Among cereal crops wheat is a major food and important commodity of the world grain market.In India it is second important food crop.Since air pollution is a relatively new factor in agriculture, its impact including on diseases caused by various biotic pathogens needs to be thoroughly examined. This book is a step to find out relationship between two groups of pathogens: Anguina tritici (biotic) and air pollutants i.e. SO2, acid rain, fly ash (abiotic) on a common host (wheat). The host-parasite relationships of both pathogens were different. The expected impacts of both pathogens separately in artificial treatments on wheat were direct.Three type of interaction may exist between these air pollutants and A. tritici in a common pathosystem, synergistic, antagonistic and neutral relationship.However, combined impacts were different. Both the pathogens interacted antagonistically, whenever they combined together irrespective of pre, post and concomitant inoculations. That’s why according to antagonistic interaction formula, the combined effects of both pathogens (P1 and P2) were always found less than the sum of their individual effects (effect P1 P2 < effect P1 + effect P2).