الفهرس يوجد فقط 14 صفحة متاحة للعرض العام
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المستخلص
The development of an effective strategy for implementation of rodent pest management programs in cultivated and newly reclaimed agro ecosystems in Egypt is of great importance.
So, the present work was carried out on rodents during the period from June 2004 till May 2006. Five areas in Assiut Governorate were chosen to determine the species composition of rodents, the population density by several methods, colour and food preference in rodent baits and control of rodents. Results can be summarized as follows:
1- Species composition of rodents in cultivated and reclaimed lands:
Species composition of rodents in Faculty and El-Ghorieb Farms revealed the presence of three species of rats included the Nile grass rat, Arvicanthis niloticus (Desm.), the grey bellied rat, Rattus rattus alexandrinus (Linn.) and the white bellied rat, Rattus rattus frugivorus (Linn.). The R .r. alexandrinus recorded an average dominant percentage (24.26 % and 7.84%) in Faculty and El-Ghorieb Farms, respectively. However, the average dominant% for R.r.frugivorus was (14.35% and 28.30%) and for A. niloticus (11.39% and 13.85%) in Faculty and El-Ghorieb Farms, respectively.
The Norway rat, Rattus norvegicus was the only rodent encountered in the River Nile Bank. Also, survey of rodents in Arab-El-Awamer and a newly reclaimed area revealed the presence of four species of rats included A. niloticus, R.r.alexandrinus, the house mouse, Mus musculus and lesser gerbia, Gerbillus gerbillus. The dominant percentage values of R .r. alexandrinus was (63.27% and 18.92%), A. niloticus (24.49% and 67.57%), M. musculus (12.24% and 0.0) and G. gerbillus (0.0 and 13.51%) in Arab El-Awamer and the newly reclaimed area, respectively. The presence of Mus musculus may be due to the establishment of building or the husbandry beside the study areas.
2- Determination of the population density of rodents by using different methods:
2-1-Trapping method:
Generally, the number of rodents trapped recorded from the Faculty and El-Ghorieb Farms from June 2005 till May 2006 was decreased (385 individuals) compared with this number which trapped from the same area (497 individuals) through June 2004 till May 2005. The decreased of the density may be due to the trapping during the last year or due to the decreased of the food in this area through this year.
In the Faculty and El-Ghorieb Farms the highest seasonal trap index values was recorded in spring while, the lowest values in winter. In general, males outnumbered females.
2-2- Feces method:
In poultry farm, the highest population was observed during in November (10.86%). The lowest population was during January (6.46%) and March (7.57%).
In Arab El-Awamer the highest population was recorded in August (10.18%) and July (10.02%). The lowest was (6.57%) in June and September (6.73%). This may be due to the marked activity of rodents and food abundance in these months.
2-3-Active burrows method:
In newly reclaimed area, the highest population density of rodents determined by using active burrows method was recorded in autumn (39.59%). The lowest was (8.35%) in spring. This may be due to increase in active burrow after harvesting the crops.
2-4- Food consumption method:
In River Nile bank, the highest amount of food consumed was recorded during the autumn season (5700gm). The lowest was observed during spring (3200gm).This may be due to the increase of natural food during spring.
3-Colours preference of rodent bait
3-1- Colour preference under field conditions:
Six colored baits were tested. The results indicated that rodents preferred the green, grey and red baits rather than the yellow, brown and blue baits. We can say that the rodent species preferred the coloured baits in the traps especially the green colour.
3-2-Colour preference under laboratory conditions:
In this study six colored baits were tested. Results revealed that rodents preferred the grey, green and red baits more than the yellow, blue and brown baits. This finding may be useful in preparation of rodent baits for rodent control.
4- Food preference of rodents baits:
Four rodent baits were used included cucumber, tomato, bread and potato. Results indicated that cucumber and tomato baits attracted the highest number of rodent species followed by the other baits. This may be useful to the preparation of rodent baits in rodent control, or to capture rodent for use as an experimental animal. Baits preference tests should be done periodically to find out the proper bait for rodenticide formulation and to overcome the shyness of rodent baits.
5- Rodents control:
5-1-Mechanical control
The highest reduction of rodent active burrows in the untreated area was recorded in spring (52.21%), while the lowest was (20.63%) in autumn. In treated area high reduction of rodent active burrows was recorded in spring (71.43%) the lowest was (49.20%) in autumn.
Mechanical control of rodents by using the destruction of rodent active burrows achieved great success in rodent control under field conditions without environmental pollution and not costly.
5-2-Biological control
Cats (Felis chaus nilotica) as Naturally Occurring Biological Control Agent (NOBCA) were used in grain storages. The percentage of reduction during the presence was recorded as 90.91%. After 6 months the reduction % of the predator was 33.33%.
The decreased in the efficiency of cats in reduction rodents population after six or seven months may be due to the predation prey efficiency of cats. Also, the feeding habits of the cats to prey upon variety of preys and switch their attention for one to other prey species according to the relative abundance. This switching behavior has two important effects, it allows the predator to survive when a particular prey species is low in numbers and it helps to keep it in check.
5-3-Chemical control
Two rodenticides zinc phosphide 3% and supercaid (bromadilone 0.005%) were tested against rodents by using single feeding under field conditions.
Generally speaking, the recorded results proved that the total average of zinc phosphide 3% was effective against the rodents with a reduction percentage (56.35% and 73.13%), while in treated area with supercaid was (34.21% and 57.13%).In the Faculty Farm and Arab El-Awamer, respectively.
The reduction in the population density of rodents determined by rodent feces proved that zinc phosphide 3% concentration gave efficiency higher than supercaid against rodents.
In the River Nile bank area zinc phosphide 3% during (November) during 2004 was used in the first area and the second area was treated with zinc phosphide 3% in (January) and supercaid 0.005% in (July) .The reduction in food consumption was recorded in the first area during November 48.87% and 37.44% in the second area. However, used zinc phosphide 3 % in the second area (January, 2005) showed that increased reduction in amount food consumption in the two area were recorded (52.94% and 55.35% respectively). Also, results proved an increase in reduction of food consumption of rodent after using supercaid (July) in the second area was 66.52% and 62.33% in the first and second areas, respectively.
In conclusion, the recommended procedure for rodent control is applying zinc phosphide followed by anticoagulants twice annually seems to be satisfactory being applied within areas holding different habitats such as farms, buildings, open areas. However, it is rather important to give all possible attention to environmental sanitation. At the same time, type of applied anticoagulant should be changed upon appearance signs of resistance of rodents under control to such product. .