red brown (RB type) lesion with some sporulation.
Phakopsora
pachyrhizi: RB lesion with circular ostiole and spores.
Phakopsora
pachyrhizi RB lesion with no sporulation.
Urediniospores
are released through the circular ostiole. Lesions are found
on petioles, pods, and stems but are most abundant on leaves
(Fig. 4). As rust severity increases, premature defoliation
and early maturation of plants is common.
Soybean
rust pustules caused by Phakopsora pachyrhizi on the
upper side of a soybean leaf.
Soybean
rust pustules caused by Phakopsora pachyrhizi on a
soybean cotyledon.
Soybean
rust pustules caused by Phakopsora pachyrhizi on petioles.
Soybean
rust pustules caused by Phakopsora pachyrhizi on stems.
Soybean
rust pustules caused by Phakopsora pachyrhizi on the
under side of a soybean leaf.
.
Acknowledgement
and Disclaimer
Photo credits: USDA-Agricultural Research Service except where
noted from collaborators in the figure legend.
Names are necessary to report factually on available data;
however, the USDA neither guarantees nor warrants the standard
of the product, and the use of the name by the USDA implies
no approval of the product to the exclusion of others that
may also be suitable
