A Bacterial Disease of the Mango. Bacillus Mangiferae N.SP

SUMMARY A disease of mangoes, hitherto undescribed, has for the last few years been causing considerable loss to mango growers in the Union. So far as can be ascertained the disease is not known outside South Africa, and it occurs in this country in the neighbourhood of Barberton and Warmbaths, in the coast region of Natal and at Delagoa Bay. Dark angular spots are formed on the leaves which do not noticeably affect the general health of the tree, but serve as a source of infection for the fruit. On the latter the disease causes discoloured roughened areas and deep cracking; infected fruit is detached from the tree by the slightest air movement and falls rotting to the ground. Infection is carried by the wind, and by rain dripping from infected leaves. Very few insects are found on the mango foliage. Spraying experiments have been conducted which show that spraying with Bordeaux mixture, iron sulphide or Hycol is useless in checking the disease. The cause of the trouble is a flagellate bacillus Bacillus mangi‐ferae n. sp. It invades the parenchyma, wedging apart and killing the cells and causing gummosis; lignified tissues are not touched. The organism is described in detail and a resume is given of its salient characters.