Damage and losses caused by rodents are well documented. Diseases transmitted by rodents to man are often widespread, and in some cases still lead to epidemics. In post-harvest systems financial losses caused by rodent pests are particularly high, because crops have attained their highest value. Damage to structures including floors, containers and even machinery are also very expensive.
The situation in the post-harvest sector is particularly annoying, as the know-how needed to economically manage rodent pest populations is available. But rodent pest management is rarely practised by farmers, storekeepers and those in the food sector and it is seldom included in extension advisory services.
This leaflet is aimed at trainers of extension staff, people responsible for managing and maintaining small- to medium-sized food stores and at the food processing sector. The aim is to convince readers that it is simple and economical to manage rodent populations and that principles of rodent pest management should be included in professional activities. The leaflet provides a general overview for rural and urban areas and small- and medium-sized stores. The principles described here apply to the post-harvest situation only, although some aspects also apply to the field situation. The information provided is based on the experience gained in rodent projects assisted by the GTZ during the last three decades.
In many cases, too much emphasis is placed on using rodenticides, overlooking many other important and effective aspects such as regular observation and sanitation, organisation and planning, proper training of staff and motivation of applicators such as farmers. This calls for a systematic approach starting in some areas even before the harvest, continuing right up to the food processing stage and includes communication and organisational skills.
It is for the above reasons that the word `control' has intentionally been replaced by the expression `management'. Control suggests that rats have already become established and are causing damage; management implies that many activities are initiated before a problem has actually arisen. The emphasis should be on preventive measures: the use of rodenticides should be seen as a last resort. This also applies to large-scale campaigns which are organised and conducted by the government and take responsibility out of farmers' hands. These campaigns are often initiated too late and are therefore a waste of effort and should be avoided in future. Instead, farmers should be taught to take responsibility for their fields and stores and to take action in time to prevent large-scale outbreaks.