Mouse monitoring, reduced feed: Cost benefit analysis

Man and mice

Monitoring mouse numbers and reducing their feed along fence lines represents an annual cost of about $650 for a sample l ,000 hectare farm on the Wimmera grey clays.

These actions may reduce the severity of mouse plagues which could cost the sample farm $35,000 (8.9 per cent of farm profit) in periods of high grain prices and $24,000 (15 per cent of farm profit) when grain prices are low.

The finding come from a study by farm management economist Kate O'Brien and agronomist Clare Dunn from the Victorian Institute for Dryland Agriculture at Horsham.


Spraying fencelines in spring. The average cost is $34/64-ha paddock. This includes cost of chemicals and one hour of the farmer's time (see table...).

The researchers said that assuming a typical farm is l,000 hectares divided into 16 paddocks approximately 60 hectares in size, the total cost of spraying fencelines around these paddocks is $544.00.

Monitoring mouse numbers.

This involves using Canola squares to monitor mouse population status. The researchers found this activity required three hours of a farmer's time prior to spring, three hours in late spring and. if mouse numbers are building, three hours prior to sowing. The nine hours of labour were estimated at $ 108 for the year.


Annual monitoring of mouse numbers and controlling their food supply should reduce the impact and occurrence of mouse plagues. Past experience has shown that chickpeas are often favoured by mice. In the 1993 south-eastern plague, many chickpea crops had to be resown. Late sowing resulted in a 10 per cent yield reduction.

The following analysis looks at the impact of resowing chickpeas for the sample farm for a situation of high grain prices and situation of low grain prices using the PRISM whole farm economic model.

High grain prices

Output from the model indicates that in a high price situation the average total farm profit over three years is $390,000. The optimum area of chickpeas in the model is 333 hectares. The cost of resowing chickpeas is $42/ha, equivalent to $ 14,000 over 333 hectares.

Further, a 10 per cent yield loss from a 2 t/ha chickpea crop equates to a loss of $62.40/ha or approximately $21.000 over 333 hectares. The combined cost of resowing and the associated yield loss totals $35,000 or 8.9 per cent of farm profit.

Low grain prices

When prices are low, the average profit of the sample farm over three years is $ 156,000. The model assumed the same 333 hectare optimum chickpea area and the same resowing costs ($14,000). However, yield losses of 10 per cent cost $31.20/ha or $ 10,389 over 333 hectares, giving a total sample loss of 24,000 or 15 per cent of the whole farm profit.

Growers should be aware that mouse control measures are most effective if taken on a district-wide basis.

Property: Mills
Distance around paddock: 3.2km
Costs of mouse control 1995
Spray width: 1.5m
Treatment: spraying
Hectares sprayed: 0.48ha
Paddock: 160 acres wheat (64ha)
Slasher width: 1.2m

ChemicalsL/hahectarestotal litres$/1total cost
Sprayingtotal kmcost/kmtotal cost
Labourtotal hourscost/hrtotal cost
Labour (spraying, mix and wash)11212.00
Spraying cost without labour for a 64 hectare paddock$21.92
Spraying cost with labour for a 64 hectare paddock$33.92

Region North, South, West, National