MICOLOGIA 614 Acalypha reptans a new host of Amphobotrys ricini

Tropical Plant Pathology 38 (Suplemento), agosto 2012
45º Congresso Brasileiro de Fitopatologia - Manaus, AM
Copyright the Brazilian Phytopathological Society htpp://www.sbfito.com
MICOLOGIA
614
Acalypha reptans a new host of Amphobotrys ricini.
(Acalypha reptans um novo hospedeiro de Amphobotrys ricini.)
Dantas, F.V.1, Nascimento, J.F.2, Soares, D.J.3
1
Discente Mestrado em Ciências Agrárias, UEPB, 2Técnica de Laboratório, 3Pesquisador,
Embrapa Algodão. E-mail: [email protected]
Amphobotrys ricini is regarded a major pathogen of castor due its highly epidemic potential. It
is widely known that the fungus is able to infect several euphorbiaceous hosts through the
world. During field surveys in the states of Rio Grande do Sul and Minas Gerais plants of
Acalypha reptans were found showing inflorescence blight with a powdery grey mass. Samples
were collected and dried in a plant press and later examined under a stereomicroscope. In the
microscope slides prepared from the diseased samples a fungus morphologically identical to A.
ricini was consistently found. The fungus was then isolated in pure culture to perform
pathogenicity tests. Inoculation was made spraying a spore suspension with 105 spores.ml-1 on
healthy plants of A. reptans and Ricinus communis. After inoculation the plants were maintained
a dew chamber for 48 hours. Symptoms of the disease appeared on both plants between 3 to 8
days after inoculation. This fungus already was recorded on the genus Acalypha, however this is
the first report of natural infection of this fungus on A. reptans worldwide. This study proves
that A. ricini has a wider host range than previously supposed and that probably the fungus is
able to persist through the year on ornamental or weed hosts.
Apoio: CNPq, Petrobrás, Capes.