Why annual cleaning of barns and tobacco storage is vital

The Herald

Dr Susan Dimbi and Zimazile Jazi

Tobacco Storage PESTS

TOBACCO stored on the farm can be destroyed by two very destructive insect pests, the tobacco bug (tobacco beetle).Lasioderma serricorne) and tobacco moth (Ephestia elutella). The larvae of these two pests move into the leaves, in extreme cases reducing the leaf to a handful of midribs. They also leave body fat secretions and spots, causing poor quality leaves. An established infestation is very difficult to control, and therefore the best strategy is to prevent infestations through good sanitation and vigilance. To prevent the establishment and spread of these two pests in Zimbabwe, the Plant Pests and Diseases Act (Chapter 19:08) tobacco processing and storage areas must be cleared of tobacco, tobacco scraps and waste and cleared by 31 October. , every year.


An annual cleaning exercise ensures that premises used for tobacco handling and storage are not attractive to pests and therefore unlikely to harbor them. This is because pest infestations need optimal conditions for growth and establishment, including, among others, suitable food sources and intact shelter. Working with tobacco in warehouses creates dust and debris that can settle on edges, piping, machinery, nooks and crannies. Dust and debris can provide shelter and food sources for insect pests, even after all the tobacco has been removed from the facility. By cleaning, a dead period is created for the food supply, which helps to eliminate or prevent the establishment of the target pest.


As soon as the selling season is over and all salable tobacco has been lifted from the floors, cleaning operations should begin to remove tobacco residue, dust, and shavings.

Cleaning should be done as follows:

  • Remove all items from the building, including storage containers, packaging, sorting and other equipment, and wash it with detergent and water.
  • Starting at the highest point first, use a strong stream of water to run the hose down, or alternatively, use a bucket of water and a stiff brush to wash and thoroughly clean the roof and its supporting structures.
  • Pay special attention to the upper surface of beams, walls and steam hoods where dust accumulates.
  • Hose down or wash the walls to ensure that dust, dirt and tobacco shavings are removed from the crevices, then scrub them with a stiff broom with detergent and water. Finish with a final hose or rinse with clean water.
  • Starting at the end of the floor farthest from the door and working toward the door, hose down or scrub the floor with detergent and water with a stiff brush.
  • Accumulated detergents containing building dust particles can be heavily contaminated with pesticide residues, so ensure that they are buried as far away from the doorstep as possible.
  • It is important that no products or materials (eg stored agricultural products, propak material) are stored in the building that can be fed by moths or insects.

Surface treatment with residual insecticides

After cleaning and after the surfaces have dried, it is recommended to additionally treat them with a residual insecticide, deltamethrin (Cislin).® 2.5% SC). This treatment is designed to kill insects that may enter the storage area/grading warehouse after cleaning. The recommended rate is 60 ml (2 x measuring 30 cups of fertilizer) in five liters of water applied over 100 m.2.


All debris removed from the building should be burned, as it can provide a breeding ground for insect pests. If tobacco scraps are to be used for garden compost, they should be incorporated into the soil to facilitate rapid decomposition. However, it is recommended that all scraps be destroyed in farms where tobacco beetle or tobacco moth has been detected in the previous season(s).


Traps baited with a female sex attractant and therefore highly attractive to males are useful in early detection of insect infestations and should be used in sorting and storage sheds. These traps should be placed 1.5 m above the ground and 20 m apart, or alternatively one trap may be placed every 3000 m.3. However, currently available commercial pheromone formulations for the tobacco moth are not very specific and will attract moths of other moth species.

Therefore, farmers should not assume that any moth they catch is a tobacco moth and seek the expertise of trappers. Samples can be brought to the Tobacco Research Council’s Kutsaga Scientific Station for examination and verification.


Inspectors from the Institute of Plant Quarantine Services ensure compliance with this legislation. If, on inspection, the inspector finds that the premises have not been cleaned to his satisfaction, the penalties under the Plant Pests and Diseases Act are fines, imprisonment or both. However, all growers are encouraged to maintain a high level of hygiene in their tobacco product classification and storage facilities for their own benefit, the benefit of the industry and the country.

Courtesy of the Tobacco Research Council. Kutsaga Scientific Research Station

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