title: Bioassay techniques to assess plant pathogenicity of Mycoplasma-like organisms (MLO).
abstract: A bioassay for mycoplasma-like organisms ( MLO ) plant yellows is proposed. The relation P=e(-)nM enables calculation of the average number (M) of infectious units (IU) injected per insect as a function of the proportion P on non-diseased plants and of the number n of vectors per plant. The injected volume was determined by injecting a radioactive solution, and the results can thus be expressed in IU/ml. A diagram is proposed which directly gives the concentration in IU/ml of the tested extract before its dilution. Male cicadellids were shown to respond much better to injection than females. We thus decided to inject males only. However, the susceptibility of both insect and plant is not total, and a certain under evaluation of the results cannot be avoided. These results, however, afford the best approach to knowledge of MLO .
mesh_terms: D001431:Bacteriological Techniques; D009174:Mycoplasma / Q000472:pathogenicity*; D010944:Plants / Q000382:microbiology*