Effect of SO₂ and/or O₃ on root-knot nematode morphometrics which parasitises green gram

All morphometric parameters (lengths of body, neck, stylet and median bulb and widths of body, neck, stylet knob and median bulb) of Meloidogyne incognita race 1 mature females, showed a significant increase in presence of Rhizobium leguminosarum. The above parameters decreased gradually with progressive increase in SO₂ and/or O₃ exposure levels, except body and neck lengths. Such disturbances to nematode morphometrics were comparatively less in presence of R. leguminosarum. Moreover, O₃ proved to be more effective in disturbing the different morphometric parameters compared to SO₂ of same level. The disturbances to morphometrics were found in the following progressive way: SO₂< O₃<SO₂ + O₃. Different SO₂ (0.1 to 0.3 ppm) and O₃ (0.1 to 0.3 ppm) crossed possible combinations were proved more reductive to nematode length and width (except body and neck lengths) than either of their individual treatments. However, the female morphometrics showed greater disturbance at higher than lower SO₂+O₃ combinations, with or without R. leguminosarum. Green gram plants to the 0.3+0.3 ppm SO₂ + O₃ showed maximum disturbance in the nematode morphometrics.