Vertebrate Pest Conference Proceedings collection


Date of this Version

March 1986


Rodents are now recognized as one of the most important pests damaging crops in countries as far apart as Indonesia, Tanzania and Venezuela (Benigno and Sanchez 1984, Taylor 1984, Williams and Vega 1984). Damage to crops such as rice may be devastating during periodic upsurges in rodent numbers, with yields often reduced by 50% or more. It is being increasingly recognized, however, that continual chronic losses, which commonly occur over very large areas, are economically more significant (Buckle et al. 1985), resulting in yield losses in the range of 5 to 10% of national crops every year in many countries (Hopf et al. 1976). Crops are attacked not only in the field but also postharvest, particularly in farmers' stores at the village level. Physical losses of a further 1 to 3% of grain are typical (Hopf et al. 1976) but much more is contaminated, becoming one of the routes by which rodent-borne diseases reach humans and domestic animals (Gratz 1984). While it is difficult to estimate the prevalence of rodent-borne diseases or the consequences of their debilitating effects, public health is often considered a sufficient reason on its own to control rodents around villages. Even rodent damage to household property can be economically significant (Brooks et al., in prep.).

In spite of the clear need for rodent control at the village level, few countries have implemented effective rodent control programs directed at small-holders. Scientists tend to blame this on administrators but, in reality, many proposed programs are simply not practicable in developing countries. The largest single problem is the organization of the hundreds or even thousands of farmers who may cultivate the large area which it is technically most cost-effective to treat. One way around this problem is to encourage farmers to attempt control on their own, even when their neighbors do nothing. This approach has been followed by projects in the Philippines and Bangladesh (Benigno and Sanchez 1984, Brooks et al. 1985). Reductions in rodent damage can be achieved in this way but the farmers may easily become discouraged by the prolonged effort involved.

The alternative is to adapt the control methods to the organizational constraints. Much simpler control methods are needed, which can be carried out through the coordinated efforts of large numbers of farmers. Some examples of such projects have been described by Richards (1986) and Richards and Buckle (1986). This paper summarizes the results of three further projects which illustrate progress towards integrated management programs.