Incidence, Distribution and Characteristics of Major Tomato Leaf ...

Incidence, distribution and characteristics of major tomato leaf curl and mosaic virus diseases
and the positive sample also turned yellow on the same plate, while the negative sample
and blank wells remained clear.
3.2.3.2 Chilli Veinal Mottle Virus Host Range
Weed samples and other crops showing veinal mottle/mosaic symptoms were collected
from within and around tomato fields. These samples belonged to species Ageratum
conyzoides, Aspilia africana, Bidens pilosa, Colocasia esculenta, Commelina
benghalensis, Crassocephalum spp., Galinsoga parviflora, Lantana camara, Manihot
esculenta, Ocimum basilicum, Phaseolus vulgaris, Sesbania sesban, Solanum nigrum,
and Sonchus oleraceus.
In the laboratory, samples were sliced into small pieces and wrapped in labelled filter
paper over anhydrous calcium chloride. After 9 months, dried weed samples were tested
for the presence of ChiVMV using DAS-ELISA (Clarks and Adams, 1977). A sample
was considered positive if both replicates turned obviously yellow in microtiter plate
wells, and the positive sample also turned yellow on the same plate, while the negative
sample and blank wells remained clear.
3.3 Results
In this section, results of serological tests conducted to ascertain mottling and mosaic
symptoms observed in tomato fields and causal viruses, which are also found in countries
neighbouring Uganda, are presented. Results of molecular tests conducted for those
viruses that could not be tested using serological techniques are also presented. Lastly,
alternative host plants found in the tomato agro-ecosystem and with susceptibility to
tomato viruses are reported upon.
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