Rodent control in Malaysia
Basic Characteristics of Rodents Mostly Small Mammal anything smaller than a cat. Rodere to gnaw (dentition sharpe-edged, sharpened & worned down, open rooted incisors- hard anterior enamel and exposed posterior dentine- continuous growth, thus constant gnawing.) Dental formula 1 0 0 3 1 0 1 3 1 0 1 3 1 0 1 3 Squirrel (Scuiridae); Rats (Muridae); Porcupines (Hystericidae) - Largest Mammal Order ~ 40% from approx 5700 species. (other rodents guinea pigs, Chinchillas, beaver, capybara (may weigh up to 65 kgs), prairie dogs, hamsters, gerbils, jerboas, muskrat, voles, mole rat, bandicoot, kangaroo rat etc)
Pest Ecological/Economic importance vectors (zoonoses) Seed dispersers Food for predators (prolificity) Food (protein) source Source of fur (fur farming) Pets Model organism (animal testing) Conservation
Common Rodent Pest Rattus argentiventer Ricefield rat Rattus tiomanicus Wood Rat Rattus rattus diardii Field Rat/House Rat
Rattus argentiventer Ricefield rat
Rattus tiomanicus Wood Rat
Rattus rattus diardii Field Rat/House Rat
History of rat control Large scale rat hunting in ricefield at turn of the 20 th century Breeding domestic cats in oil palms supplementing diet with milk Reliance on natural predators encouraged the presence of snakes Using rodenticides acute poisons and anticoagulants (with the advent of warfarin)
Rodenticides Problems of bait shyness Resistance towards rodenticides Hazards to non-target organisms (livestocks and wildlife) Increasing cost (surveys indicated that baiting cost may run from RM10 to RM64/ha/year in oil palm; average ~ RM24/ha/year
Alternative control Biological control natural predators (monitor lizards Varanus salvator; Common cobra Najah najah etc) Limited success, unreliable, unpredictable, cannot stop outbreaks Novel idea propagating the presence of barn owls Tyto alba in oil palm plantations
History of barn owl Vagrant species local population thought to have originated from Sumatra and Java Local species Tyto alba javanicus Earliest recorded sighting end of the 19 th century Fond of nesting in buildings; thus numbers are limited by nesting sites G.M Lenton (1978) experimented the idea of setting artificial nest boxes in oil palm
Barn Owl
Barn owl nest box
Early success Barn owl readily occupy boxes Rate of nest box occupancy reached ~ 80% during peak breeding season. Baiting needs drop by 40% in some instance Provision of nest boxes and high density of rats boosted local populations Sustainable rat control program numbers naturally regulated by the presence of rats and rat breeding cycle
Control of rats in oil palm using barn owls Baiting requirement in oil palm Bait replacement 200 150 100 50 0 m 83 a 83 m 84 a 84 m 85 a 85 m 86 a 86 m 87 a 87 m 88 Date of baiting session
Introduction in ricefield The success in oil palm prompted similar efforts in ricefield areas. Pilot projects were initiated in the state of Selangor and Perak Again high occupancy rates were recorded in the first year of its implementation (1988) Number of baiting rounds were reduced from 16 to only twice a year
Effectiveness: bait supply Quantity of rat baits supplied by the Agric. Dept (1985-96) Quantity of rat bait (tons) 50 40 30 20 10 0 85 86 87 88 89 90 91 92 93 94 95 96 Year
Reduction in baiting rounds Provision of nest boxes Year 88 89 90 91 92 93 94 95 No. baiting rounds/yr 16 16 8 4 4 2 2 2 Baiting rounds in pilot project areas (Source: Dept of Agric)
Features of the barn owl Readily occupy nest boxes High consumption/predation rate one estimate put the number of rats predated upon at 3,000 per pair per breeding season. High preference for rat prey ~ 99% of prey composition reflects prey availability Great tolerance towards first generation rodenticides More economical than sole reliance on rodenticide cost largely being the construction of nest boxes (The cost of constructing wooden nest box ~ RM 691; fibreglass RM 497) Reduction in rat control cost ranged from just RM2/ha/year to ~ RM20/ha/year
Rat damage to rice (1988-95) Rat damage (% crop loss) 10 8 6 4 2 0 2 (88) Provision of nest boxes 1 (89) 2 (89) 1 (90) 2 (90) 1 (91) 2 (91) 1 (92) 2 (92) 1 (93) 2 (93) Planting season 1 (94) 1 (94) 1 (95) 2 (95) Perak Selangor
Barn owl monthly nest box occupancy rates at Sawah sempadan 80 70 60 50 40 30 20 10 0 booting harvesting booting harvesting S O N D J F M A M J J A 1993 1994 1995 1996 1997
Future prospect The hazards of secondary poisoning from second generation rodenticides (brodifacoum, bromadiolone) Exposed to secondary poisoning from a single prey Resistance towards first generation rodenticide has prompted plantations to switch to second generation rodenticides Combination of baiting with second generation rodenticide and natural breeding of barn owl will spell disaster of the latter
Control Method % Estates 70 60 50 40 30 20 10 0 17.9 21.4 60.7 Baiting only Barn owl only Baiting & Barn owl
Types of rodenticides % Estates 100 80 60 40 20 0 68 16 8 Warfarin Chlorophacinone Bromadiolone Brodifacoum 8
Combining baiting with Barn owl Estate nos. 10 9 8 7 6 5 4 3 2 1 0 10 1st gen & barn owl 7 1st gen. Only 3 2nd gen & barn owl 4 2nd gen. Only
CONTROL METHOD % Estates 60 50 40 30 20 10 0 Baiting only Barn owl only Baiting & Barn owl 2000 2001
COMBAINING BAITING AND BARN OWL No. estates 14 12 10 8 6 4 2 0 2000 2001 1st gen + Barn owl 1st gen only 2nd gen + Barn owl 2nd gen only
The prospect of using Sarcosystis singaporiensis Reticulated python Phyton reticulatus is a common predator in oil palm. Isolation and culturing of local strains Formulation of local strains of Sarcosystis as potential biorodenticide Barn owl Suggestion for isolation of Sarcosystis sp. From feeding pellets of oil palm?
Rat control in:- Prospect of Sarcosystis singaporiensis Oil palm plantation Paddy fields Cocoa plantation Poultry farms Urban rat control
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