The viability of Meloidogyne incognita eggs released from egg masses of different ages using different concentrations of sodium hypochlorite

The proportion of eggs of Meloidogyne incognita which hatched following extraction from egg masses with sodium hypochlorite solution (NaOCl) was shown to be related to the proportion that were embryonated at the time of extraction. Following NaOCl extraction, young egg masses (4-5 weeks after inoculation), which contained proportionally fewer embryonated eggs, yielded proportionally fewer juveniles than did old egg-masses (8-9 weeks). Using eggs extracted with NaOCl as inoculum a similar difference was observed in the numbers of juveniles which invaded tomato roots. Differences between two experiments in the rate at which eggs were released by the same nominal concentration of NaOCl were subsequently attributed to differences in chlorine (Cl) content. A further experiment where the Cl content was assayed showed that the numbers of eggs extracted increased, but that their viability decreased, with increasing concentration and duration of exposure to NaOCl. Overall, NaOCl was most effective when used on older egg masses with a high proportion of embryonated eggs.