Peanut mottle virus in East Africa.
Groundnut mottle virus was identified on the basis of particle morphology, serology, host range and reaction, transmission and physical properties; it is a common pathogen of groundnut and soybean in E. Africa. Adequate virus concs. for serological tests were obtained in cowpea cultured at 27 deg but not at 23 deg C. The virus was purified using 0.5 M Na citrate buffer containing 1% mercapto-ethanol; an antiserum made against such preparations had a homologous titre of 1/8192. Isolates from groundnut and soybean in N., N.E., N.W. and S. districts of Uganda, N.W. Tanzania and W. and E. (coastal) districts of Kenya were serologically similar, and varied only slightly in symptoms induced in certain cvs., while a related but distinct str. was isolated from Voandzeia subterranea. The virus was not related serologically to any of 10 viruses in the potato virus Y group. In glasshouse experiments 20% seed transmission was obtained in groundnut. It was transmitted by Aphis craccivora in a nonpersistent manner. All 21 cvs. and breeding lines of soybean tested were highly susceptible. The prevalence of the virus and the reduction in yield caused in groundnut indicated its economic importance, and groundnut and soybean breeding programmes should include routine susceptibility tests.<new para>ADDITIONAL ABSTRACT:<new para>A common and widespread virus of groundnut and soy bean in East Africa (Uganda, Kenya and Tanzania) was identified as peanut mottle virus (PnMV), on the basis of particle morphology, serology, host range and reaction, transmission and physical properties. The virus was transmitted through the seed, and in the non-persistent manner, by Aphis craccivora Koch.