Environmental factors are triggering simultaneous efffects on the disease incidence and severity of crop diseases in agriculture. These both aspects are affected by various environmental factors including temperature, soil moisture, humidity, light, soil propertires (pH and nutrients) and atmospheric carbondioxide. The effect of environmental constraints on host and pathogen has positive, negative or neutral effects on crop disease incidence. Sometimes sole factor is responsible for profused disease incidence. On the other hand, interaction of various environmental factors causes huge intensity of diseases. Crop disease is the result of three way interaction between susceptible host, virulent pathogen and favourable environment. Various relevant informations and data were collected from recent researches and studies in the related field. Elevated carbondioxide concentration and increased temperature influence the plant disease interaction. Fungal diseases were found most prevalent at lower temperature and high humidity than bacterial diseases. Most of the diseases were found to occur in dry soils and some in wet soils due to the fact that poor germination of chlamydospores in dry soil and poor germling growth in wet soil. Deficiency of macronutrients primarily, nitrogen, phosphorus and potassium were found to be most inimical to plants resulting into physiological disorders. Effects of carbondioxide concentration on host pathogen interaction literally do not provide the unifying principles and results through different researches. So, it underscores the necessities to extend researches in this field. This review article elaborates the relationship between various environmental factors and crop diseases development and their role in increasing or decreasing the disease severity along with their management strategies.
Keywords: Crop diseases, Environmental factors, Host, Pathogen, Temperature