Project – Control fungal pathogens associated with the post-harvest rot of irish potato using pawpaw and bitter leaf plants ethanol extract

 CHAPTER ONE

Introduction

1.1    Background of the Study

Irish potato (Solanum tuberosum L.) is an important and widely cultivated crop globally contributing to food security and economic stability. Irish potato tubers like many other crops are attacked by various pathogens which cause diseases in them and out of the several tons harvested, just a fraction is utilized while most of the amount is lost to post harvest diseases (Salami and Popoola, 2007).

Fungal diseases pose a significant threat to Irish potato cultivation, with one of the most prevalent and destructive diseases being fungal rot, fungal rot caused by various fungal pathogens, leads to the deterioration and decay of potato tubers, resulting in significant post-harvest losses and reduced market value (Pinhero et al., 2009).

Fungal rot leads to the softening, discoloration, and decay of Irish potato tubers, rendering them unsuitable for consumption or commercial purposes. This rotting process not only affects the external appearance of the tubers but also compromises their internal texture and nutritional quality. As a result, affected tubers may become unmarketable, resulting in financial losses for farmers and reduced availability of high-quality potatoes in the market. Moreover pathogenic fungi associated with tuber rot contribute to the spread of fungal spores and the contamination of healthy Irish potato tubers, These pathogens cause great losses and reductions in the value of these crops but with a good system of control this can be eradicated (Stefańczyk et al., 2016).

Traditional methods of managing fungal rot in Irish potato crops often rely on the use of synthetic fungicides. While these chemicals can provide effective control, their long-term use raises concerns due to environmental pollution, potential health risks, and the development of resistance in fungal populations. Moreover, the continuous application of synthetic fungicides is not sustainable and conflicts with the growing demand for eco-friendly and sustainable agricultural practices (Al-Samarrai et al., 2012).

Therefore, there is a need to explore alternative methods of disease control that are effective, environmentally friendly, and safe for farmers and consumers. The use of medicinal plants against fungi has been practiced for centuries in various traditional medicine systems around the world. Medicinal plants offer several advantages in the fight against fungal infections (Shuping and Eloff, 2017).

Firstly, they often provide a more sustainable and environmentally friendly alternative to synthetic fungicides. Many synthetic fungicides pose concerns regarding their persistence in the environment, potential toxicity to humans and non-target organisms, and the development of resistance among fungal populations (Mahmood et al., 2016).

Medicinal plants, on the other hand, can offer a renewable and naturally-derived source of antifungal agents that may have fewer adverse effects on the ecosystem. The bioactive compounds found in medicinal plants, such as alkaloids, terpenoids, phenolic compounds, and essential oils, exhibit diverse mechanisms of action against fungi. These compounds can disrupt fungal cell membranes, inhibit essential enzymes or metabolic pathways, and interfere with fungal growth and reproduction. Additionally, medicinal plants may boost the immune system of the host organism, aiding in the natural defense against fungal infections (Stangarlin et al., 2016).

Pawpaw and bitter leaf contain diverse bioactive compounds, including alkaloids, flavonoids, and phenolic compounds, which contribute to their antimicrobial activity. When used together, these compounds may interact synergistically, leading to increased antifungal activity, inhibition of fungal growth, and a broader spectrum of action against different fungal species. Utilizing pawpaw and bitter leaf extracts as a natural control approach offers several advantages over conventional synthetic fungicides (Tripathi and Dubey, 2004).

These plant-derived compounds are generally considered safer, environmentally friendly, and sustainable. They have a lower risk of causing harmful effects to humans, animals, and beneficial organisms in the ecosystem (Chen et al., 2023).

In addition to the direct antifungal activity, pawpaw and bitter leaf extracts have been reported to possess immunomodulatory properties. These extracts can stimulate the immune system of the host plant, promoting its natural defense mechanisms against fungal infections. By enhancing the plant’s immune response, the combined use of pawpaw and bitter leaf extracts result in a more robust and effective defense against fungal pathogens (Mukherjee et al., 2014).

1.2    Statement of the Research Problem

Irish potato tubers like many other crops are attacked by various pathogens which cause diseases in them. However, post-harvest deterioration and rot caused by diverse microorganisms is the single most important factor militating against Irish potato production in Nigeria. Irish potato cultivation faces significant challenges due to the occurrence of fungal rot, which leads to substantial crop losses and economic setbacks (Mwangi et al, 2013). Traditional methods of controlling fungal diseases in Irish potato, such as synthetic fungicides, raise concerns about environmental pollution, health risks, and the development of resistant fungal strains. Additionally, the effectiveness of these chemical treatments may decline over time. High levels of rot in potato stocks can result in reduced storage life, making it challenging to store potatoes for extended periods and meet market demands. This limitation can affect the availability and affordability of potatoes as a staple food source, particularly in regions heavily reliant on potato consumption. Furthermore, the economic losses incurred by farmers due to rot-related damage can have long-term effects on their livelihoods and agricultural sustainability. These limitations highlight the need for alternative and sustainable approaches to manage fungal rot in Irish potato crops using The combination of pawpaw (Carica papaya) and bitter leaf (Vernonia amygdalina) in controlling fungal rot in Irish potato holds the potential for synergistic activity. These two plants possess individual antifungal properties, and their combined use may result in enhanced efficacy against the fungi responsible for Irish potato rot (Chikwendu et al., 2020).

1.3 Justification of the Study

Irish Potato (Solanum tuberous) is an important food source globally, and fungal rot poses a severe threat to its cultivation, resulting in extensive yield losses and economic setbacks. This research has the potential to reduce the reliance on chemical treatments, minimize environmental impact, and ensure food safety by mitigating health risks associated with chemical residues. This research could contribute to the development of effective and sustainable strategies for managing fungal diseases in Irish potato crops (Feregrino, S., 2015). The findings could provide valuable insights for farmers, agricultural practitioners, and policymakers to enhance disease control measures and improve potato production. Additionally, the study aligns with the objective of promoting sustainable and eco-friendly agricultural practices by exploring natural alternatives to synthetic fungicides. Ultimately, addressing the effects of pathogenic fungi on Irish potato tuber rot can contribute to the sustainable production, storage, and supply of high-quality potatoes, enhancing food security and supporting the livelihoods of farmers(Ngaira et al., 2015). This research is the first of its kind in Biu markets, Biu local government.

 1.4 Aims of the Study

The aim of this study is to evaluate the effects of ethanolic leaf extract of pawpaw (Carica papaya) and bitter leaf (Vernonia amygdalina) on fungi associated with the rot of Irish potato (Solanum tuberosum L.) in biu markets, Biu local government area of Borno State.

 Specific Objectives

1. Isolate and identify fungi associated with the rot of Irish potato.
2. To carryout contrail trials using aqueous extracts of pawpaw (Carica papaya) and bitter leaf (Vernonia amygdalina).

Project – Control fungal pathogens associated with the post-harvest rot of irish potato using pawpaw and bitter leaf plants ethanol extract