| a large-scale snail control trial with trifenmorph in the gezira irrigation scheme, sudan. | a large-scale field trial was carried out during december 1973 to assess the effect of trifenmorph on bulinus truncatus and biomphalaria pfeifferi in 379 000 feddans ( approximately 159 000 ha) of the gezira irrigation system in the sudan. the commercial formulation used (frescon) is an emulsifiable concentrate containing 16.5% trifenmorph. five dispensers were used to add the commercial product to the water continuously for 7.5 days; 18 121 litres were used to treat 28.4 million m(3) of water. ... | 1976 | 1088406 |
| transmission of schistosoma haematobium in north gezira, sudan. | during this 14-month study, 128 765 bulinus truncatus snails were collected from canals located near four villages in the northern part of the gezira irrigated area, and were examined for patent trematode infections, by exposure to light. in all, 903 shedded cercariae, of which 424 were identified as s. haematobium, and one village, bashagra, was the source of 80% of these s. haematobium infections. the highest density of snails occurred from march to may and the peak of snail infections occurre ... | 1985 | 4032531 |
| snails and aquatic vegetation in gezira irrigation canals. | all 38 minor canals in a limited area of the gezira irrigated area were surveyed four times over a 2-year period to determine the aquatic and semi-aquatic vegetation types found and their distribution. a more detailed 2-year study of the correlation between snail density and aquatic vegetation was carried out in 18 of these canals. a total of 22 different species of weed were recorded, with floating and submerged weeds being more widespread and dense in the clear, slow-moving water at the end of ... | 1985 | 4032532 |