The structure of the vulva cone of the lemon-shaped cysts of species of Heterodera is of taxonomic value. In H. avenae (=H. major) the transparent lip tops of the cone are narrow and have a very short touching line forming together the shape of the figure 8. The vulvar split is extremely short and this probably prevents the deposition of eggs in a gelatinous egg-sac which is a normal feature in other lemon-shaped species. These characters can be usefully used to differentiate H. avenae in mixed populations. In H. schachtii the transparent patches on the lip tops are smaller than in H, trifolii and the average length of the patches is 32.1 micro . In H. trfolii it is 45.6 micro According to the statistics presented these two species can be distinguished accordingly as the average length of the patches in five specimens of a popula tion is below or above 38.7 micro .
|Journal||Tijdschrift over plantenziekten|
|Publication status||Published - 1954|
- cysts (developmental stages)
- plant parasitic nematodes