Effects of abiotic factors on the occurrence and development of plant diseases

Abstract

Factors of the environment where a host plant develops and grows permanently effect the beginning, development, course and, what is even more important in agricultural practice, intensity and harmfulness of a particular disease. The effects of environmental factors are of equal importance for both plant fungal and bacterial diseases but of less importance for diseases caused by phytopathogenic viruses. Although the effects are permanent, they vary in intensity due to changing environmental factors. Effects of abiotic factors, primarily of temperature and moisture, on plant diseases' intensity and development are crucial because, in most cases, if these factors are unfavorable, the disease does not develop at all despite the presence of a host plant and a pathogen. Abiotic factors affect concurrently a host plant and a causal agent. The effect on a causal agent is very important, because most pathogenic fungi do not live on a plant to the very moment of infection, therefore environmental factors have immediate effects on their development and survival. There is no universal rule about the effects of environmental factors on the occurrence and development of plant diseases, since each individual organism undergoes these effects differently.

Faktori spoljne sredine u kojoj se biljka domaćin razvija i raste stalno utiču na početak, razvoj i tok i stoje za praksu od neobičnog značaja, intenzitet, a time i štetnost određene bolesti. Taj uticaj je podjednak za mikoze i bakterioze, a od manjeg značaja je kod bolesti izazvanih fitopatogenim virusima. On je neprestan, ali je, s obzirom da se faktori spoljne sredine menjaju, različitog intenziteta. Uticaj abiotskih činilaca, a pre svega temperature i vlage, na razvoj i intenzitet biljnih bolesti je veoma bitan, tako da se u najvećem broju slučajeva, ako su oni nepovoljni, bolest uopšte ne razvija, iako su prisutni i biljka domaćin i sam patogeni organizam. Abiotski činioci ne utiču samo na biljku domaćina, nego istovremeno i na uzročnika bolesti. Taj uticaj na uzročnika bolesti je vrlo bitan, pošto se većina patogenih gljiva nalazi, sve do trenutka infekcije izvan biljke, tako da faktori spoljne sredine direktno utiču na njihov razvoj i održanje. Pošto je taj uticaj na svaki pojedini organizam različit, ne postoji opšte pravilo o uticaju faktora spoljne sredine na pojavu i razvoj biljnih bolesti. .