ABSTRACT
Solanum whitefly, Aleurothrixus trachoides (Back). (Hemiptera: Aleyrodidae) was considered as a non-virusvector by European and Mediterranean Plant Protection Organization (EPPO) reports. However, in the presentstudy it was found to transmit Duranta leaf curl virus (DLCV) to tomato, bell pepper and potato. A. trachoidesinfested field samples of Duranta sp (100%) and tomato (20%) tested positive for begomovirus by PCR usingbegomovirus degenerate primers and primers specific to Tomato leaf curl New Delhi virus showing ampliconof 520 bp and 2.7 Kb respectively. The DNA samples of A. trachoides collected from virus positive durantaand tomato plants also tested positive for the virus. Virulent whiteflies from duranta could successfully transmitDLCV to bell pepper (26%) and tomato (13%) plants as confirmed by Rolling Circle Amplification. The rate ofvirus transmission by A. trachoides from DLCV inoculated tomato to bell pepper and tomato to potato was100% and tomato to tomato was 80%. The results suggest whitefly A. trachoides as the vector for DLCV and tothe best of our knowledge, this is the first report for A. trachoides as vector of begomovirus. These findingssuggest need for reconsideration of A. trachoides as a virus-vector. This will have great impact on solanaceousvegetable cultivation in India and other parts of the world.
ABSTRACT
Consumption of fresh vegetables is very common in Nigeria. One of the methods of increasing the availability of vegetables all year round is drying. There is need to determine the microbial quality/safety of the dehydrated vegetables in order to determine the risk of food borne diseases. The microorganisms associated with three dehydrated vegetables (bitter leaf, bell pepper and okra) were isolated, identified and enumerated. The moisture contents of the vegetables were determined and the effects of varying temperature levels on growth of microbial isolates recovered from the samples were studied. A total of nine bacteria, namely: Staphylococcus aureus, Acinetobacter iwoffi, Corynebacterium sp., Bacillus pumilus, Micrococcus sp., Pseudomonas aeruginosa, Flavobacterium sp., Bacillus sp., Micrococcus kristianae and eleven fungi: Aspergillus niger, A. flavus, Aspergillus spp., Penicillium spp., Cladosporium sp., Fusarium spp. were isolated. The mean for total colony forming units (cfu/g) for bacteria were 2.1x107cfu/g, 6.1x105cfu/g, 2.2x106 cfu/g for bell pepper, bitter leaf and okra, respectively while the mean for total colony forming unit (cfu/g) for fungi were highest (1.3 x 106cfu/g) in bell pepper while bitter leaf recorded the least (7 x 103cfu/g) mean for total colony unit for fungi. The mean for percentage (%) moisture content ranged between 16.6-25.8%.The optimum growth was recorded for all the bacteria and fungi at 37ºC and 30ºC; nearly all the isolates had their growth retarded at 45ºC. The recovery of several harmful microorganisms in this study suggest the need for proper handling of vegetables during processing and storage to minimize microbial contamination in order to protect consumers’ health.