Ka. Eltarabily et al., ASSOCIATION OF PYTHIUM-COLORATUM AND PYTHIUM-SULCATUM WITH CAVITY SPOT DISEASE OF CARROTS IN WESTERN-AUSTRALIA, Plant Pathology, 45(4), 1996, pp. 727-735
All 170 Pythium isolates from carrot cavity spot lesions from a field
in Western Australia were found to belong to either P. coloratum or P.
sulcatum. All isolates of P. coloratum produced large, brownish-black
, water-soaked and depressed lesions on mature carrots inoculated with
agar plugs colonized by the pathogen. In comparison, only a few isola
tes of P. sulcatum produced lesions and these were small. In glasshous
e trials, P. coloratum produced substantial and numerous lesions at an
inoculum density of 0.5% (weight of millet seed-based inoculum/weight
of soil), whilst P. sulcatum produced few and small lesions at inocul
um densities of 0.8 and 1% and none at 0.5%. This is the first record
of P. coloratum as a causal agent of cavity spot of carrots.