Abstract:
Parkinsonia aculeata and Prosopis juliflora are two major woody weeds widely
distributed in Hambantota district. Control of these two woody weeds was one of
the major issues of concern in agriculture in Hambantota district. The pods of these
two weed hosts were found to the attacked by a pod boring insect pest. The purpose
of the present research was to identify the pod boring insect pest, study its biology,
taxonomy, distribution and abundance on two woody weeds, P. aculeata and P.
juliflora.
Eight experimental sites were selected and hundred pods were collected from each
woody plant. In each sample, pods were categorized into several groups and daily
emergence of insects was recorded. Taking into consideration of the experimental
design the data collected were analyzed using t-test.
Araecerus fasciculatus was found in all sixteen experimental sites but no
significant variations were recorded. Significant variation between seasons was
recorded in P. aculeata woody weeds but not on P. juliflora woody weed.
Abundance of pod boring insects has shown a close relationship with the monthly
rainfall in the Hambantota district. However there were instances, where this
relationship was not prevailing. Also pest abundance change according to the type
of weeds.
Both woody weeds are considered as reservoir hosts of A. fasciculatus. It becomes
a major problem for Agriculture in the Hambantota district. However the increased
infestation levels of A. fasciculatus on two woody weeds is encouraging for further
developments in weed control programs as this borer reduces the production of
viable seeds. Encouragements of the production of the borer can be used in
combination with other control measures such as weedicides etc..
