Abstract:
Surveys were conducted to assess the incidence of seed borne pathogens on
fingermillet (Eleusine coracana (L.) Gaetrn) and sunflower (Helianthus annus L.) in
seeds produced by farmers in Morogoro Rural, Kilosa districts (Morogoro Region),
Kondoa, Dodoma Rural districts (Dodoma Region), and Njombe and Iringa Rural
districts (Iringa Region), in Tanzania. A total of 72 seed samples were collected and
taken to the laboratory for assay of seed-borne pathogens. The blotter method was
used to detect fungal pathogens and identification was done based on colony
morphology, characteristics of fruiting bodies and spores observed under the stereo
and compound microscopes. Seed-borne bacterial pathogens were detected using the
direct plating method and identified based on pigmentation, biochemical tests, carbon
source utilization, and hypersensitive reaction (HR), as well as pathogenicity tests.
Three fungal pathogens (Pyricularia grisea, Bipolaris setariae and B. nodulosa) were
detected in fingermillet seed samples. The level of seed infection ranged from 10 to
50%. Pyricularia grisea was more prevalent in most fingermillet seed samples tested.
Only two fungal pathogens (Altenaria altenata and Verticillium albo-artum) were
detected on most of the sunflower seed samples tested. Bacterial pathogens detected
on fingermillet seed included Pseudomonas eleusines, Xanthomonas campestris pv
corocanae, Pseudomonas syringae pv syringae and P. andropogonis. The pathogens
Erwinia caratovora subsp caratovora, P. marginalis pv marginalis, P. syringae pv
tagetis, P. syringae pv helianthi and P. syringae pv aptata were detected on sunflower
seed samples. Pseudomonas andropogonis (causing bacterial stripe), was detected on
fingermillet in samples collected from Ilonga Kilosa, Zanka Dodoma Rural district,
Kinonko and Mikese Market in Morogoro Rural district. The result of this study hasiii
also established very important information on the occurrence of fingermillet blast (P.
grisea) and bacterial stripe (P. andropogonis) across the surveyed regions. This is the
first report of P. andropogonis on fingermillet in Tanzania.
