Farmer’s unseen enemy: Soilborne pathogens and its’ management

Abstract

Soil borne pathogens such as fungi, bacteria, viruses, nematodes and phytoplasmas are increasingly becoming the unseen enemy to  robust crop productivity in the tropics with particular emphasis on sub-Saharan Africa. Significant yield losses are regular occurrence in  major producing parts of the region owing to damage from pathogenic infections. The ubiquitous nature of endemic pathogens, their  extensive host ranges, and the inability to fully understand their biology and conditions that favour their multiplication and pathogenicity  are major reasons why they thrive. A teaspoon of mature grassland soil for instance, contains several millions of bacteria, fungi and  nematodes belonging to differing species. Unlike nutrient deficiency and pesticide toxicity symptoms that may be easily identified by  mere visual observations, symptoms of pathogenic infections are not easily recognized, and are sometimes mistaken for other causes  like drought, soil compaction, pesticide toxicity, and nutrient deficiency. To link a disease symptom to a pathogen, it is pertinent that both  soil and root samples must be collected and thoroughly analyzed. Hence, this article aims to highlight the major pathogenic  organisms that cause significant economic losses in crop production in the tropics, disease symptoms and protocols for identifying  symptoms as well as management strategies for keeping the pathogens population below the economic threshold.