Overview of methods of management

During the IPM course this session begins with an overview of a range of control actions and then asks participants in the course to share their knowledge of actions of rodent management in their countries and regions.

Overview of methods of management:

• various snare and live-traps, usually made of bamboo, that choke a rat or break its back

• bamboo tubes -  simply offer cover for rats and either they get stuck or they are caught alive and emptied into a bag.

• digging of burrows to kill rats in situ; occasionally dogs are used to locate burrows or to help hunt rats flushed from burrows.

• rat drives or battues – where rats are driven from cover and herded towards nets.

• stalking at night with a kerosene light and a net at the end of a long handle – in Co Dung village of Hai Duong province in Vietnam, farmers apply this method from 1900-2200 hrs at specific times of the year.

• electrocution – electrical wire is strung the length of a rice crop about 10-50 mm above a flooded paddy, wet rats that make contact with the wire are quickly killed. As indicated below, this method presents an unacceptably high risk to human health.

• physical barriers – these usually consist of plastic or metal sheeting and are placed around or along the borders of crops or around areas where grain is stored.

• physical barriers plus traps – live-multiple-capture traps are inserted intermittently at the base of a physical barrier. The traps are placed against small holes in the barrier. Rats enter the traps, attracted to the developing crop or stored food that is on the other side of the barrier (see section 1 for details).

• metal rat guards – sheets of metal are wrapped around the trunk of a tree, higher than 1 m from the ground, to prevent rodents from climbing trees to access fruits. The design of the guards depends on the climbing habits of the rodent species, some are flat against the tree, whilst others are conical or circular metal sleeves, flush with the trunk of the tree but projecting outwards at, or less than, 90° from the trunk.

• scaring devices – white cloth or plastic is attached to a bamboo pole approximately 1.2 to 1.5 m high. The white material flapping in the wind supposedly mimics the flight of owls and therefore frightens rats away from the immediate vicinity. These “scare-owls” are erected in ripening crops where rat damage is evident.

• Chemical control – covered in section 3

• Biological control – covered in section 3

Open forum to share experiences of:

(i) Rodent impacts in different countries please elaborate in briefRodent impacts in different agro-ecosystems please elaborate in brief

(ii) Methods of management in different countries please elaborate in brief

The session concludes with some simple tools regarding problem definition of rodent problems in rural communities. These methods (decision analysis and problem definition) are covered in Norton and Pech (1988).