Maize bushy stunt phytoplasma in Brazil

Abstract

The maize bushy stunt phytoplasma (MBS) presence in maize crop in Brazil is reported since 1971. The MBS and the corn stunt spiroplasma (CSS) are both transmitted by the Dalbulus maidis leafhopper, their only insect vector in Brazil. This leafhopper and both mollicutes survive only in maize. These pathogens are always present in maize crop, at variable levels of incidence, causing losses in grain yield. Occasionally, outbreaks have been reported. Although they are difficult to be distinguished by symptoms, both pathogens can be identified by molecular analyses. There are evidences that, in the field, the MBS incidence can be higher than the CCS incidence or vice versa. The temperature can affect MBS acquisition and transmission. The D. maidis leafhopper migrates to large distances transporting MBS. The increasing importance of MBS disease can be due to changes in the scenery of the maize crop in Brazil since the 1970s, such as more than one maize crop season. Investigation about control methods is still lacking.