Experiments were conducted at the Crop and Environmental Laboratory of the Joseph Sarwuan Tarka

University (formerly, Federal University of Agriculture), Makurdi to assess the occurrence of seed-borne fungi

on nine varieties (Kampala, Kwankwaso, Jawunde, Samnut 21, Samnut, 22, Samnut 23, Samnut 24, Samnut 25

and Samnut 26) of groundnut (Arachis hypogaea L.) and to test the effect of ginger (Zangiber officinale)

extract on Aspergillus niger and Fusarium verticilloides. Detection of seed-borne fungi was done by standard

blotter methods while mycelial growth of A. niger and F. verticilloides were recorded on potato dextrose agar

(PDA) culture medium. All the experiments were carried out in Completely Randomized Design replicated as

appropriate. The fungi detected were Aspergillus flavus, Aspergillus niger, Fusarium verticillioides, Fusarium

solani and Botryodiplodia theobromae. A. flavus and A. niger were the most predominant fungi encountered.

control. Ginger extract at 30% w/v gave 100% inhibition of mycelial growth in F. verticilloides compared with

the control. It is concluded that groundnut varieties are infected by various fungal organisms and ginger

(Zangiber officinale) extract reduced the growth of A. niger and F. verticilloides infecting groundnuts

Groundnut (Arachis hypogaea L.) belongs to the genus Arachis in the family Leguminosae. Groundnut has

prospects as a major source of income to farmers as it serves as cash crop in most rural communities (Awoke,

2003, Taru et al., 2010). Groundnut is the thirteenth most important food crop and fourth most important

oilseed crop of the world (Radha et al., 2011). It contains 48-50% oil, 26-28% protein and 11-27%

carbohydrate and also contain minerals and vitamins that supplement the dietary requirement of humans and

enhance other biochemical changes of grains (Bhattacharya and Raha, 2002, Bilgrami, et al, 1976). Most seed

infections occur in the field before harvest and these infections are influenced by weather conditions between

flowering and maturity (Mehrota and Aggrawal, 2006). Warm humid conditions during this period often

results in heavy pod and seed infection. It has been reported that seed-borne transmission of pathogens is

responsible for the perpetuation of plant diseases leading to drastic yield reduction (Oluma and Nwankiti,

2007). Hundreds of seed-borne fungi, both pathogenic and saprophytic have been isolated and identified

Many seed borne pathogens are found outside the embryo in the seed coat, pericarp or endosperm. Others are

transmitted as seed contaminants on the seed surface. Some seed borne pathogens can be found both inside and

outside the embryo (Aggrawal, 2005). A few of these pathogens grow directly into the young plant and cause

al.,2010). Plant extracts are environmentally friendly, relatively safe and are biodegradable compared with

synthetic chemicals (Sukanya et al., 2011; Khan and Nasreen, 2010; Enikuomehin, 2005; Gurjar et al. 2012).

The use of plant extract on stored groundnut seeds have been shown to possess potent antifungal, antibacterial,

insecticidal and nematicidal activity (Amvam et al.,1998; Isman,1999; Nguefack et al., 2005; Nguefack et al.,

2007); Oka et al., 2000). The extract of ginger has not been tested on seed-borne fungi on the SAMNUT

varieties of groundnuts in Benue State. This work was therefore carried out to determine the fungal organism

associated with SAMNUT varieties of groundnut and determine the effect of seed treatment with ginger extract

on their occurrence.

Experiments were conducted at the Crop and Environmental Protection Laboratory of the College of

24 months of storage of groundnut seeds harvested from a field experiment. The seeds were tested for

occurrence of seed-borne fungi using standard blotter method. The groundnut seeds were sterilized in 10 %

Sodium hypochlorite for 1 minute and rinsed in three changes of sterile distilled water (SDW). Ten seeds were

placed on moist blotter in sterilized 9 cm diameter Petri dishes moistened with 10 ml SDW and incubated for

seven days at ambient conditions of light and temperature. The treatments (varieties) were arranged in

completely randomized design, replicated 10 times (10 plates per variety). The incubated seeds were observed

for fungal growth and fungi detected were sub-cultured on PDA to obtain pure cultures. Isolated fungi were

identified using identification manual by combining morphological and molecular data to enhance accuracy in

species-level identification at the Department of Crop Protection, Ahmadu Bello University, Zaria, Nigeria.

Number of seeds infected by each fungi detected in each of the varieties were recorded,

Fresh ginger materials were purchased from Makurdi North-Bank market, peeled and rinsed with sterile

distilled water (SDW). Various weights of ginger consisting of 10 g, 20 g, 30 g were ground using a blender

and infused with 100 mls of SDW in 250 ml conical flask and filtered using double layer cheese cloth to give

10, 20 and 30 % w/v concentration respectively. Two fungi; Aspergillus niger and Fusarium verticilloides

earlier isolated were used as test fungi. The treatment were various concentrations of ginger extracts consisting

of 0 % w/v, 20 % w/v, 30 % w/v, and 40 % w/v set up in completely randomized design and replicated three

times.

The extracts prepared were used to amend PDA (Potato Dextrose Agar) at the various concentrations (0, 20,

30, 40 % w/v), The control (0 % w/v) was PDA without extract. The amended media was prepared by adding 4

grams of PDA (Lab M) to 100ml plant extracts of the various concentrations. The flasks were autoclaved at

121

C for 15 minutes (Nduagu et al., 2008) after which they were removed and allowed to cool on a laminar

(Obagwu et al., 1997).

temperature (30±2

C) for six days after which diameter of the test fungi were measured using a meter rule

along two diagonal lines drawn on the reverse side of each Petri dish. Percentage reduction in mycelial growth

Where;

P

= % reduction in mycelial growth,

P

= mycelial growth in the untreated medium (control),

˃ 51- ˂ 100 % inhibition (Effective) ,

100 % inhibition (Highly effective) (Okigbo et al., 2009)

The data were subjected to analysis of variance (ANOVA) using GENSTAT (17

edition). and means were

separated using Fisher’s Least Significant Difference (FSLD) at 5% level of probability (Obi,). 2002

The morphological characteristics of seed-borne fungi encountered and detailed description of the colony are

presented in Table 1. The fungi encountered included, Aspergillus flavus, Aspergillus niger, Fusarium

verticillioides , Fusarium solani, and Botryodiplodia theobromae. Table 2 shows the occurrence of the seed

borne fungi detected on groundnut, in this trial. Aspergillus flavus and A. niger were the most predominant

24 and SAMNUT 26. Occurrence of Fusarium verticilloides was significantly (P<0.05) lower in SAMNUT

24 compared with the other varieties except SAMNUT 26. The highest occurrence of F. verticilloides was on

the variety Kampala. Fusarium solani was significantly (P<0.05) higher in Jawunda followed by Kwankwaso,

and Kampala varieties. F. solani was not detected in SAMNUT 22, 24, 25 and 26 and there was no significant

Table 1: Morphological and microscopic presentation of fungi isolated from groundnut

Bahraminejad, 2012; Iwuagwu et al., 2019).

The inhibition pattern observed agrees with findings by Nguefack et al. (2007), who reported similar

suppression of fungal pathogens in rice using essential oils. Navoda and Anupama (2022) tested extracts of

of botanical fungicides as safer and eco-friendly alternatives to synthetic chemicals, which often pose

environmental and health hazards (Isman, 1999; Sukanya et al., 2011; Navoda and Anupama, 2022).

The complete inhibition of F. verticillioides by 30 % ginger extract is particularly significant due to the

toxigenic potential of Fusarium species, which produce harmful mycotoxins affecting human and animal

health (Bhattacharya and Raha, 2002). The suppression of such fungi through natural, biodegradable agents

provides a valuable tool for improving post-harvest seed health and food safety, particularly in resource-

limited communities in many rural settings in Africa.

While the study demonstrates promising results, the findings are limited to in vitro conditions. Therefore,

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