Protection Methods
 

- During cultivation

In the nursery, it is necessary to limit irrigations that are used early on, and provide maximum ventilation of the shelters. It is also recommended to treat the entire substrate solution with an anti-oomycete fungicide. In the floating seedbed systems fungicides can be applied in the nutrient solution. Rate of fungicide should be no higher than recommended to avoid potential chemical injuries.

If symptoms appear during the growing season a fungicide should also be applied at the collar level of the plants by thoroughly soaking the soil. For currently approved fungicides to combat oomycetes see  e-phy link for further information.
 
Infected plants should be removed quickly from the nurseries.
 
 
- Next crop

 A healthy or disinfected substrate should be used. Sand or soil collected from a field should not be mixed with the substrate used to fill the trays of a floating seedbed system. Soil from a field may be contaminated with pathogens that kill tobacco. The plugs should not be layed directly on the floor, especially if the floor has not been disinfected. It is best to place them on a plastic film, the seed layer of contaminated, non disinfected soil may be impregnated with a preventive anti-oomycete fungicide. The recommended measures presented in the section Nursery and planting diseases should also be applied. Foliar infections are usually controlled well with an 'anti-mildew' treatment.

At planting, one should avoid setting tobacco seedlings in very wet or cold soils; irrigations at this stage of production  should not be too excessive.
 
Attention should be paid to the quality of irrigation water coming from canals or ponds because this water may have been contaminated.

*The number of pesticides available for a specific use is constantly evolving but the author has nonetheless chosen to include the names of some registered active ingredients at the time of writing these pages. He will try to update this list as and when withdrawals and new registrations are made. When choosing your crop protection method, please refer to legislation prevailing in your country. This remark is also valid for all organic products based on micro-organisms or natural substances.