Application of Nematophagous Fungi and Salicylic Acid as Biological Control Agents against Root-Knot Nematode, Meloidogyne incognita Infected Gladiolus: A Valuable Export Plant

Mohamed Abokora

doi:10.21608/ejaj.2021.183137

Abstract

This study aims to use safety agents to control the root-knot nematode, Meloidogyne incognita infected gladiolus plants (Gladiolus grandiflorus) in pots under field conditions, directly by using two nematophagous fungi, Purpureocillium lilacinumwhich parasite on nematode eggs and Hirsutella rhossiliensis which parasite on second stage juvenile of nematode , and indirectly by using treatment of salicylic acid (SA). The applied agents applied either individually or in combination, reduced nematode numbers and improved gladiolus vegetative and flowering characteristics. Tri-treatment (SA + P. lilacinum + H. rhossiliensis) achieved the best results aptly, leading to increase reduction percentage of nematode juveniles to 80.2%, decreased egg masses production and root gall index to 91.3 and 83.3%, respectively, compared with bionematicide Tervigo (Abamectin) which gave reduction percentage of nematode juveniles as 78.9%, decreased egg masses production and root gall index (80.0, 66.7%, respectively). Also, the previous tri-treatment improved flowering traits as it led to an increment proportion of flowering stem length (58.6%); number of florets/spike (46.2%) and fresh weight of inflorescence (67.9%) compared with Tervigo (43.3, 41.8 and 54.2%, respectively). In addition, tri-treatment (SA + P. lilacinum + H. rhossiliensis) significantly improved chemical properties of N, P, K and total carbohydrate (76.8, 52.4, 47.4 and 31.4%, respectively) compared with Tervigo (42.7, 23.8, 6.3 and 4.5%, respectively). The obtained results can be concluded that, both nematophagous fungi complement each other, and adding SA led to their superiority in its effectiveness for M. incognita control over the nematicide Tervigo (Abamectin). Therefore, the use of chemical nematicide in which causes harmful effects to environment and humans should be reduced or substituted with clean biological control.

Highlights

Gladiolus grandiflorus L., is a bulbous plant of great economic value as its multicolored flowers used commercially throughout the world (Mohsin et al, 2015)
Potted experiment was conducted under field conditions at the experimental farm of the Faculty of Agriculture, Menoufia University, Shebin El-Kom, Egypt to shed light on the impact of three treatments, salicylic acid (SA); Purpureocillium lilacinum and Hirsutella rhossiliensis, either single; dual or triad, in comparison with the biocide, Tervigo (Abamectin) for controlling the root knot nematode Meloidogyne incognita infected gladiolus plants and its connectedness with plants flowering; vegetative and chemical characteristics
Data in Table (2) indicate that all treatments decreased the numbers of root knot nematode, Meloidogyne incognita juveniles with varying proportions, and significant differences were observed among all treatments

Summary

Introduction

Gladiolus grandiflorus L., is a bulbous plant of great economic value as its multicolored flowers used commercially throughout the world (Mohsin et al, 2015). Gladiolus is considered as one of the best ornamental plants that can achieve a significant increase in national income by exporting its high value flowers, as they are highly needed in foreign and domestic markets, especially through the winter season (Sheela, 2008). Gladiolus plants are known to be infected with many pests and pathogens, but the most dangerous is the root-knot nematodes especially Meloidogyne incognita that infect gladiolus roots and cause great economic losses by affecting the appearance of flowers and causing damage to corms and cormles (Khanna and Chandel, 1997). M. incognita is considered an endoparasite and sedentary nematode that causes root knots on gladiolus roots and inflicts great flower damage. The use of salicylic acid helps to absorb ions, regulate the rate of photosynthesis and transpiration, as well as improve the activities of antioxidant enzymes and increase the ability of intentions to withstand abiotic stress (He et al, 2002)

Objectives

Methods

Results