Abstract
A large number of physical and chemical pest control methods have been developed up to now in order to ensure the effective protection of stored tobacco and tobacco products. These methods include the use of fumigants and insecticides, treatment of baled tobacco in cold chambers, monitoring the extent of infestation with pheromone traps and, the most important preventive measure of all, maintaining a strict programme to ensure hygienic storage conditions. To date, very little serious consideration has been given to the practical use of biologically based insecticides in storage pest control. Compared with synthetically-produced pesticides, however, they often have the advantage of being significantly less toxic to users and the environment, while retaining a comparable level of effectiveness on the target organism. One reason for this neglect may certainly be found in the somewhat higher price of bioinsecticides. Another hurdle is presented by the complex mixture of different biological pesticides, which makes it more difficult to obtain official approval for their use in some countries. One possible alternative is, for example, the use of Bacillus thuringiensis endotoxin preparations. The insecticidal activity of certain B.t. kurstaki or B.t. tenebrionis strains against the tobacco moth and cigarette beetle has already been sufficiently documented. Recent research has also looked at the possibility of using natural substances, such as extracts from the neem tree (Azadirachtaindica), as storage protectants. Another very promising development is based on the autodissemination technique, whereby a modified pheromone trap in combination with entomopathogenic viruses or fungi could help to achieve a dramatic increase in mortality rates in stored tobacco pests. The chemical and biological properties of these bioinsecticides will be presented here and their advantages and disadvantages as storage protectants for tobacco discussed.