Diagnosis and control of tomato root rot disease using biological and chemical methods

The tomato crop is exposed to a number of phytopathogens, including the fungus Fusarium solani, which is a widespread soil-borne pathogen, grows in a wide temperature range, facultative parasite that lives on the plants residue and other organic matter in the soil. The aim of this study was to diagnose the causal agent of tomato root rot disease based on a field-laboratory investigation during 2019- 2020. Different fields of Babil and Karbala provinces were surveyed. Samples were collected from the roots of infected plants, then fungi were determined morphologically based on taxonomic keys. Our investigations showed that F. solani was predominant fungus, forty nine bacterial isolates isolated from the rhizoplane of healthy tomato plants, eight of them was superior in the antagonism test against the pathogen in vitro. These bacteria were diagnosed as Aneurinibacillus aneurinilyticus, Bacillus megaterium, B. pumilus, Brevibacillus laterosporus, Enterobacter cloacae, Lactococcus raffinolactis, Paenibacillus polymyxa and Pseudomonas alcaligenes, two chemical elements of magnesium sulphate and sodium silicate were used in combination with biocontrol agents to control the disease. Under greenhouse conditions, the quadruple inoculum treatment up to ten inoculum exhibited significant increase of tomato seeds germination and dry weight of the plants, and exhibited significant decrease of disease incidence and severity.