Presence of phytoplasma infections in tomato plants in Mauritius.

Phytoplasmas were detected and identified in some tomato cultivation areas in Mauritius. Symptoms most frequently observed were abnormal shoot proliferation, stunting, reduced leaf and fruit size and shortened internodes. In field-grown tomatoes the incidence of abnormalities rarely exceeded 10%, but under hydroponics up to 100% incidence has been recorded. Two different phytoplasmas were identified by PCR/RFLP analyses. Field-grown tomatoes were infected with a phytoplasma belonging to ribosomal subgroup 16SrI-C and the hydroponically-grown tomatoes were infected with a phytoplasma belonging to ribosomal group 16SrV. Further studies need to be done in order to determine their occurrence, incidence, characterization, host range and mode of transmission, so that eventually the most effective method to control phytoplasma diseases will be determined

Detection of phytoplasma infection in okra in Mauritius

Using PCR and RFLP techniques, 16SrXII and 16SrV phytoplasma groups were identified from okra leaf samples originating from Mauritius. The most frequent symptoms observed on okra plants were leaf yellowing, leaf distortions, curling and plant stunting. The phytoplasma infection was widely distributed across the island and a high incidence of 75 to 100% was recorded at inspected sites. This is a first report of the presence of phytoplasmas in okra in Mauritius

Phytoplasma and virus diseases on tomato in Mauritius

An island wide survey carried over 18 months across 79 tomato (Lycopersicum esculentum L.) plantations in 30 localities on 12 varieties revealed that symptoms related to phytoplasma-associated diseases are widespread in this species in Mauritius. Typical witches, broom and stunting and/or yellowing were observed in 74.6 % of fields visited. Phytoplasmas belonging to three groups: stolbur (16SrXII), aster yellows (16SrI) and elm yellows (16SrV) were identified in tomato leaf and fruit samples by nested-PCR assays followed by RFLP and/or sequencing analyses. Mixed phytoplasma and virus infections (PVY, TYLCV) were detected in 28.8 % of symptomatic sample tested. Survey results indicate a widespread distribution of all identified phytoplasmas across local tomato plantations (pathogens were detected in 8 out of 9 districts) irrespective of the variety grown. Use of insect-proof nets for seedling production, avoid re-planting a new tomato crop in the vicinity of phytoplasma infected ones and uprooting of symptomatic plants are the recommended measures to reduce the pathogen dissemination and resulted to be effective in reducing the pathogen presence in the Country