Chemical injuries
 

The photos on this page summarise the various yellow to white spots (figures 1 to 4) caused by some chemical products, inadvertently or not, applied on tobacco (chemical injuries).

 
Herbicides, in particular by disrupting the photosynthetic activity of plants, cause yellow spots on some leaves. Note that the affected tissues can progressively turn white. Be aware that the use of a herbicide on or close to crops is never totally harmless. It may only be done by using specific doses and during particular stages of development of the crop: The risks of chemical injuries never totally vanish. Other pesticides, for example, mixtures of insecticides and fungicides or fertilisers, may likewise cause chemical injuries on tobacco. 

 
The origin of a chemical injury is difficult to determine. As a matter of fact, producers often refuse the possibility of having committed an error or caused damage. Let us recall that in most cases the study of symptom distribution in time and space confirms the hypothesis of a chemical injury.

 
For further information on chemical injuries see the fact sheet of Various chemical injuries in the section Abnormal leaf colour.