Susceptibility of Sweet Potato Varieties to Meloidogyne incognita and Use of Effective Microorganisms and Compost Manure for the Disease Management

Aishat Adetola Anifowose*, Nkechi Betsy Izuogu and Benoit Katchitche Sossou

Department of Crop Protection, University of Ilorin, PMB 1515, Ilorin, KW 240003, Nigeria

Received | June 25, 2023; Accepted | October 22, 2023; Published | November 15, 2023

*Correspondence | Aishat Adetola Anifowose, Department of Crop Protection, University of Ilorin, PMB 1515, Ilorin, KW 240003, Nigeria; Email: imanmytreasure@gmail.com

Citation | Anifowose, A.A., Izuogu, N.B. and Sossou, B.K., 2023. Susceptibility of sweet potato varieties to Meloidogyne incognita and use of effective microorganisms and compost manure for the disease management. Pakistan Journal of Nematology, 41(2): 135-143.

DOI | https://dx.doi.org/10.17582/journal.pjn/2023/41.2.135.143

Keywords | Plant-parasitic nematodes, Ipomea batatas, Infection, Yield losses, Bio-control microbial inoculant, Fermentation

Copyright: 2023 by the authors. Licensee ResearchersLinks Ltd, England, UK.

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).

Introduction

Sweet potato (Ipomea batatas (L.) Lam) is an important crop, especially in Africa and Asia, where its high beta-carotene content helps to preserve vision and immunity (Ukpabio et al., 2012). Elsewhere, culinary products from sweet potatoes include; pies, pancakes, sweet desserts, potato balls, porridge, stew, caramelized chunks, buns, etc. (Thaler and Safferstein, 2014). It recently found use in the clothing industry due to the abundance of anthocyanins in the purple sweet potatoes. The extracted purple sweet potato natural colorant was used to dye leather, silk, and cotton fabrics in an eco-friendly approach (Velmurugan, 2017). However, supply of this sweet tasting tuber is scarce, with Nigeria producing only 3.7% of the global production of 89.5 million tonnes (FAOSTAT, 2020). This is partly due to the 25% loss in sweet potatoes attributed to RKN found in hot climates and short winter areas (Overstreet, 2009). Root galls on sweet potatoes drain the plant’s photosynthates and nutrients (Moens et al., 2009), cause deformations and blemishes, and make tuber unmarketable and susceptible to secondary infections (Onyeka et al., 2013).

Earlier, control of this infamy had been achieved through the use of very expensive and hazardous chemicals. Hence, the need for alternatives those are cheap and environmentally friendly.

Globally, effective microorganisms (bio-control microbial inoculants) have been found to be promising in preventing and restraining pests through the introduction of beneficial microorganisms, mainly photosynthetic bacteria, lactic acid bacteria and yeasts to soils and plants (Hu and Qi, 2013). EM produce antioxidants, which modify treated soils to become disease-suppressive (Higa and Jame, 1994). The climate is changing, yet the human population continues to increase, especially in the tropics, where species are least adaptable to the impacts of climate change. Hence, the need for the existing agricultural production systems to be intensified by means other than synthetic pesticides and chemical fertilizers (Precision Reports, 2023).

Many soil-borne plant pathogens and the diseases they cause have been suppressed with the use of compost manure with varying levels of success (Atungwu et al., 2009). The organic matter provided in compost manure provides food for microorganisms, which keeps the soil in healthy, fertile, and balanced conditions (Sossou et al., 2022). The resulting increase in the microbial diversity of soil and plant ecosystems creates a healthy soil ecology that has the ability to offer defenses to plants against soil associated diseases caused by pathogenic microorganisms and parasites (Sossou et al., 2022). Thus, we hypothesized the efficacy of compost manure and EM in the management of Meloidogyne incognita infection in sweet potatoes. We evaluated and compared two sweet potato varieties for susceptibility to M. incognita, and determined the effects of compost manure and EM applied singly and in combination on the growth and yield parameters of sweet potato plants on the one hand; and on the final nematode population and gall rating on the other.

Materials and Methods

Location of the experiments

The pot experiment was conducted at the Department of Crop Protection’s screenhouse, while the field experiment was conducted at the Teaching and Research Farm of the Faculty of Agriculture, University of Ilorin (8°29’ N and 4°35’ E), located at 320 m above sea level in the Southern Guinea Savannah Zone with annual precipitation of 1000 – 1200 mm (Koppen-Geiger Classification Aw), Nigeria, between June 2018 and July 2019.

Preparation of treatments

Preparation of compost manure: Fifty (50) kg of compost manure were prepared using: 300 kg of chicken droppings, 100 kg of cattle dung, 20 kg of neem leaf, 5 kg of leguminous weeds (Crotalaria retusa and Mimosa pudica), 2 kg of Ash, 1 kg of grass clippings (Panicum maximum and Penisitum purpurum), 5 L of cow and human urine, and Water. All were obtained from the Ilorin metropolis.

Procedure: A level area at the back of the Department of Crop Protection’s screenhouse was used. A 3-inch layer of carbon rich materials (neem leaf and fresh grass clippings) was spread on the 5184 square inches area, the two inches of nitrogen source (chicken droppings, cattle dung and leguminous weeds) were spread on top of it. Then layering was continued using three inches of carbon-rich materials and two inches of nitrogen source until the pile was 4 feet tall. The pile was being wet with urine, ash and water as building continued to make it slightly damp all the way through. It was then covered with a polyethylene material in order to prevent nutrient leaching and contamination and also to secure the compost pile from rain. The pile was kept moist but not soggy and turned every two days. The temperature of the center of the pile was recorded during every turn. The first temperature recorded was 52°C and it kept increasing (as high as 62°C), but not more than that as turning continued for the composting period of about four months. The compost manure was then used when it stopped heating in the center and was dark brown, crumbly, and had an earthy smell (almost like black soil); at this point, it had a room temperature of 26°C.

Preparation of effective microorganisms: A 120 L capacity air-tight bucket was used to prepare 60 L of mixture comprising 2 L fresh milk, 40 L water, 2 L molasses, 200 g yeast, 8 kg brown weed leaves, and 2 kg green weed leaves. The weeds used were Hyptis suaveolens, Chromolaena odorata, Moringa oleifera, Azadirachta indica, Flueggu virosa and Tithonia diversifolia. All materials were obtained from the Ilorin metropolis at the Gaa Imam area, the Oja tuntun area, and the University of Ilorin farms.

Procedure: The dry materials (shredded leaves of brown or dry weeds, and green or fresh weeds) were mixed together in the 120-capacity air-tight container with an airlock. One litre of warm water was used to mix the fresh milk, yeast and molasses together in a 10 L container. The wet mixture in the 10 L container was then mixed together with the dry materials in the 120 L bucket capacity immediately to prevent the fresh milk from curdling. Water was added to the mixture and almost filled the container, leaving 10 L of space for aeration. The container was tightly covered, and fermentation was allowed until it was completely done (1 month) in the Biotechnology Laboratory of the Department of Crop Protection. The mixture was stirred every two days and the temperature monitored throughout the fermentation period (Higa, 1991; TeraGanix, 2015).

Source of vines

Two varieties of sweet potatoes (Boniato and Yellow jersey) were obtained from the Kwara State Ministry of Agriculture and Natural Resources, Offa Area Office, Kwara State.

Screenhouse experiment

Sandy-loam soil obtained from around the screenhouse of the Department of Crop Protection was steam sterilized using the barrel steam sterilizarion method at 180°F for 24 hours with firewood as the source of heat and was all used to fill 10 L plastic buckets perforated at the bottom to improve drainage. The sterilized soil was left for 72 hours to cool and reconstitute its components before planting vine cuttings of each sweet potato variety in to it (Gautam and Goswami, 2002). The screenhouse experimental design was a 2x5 factorial experiment in a randomized complete block design with five replicates. The two factors tested were: varieties at two levels (Boniato and Yellow jersey) and treatment at five levels (effective microorganisms, compost manure, effective microorganisms + compost manure, negative control and positive control).

Source of inoculum: Roots of Meloidogyne incognita infected Celosia argentea plants were obtained from the Asunlope area, Ilorin, Kwara State (Figure 1).

 

Ten kilograms of roots of Meloidogyne incognita infected Celosia argentea plants were carefully washed to remove adhering soil particles and then cut into small pieces; the galls were excised from the roots, and then placed on a petri dish containing 20 ml of distilled water to moisten the galls. The eggs were extracted using the hypochlorite method described by Hussey and Baker (1973), and juveniles were extracted using the modified Baermann tray extraction method described by Barker (1985).

Planting of vines: One vine (20 cm) with a maximum of two nodes was planted into each bucket at 3 cm depth with a spacing of 1 m between blocks and 0.5 m within blocks.

Nematode incorporation into the soil: Four (4) replicates of each variety (8 pots per block) were inoculated with 2075 eggs and 325 M. incognita juveniles at planting. The pots inoculated with M. incognita juveniles were effective microorganisms, compost manure, effective microorganisms + compost manure, and negative control pots.

Application of treatments: For the single treatment, compost manure was incorporated a week before planting at a rate of 1.5 t/ha. While, effective microorganisms were applied at planting at a rate of 4,000 l/ha.

For the combined treatment, compost manure was incorporated at planting at a rate of 0.75 t/ha with the effective microorganisms which were applied at a rate of 2,000 l/ha.

Three out of the four replicates inoculated with M. incognita juveniles (above) (6 pots per block) were treated with 100 ml of effective microorganisms, 200 g of compost manure, and 50 ml of effective microorganisms + 100g of compost manure, respectively. The treatments were banded two inches to the side and two inches deeper than the plants in order to provide the plants with a concentrated zone of nutrients and improve nutrient use efficiency.

The nematode-inoculated untreated pots served as negative controls, and the uninoculated untreated pots served as positive controls.

The soil was regularly and carefully turned during the experiment to prevent it from compacting. Watering, earthing up, and weeding were also maintained.

Field experiment

Two vines (20 cm each) with a maximum of two nodes per vine were planted into each 30 cm ridge at 3 cm depth with spacing of 1m within the ridge x 0.5m between the ridges on a field size of 12m x15m. The field experimental design was a 2x4 factorial experiment in a randomized complete block design (RCBD) with three replicates. The field was naturally infested by M. incognita, but the initial soil nematode population was estimated to be 325 juveniles per 1 kg of soil before planting and the application of treatments to the soil. Treatments were applied as in the screenhouse, and cultural practices were maintained.

Data collection

Susceptibility to Meloidogyne incognita was determined by the root knot index, where the roots were examined and rated for galling responses on a gall scaling chart (0-10) as described by Bridge and Page (1980). The mean nematode population was determined. Furthermore, the host efficiency (reproduction factor (R.F.) was calculated, as R.F. = Pf/Pi, with Pf being the final population in root and soil samples and Pi being the initial inoculum (Afolami et al., 2004)

Effects of treatment, and interaction between treatment and variety were determined by data recorded on growth and yield parameters, vine length, number of tubers, weight of tubers, etc.

Data analysis

All numerical data were subjected to a two-way analysis of variance (ANOVA) using the International Business Machine SPSS Statistics version 20, and where significant, means were separated using the Duncan’s Multiple Range Test at a 5% level of significance

Results and Discussion

The effect of treatment and variety was significant for all parameters. Treatment 3 (effective microorganisms + compost manure) with variety 1 (boniato) performed significantly higher (p=0.5) than with variety 2 (yellow jersey) and their controls (Tables 1 and 2). The same trend was observed for yield parameters (Tables 3 and 4). The treatment effect was significantly different (p=0.5), for all parameters and followed the same trends as in treatment with variety (Tables 5, 6, 7, 8).

The treated plants had a significantly lower final nematode population than control plants p = 0.5 (Tables 9 and 10).

The results of both screenhouse and field trials are shown in Tables 1-10:

The results obtained showed that the treatments tested: effective microorganisms applied singly, compost manure applied singly, and a combination of EM and compost manure; on the Boniato and Yellow jersey

 

Table 1: The effect of treatment and variety on mean vine length (cm) of Ipomea batatas infected with Meloidogyne incognita in the screenhouse.

Treatments	WAP
	1	2	3	4	5	6	7	8	9
V1T1	5.60ab	52.00b	118.00c	184.20b	188.80b	294.80c	330.60c	316.80c	303.80c
V1T2	7.80a	68.20a	175.40b	254.40ab	298.60a	390.80b	465.20b	450.80b	437.20b
V1T3	3.20bc	73.00a	209.20a	302.00a	347.80a	525.60a	568.20a	553.80a	543.70a
V2T1	5.60ab	28.40c	65.00d	78.60c	81.60c	95.20d	138.80d	131.40d	124.80d
V2T2	4.00bc	11.20de	36.80f	50.60c	50.2c	62.40def	74.30edg	69.00de	63.24efg
V2T3	4.00bc	15.40cde	49.00e	50.40c	64.20c	78.20de	90.80def	84.60def	80.40def
V1C-	3.20bc	11.40de	14.00g	66.6c	18.20c	28.20ed	34.40fd	29.20fg	20.40fg
V1C+	4.00bc	23.8cd	35.20f	51.6c	75.80c	98.80d	131.40de	113.6de	105.80de
V2C-	1.40c	2.20e	5.60g	19.80c	10.20c	12.80f	15.80g	10.20g	5.80g
V2C+	2.20c	7.20e	11.60g	16.00c	21.80c	30.80ef	35.60fg	24.80fg	20.60fg
S.E	1.0	3.70	4.30	33.75	30.80	18.70	19.80	19.50	19.60

 

Key: Means with the same letter(s) down the column are not significantly different at P= 0.05; WAP: weeks after planting; TRT 1: effective microorganisms; TRT 2: compost manure; TRT 3: effective microorganisms + compost manure; V1: Boniato; V2: Yellow jersey; S.E: Standard Error; C+: positive control;C-: negative control

 

Table 2: The effect of treatment and variety on the mean vine length of Ipomea batatas naturally infested by Meloidogyne incognita on the field per plant per week (cm).

Treatments	WAP
	1	2	3	4	5	6	7	8	9
V1T1	10.10	78.50b	139.33a	230.80a	884.40b	1257.00c	1739.70c	1678.20c	1606.33c
V1T2	9.90	78.20b	134.90a	229.70a	854.33b	1570.80b	2006.80b	1928.50b	1894.20b
V1T3	10.90	109.50a	207.40a	303.90a	1353.80a	1893.20a	2307.50a	2222.80a	2140.30a
V2T1	7.43	64.30bc	148.33a	219.33a	797.77b	1115.77cd	1390.66d	1309.90d	1261.66d
V2T2	6.77	59.30cd	143.80a	207.10a	589.30d	895.40d	915.33f	851.00f	823.33f
V2T3	7.03	65.70bc	182.40a	274.33a	644.20cd	999.40d	1113.97e	1056.50e	1021.33e
V1C	10.43	37.70d	52.00b	77.10b	165.50e	250.33e	325.60g	296.60f	260.33g
V2C	7.47	46.33cd	49.97b	56.67b	100.80e	195.80e	300.10g	265.60g	241.33g
S.E	0.43	7.80	26.57	40.38	53.90	69.80	45.90	36.60	37.40

 

Means with the same letter(s) down the column are not significantly different at P= 0.05; Key same as for Table 1; C: control.

 

Table 3: The effect of treatment and variety on the mean number of tubers (unit) and weight of tubers (gram) per plant at harvest in the screenhouse.

Treatments	Number of tubers	Weight of tubers
V1T1	2.20b	52.40c
V1T2	2.20b	74.20b
V1T3	2.80a	95.00a
V2T1	2.20b	73.20b
V2T2	1.80b	36.20d
V2T3	2.00b	52.80c
V1C-	1.00c	10.20fg
V1C+	1.00c	20.60e
V2C-	1.00c	4.90g
V2C+	1.00c	15.80ef
S.E	0.20	2.60

 

Key: Means with the same letter(s) down the column are not significantly different at P= 0.05; WAP: weeks after planting; TRT 1: effective microorganisms; TRT 2: compost manure; TRT 3: effective microorganisms + compost manure; V1: Boniato; V2: Yellow jersey; S.E: Standard Error; C+: positive control;C-: negative control.

 

Table 4: The effect of treatment and variety on the mean number of tubers (unit) and weight of tubers (gram) of Ipomea batatas naturally infested by Meloidogyne incognita on the field per plant at harvest.

Treatments	Number of tubers	Weight of tubers (g)
V1T1	27.00b	3166.70b
V1T2	30.70ab	3366.70b
V1T3	35.70ab	4766.70a
V2T1	14.00c	2716.70b
V2T2	12.33c	1366.70b
V2T3	11.00c	1450.00b
V1C	41.33a	683.33cd
V2C	8.70c	200.00d
S.E	3.50	323.20

 

Means with the same letter(s) down the column are not significantly different at P= 0.05; Key same as for Table 1; C: control.

 

Table 5: The effect of treatment on mean vine length (cm) of Ipomea batatas infected with Meloidogyne incognita in the screenhouse.

Treatments	WAP
	1	2	3	4	5	6	7	8	9
TRT 1	11.20a	80.40a	149.00b	292.60c	311.00c	390.00b	469.40b	448.10b	428.60b
TRT 2	11.80a	79.40a	212.20a	354.60b	421.20b	453.20b	539.5b	520.20b	500.40b
TRT 3	7.60b	88.40a	49.00c	428.60a	481.60a	603.80a	659.00a	638.40a	624.10a
-VE CTRL	4.60b	13.60b	19.60c	25.00e	33.20e	41.00d	39.40d	39.40d	26.20d
+VE CTRL	6.20b	31.00b	46.80c	98.20d	113.80d	129.60c	138.40c	138.40c	126.40c
S.E	1.2	6.10	16.60	16.50	18.9	25.00	26.90	26.40	26.40

 

Key: Means with the same letter(s) down the column are not significantly different at P= 0.05; WAP: weeks after planting; TRT 1: effective microorganisms; TRT 2: compost manure; TRT 3: effective microorganisms + compost manure; S.E: Standard Error; +VE CTRL: positive control; -VE CTRL: negative control.

 

Table 6: The effect of treatment on the mean vine length of Ipomea batatas naturally infested by Meloidogyne incognita on the field per plant per week (cm).

Treatments	WAP
	1	2	3	4	5	6	7	8	9
TRT 1	8.80	73.33b	143.80ab	225.00b	841.00b	1186.40b	1565.10b	1494.07b	1433.90b
TRT 2	8.33	68.80b	139.40b	218.40b	721.80b	1233.00b	1461.10b	1389.70c	1358.80b
TRT 3	8.90	87.60a	194.90a	289.10a	998.90a	1446.00a	1710.80a	1639.70a	1580.80a
Control	8.90	42.00c	50.90c	66.90c	133.20c	223.00c	312.80c	281.10d	250.80c
S.E	0.30	3.50	14.80	16.60	40.50	46.90	34.50	26.70	24.70

 

Key: Means with the same letter(s) down the column are not significantly different at P= 0.05; WAP: weeks after planting; TRT 1: effective microorganisms; TRT 2: compost manure; TRT 3: effective microorganisms + compost manure; S.E: Standard Error.

 

Table 7: The effect of treatment on the mean number of tubers (unit) and weight of tubers (gram) per plant at harvest in the screenhouse.

Treatments	Number of tubers	Weight of tubers (g)
TRT 1	2.2ab	62.80b
TRT 2	2.0b	55.20c
TRT 3	2.40a	73.90a
-VE CTRL	1.00c	7.53e
+VE CTRL	1.00c	18.20d
S.E	0.10	2.10

 

Means with the same letter(s) down the column are not significantly different at P= 0.05; Key same as for Table 5.

 

Table 8: The effect of treatment on the mean number of tubers (unit) and weight of tubers (gram) of Ipomea batatas naturally infested by Meloidogyne incognita on the field per plant at harvest.

Treatments	Number of tubers	Weight of tubers (g)
TRT 1	20.50	2941.70a
TRT 2	21.50	2366.70a
TRT 3	23.33	3108.33a
Control	25.00	441.70b
S.E	2.00	246.40

 

Means with the same letter(s) down the column are not significantly different at P= 0.05; Key same as for Table 6.

 

Table 9: The effect of treatment on the nematode population in the screenhouse.

Treatments	R.F.	Initial nematode population	Final nematode population	Gall rating
TRT 1	0.96	2400.00	2286.50d	1
TRT 2	0.81	2400.00	1931.00c	1
TRT 3	0.59	2400.00	1437.00b	1
-VE CTRL	1.15	2400.00	2761.00e	2
+VE CTRL	0.00	0000.00	0000.00a	0
S.E			62.6

 

Means with the same letter(s) down the column are not significantly different at P= 0.05; Key same as for Table 5.

 

Table 10: The effect of treatment on nematode population in the field plot.

Treatments	Initial nematode population	Final nematode population	R.F.
TRT 1	325.00	7.80a	0.02
TRT 2	325.00	11.20a	0.04
TRT 3	325.00	6.80a	0.02
Control	325.00	19.33b	0.06
S.E.		2.00

 

Means with the same letter(s) down the column are not significantly different at P= 0.05; Key same as for Table 6.

 

sweet potato plants differed significantly from the controls for all growth and yield parameters (Tables 5-8) and reduced the nematode population in the soil (Tables 9 and 10), thus confirmed as having nematicidal effects. However, both varieties used: Boniato and Yellow jersey sweet potatoes were susceptible to M. incognita infection.

The general increase in the growth and yield of Boniato and Jersey sweet potatoes as evidenced in Tables 1-4 may be attributed to the fact that the application of treatments improved the health of the plant and possibly induced resistance against the nematodes and modified the soil to become unfavorable for the pathogens’ growth. Izuogu and Usman (2019) reported that compost tea from poultry droppings and cow dung tea gave appreciable yield and managed the population density of Pratylenchus zeae on maize; furthermore, improved crop nutrition following treatment application may lead to tolerance of plant-parasitic nematodes and thus an increase in growth and yield of the plants. Efficient translocation is reported to positively affect peanut plant yield (Osman et al., 2020).

The significantly better result recorded in Boniato and Jersey plants treated with a combination of effective microorganisms and compost manure as shown in Tables 1-4 may be due to the increase in the population of beneficial microorganisms in the soil which helps control root-knot nematode disease through competitive exclusion as explained by Higa and Wididana (1991). While the organic matter provided in compost manure provides food for microorganisms which further suppresses M. incognita and increases recycling of their nutrients for uptake by plants, Hu and Qi (2013) reported that the application of compost manure in combination with effective microorganisms greatly increased wheat straw biomass, grain yield, and the number of free living nematodes, thereby increasing nutrient recycling and decomposition, compared with traditional compost and control treatments. This agrees with Sossou et al. (2022), who reported that the combination of EM and compost manure enhanced the tolerance of tomato plants to M. incognita.

Stunted plants, chlorosis, decayed roots, and extreme yield reductions in some of the control plants, as shown in Tables 1-8 could be attributed to a higher population of nematodes in these plants, as reported by Moens et al. (2009).

Unlike the field experiment, galls observed in the negative control plants of both varieties in the screenhouse experiment ranged from 1-2. This, coupled with a R.F. greater than 1 in all the negative controls in the screenhouse (Table 9) compared to a R.F. less than 1 on the field (Table 10), may indicate proliferation of nematodes and their active penetration due to the absence of EM and compost manure which is further aided by the exclusion of other soil microorganisms in the pot experiment. This is in harmony with the findings of Izuogu et al. (2016).

However, the reduction in root-knot index (Table 9), the difference in final nematode population from the initial population and a R.F. less than 1 for M. incognita in treated plants (Tables 9 and 10) may be attributed to the direct toxicity of nitrogenous compounds in compost manure as indicated by Kankam (2015) on carrot, and antioxidants present in EM to eggs and/or juveniles; modification of habitat by application of EM to become disease-suppressive soils, thus reducing the root-knot nematodes population density (Higa and Wididana, 1991).

According to the present studies, sweet potato plants treated with a combination of EM and compost manure were more tolerant of M. incognita and gave significantly higher yields in spite of the RKN infections. These findings thus demonstrated a combination of EM and compost manure, as potential cost-effective and a novel natural management strategy that can help sweet potato growers and agricultural practitioners seeking sustainable solutions to manage RKN address not only the immediate issue of root-knot nematodes, but also contribute to the overall well-being of the agricultural system.

Conclusions and Recommendations

Susceptibility of sweet potatoes to M. incognita infection reduces yield. The EM technology, along with compost manure, has a nematicidal effect on Meloidogyne species in sweet potato plants. If optimized, the infection, proliferation and active penetration of RKN in sweet potato will be greatly inhibited, the growth and yield of the sweet potato plant, enhanced and the prevention of galling on roots is assured.

Besides the diverse environmental applications of EM, such as bioremediation, especially in Asian countries, farmers worldwide should be provided with information on how to produce effective microorganisms and combine them with compost manure in an integrated management practice so as to achieve sustainable agriculture as the climate continues to change and the world population continues to increase.

Acknowledgements

My gratitude is to Almighty Allah, who has taught man that which he knew not, and with whom all things are possible. I also appreciate Dr. Apalowo Oluropo for his guidance and meaningful contributions to my work.

Novelty Statement

This research paper highlighted a compelling and innovative approach to tackling the issue of root-knot nematodes management through the utilization of effective microorganisms and compost manure. The peculiarity of its methodology lies in its comprehensive analysis of the interaction between effective microorganisms, compost manure, and root-knot nematodes

Author’s Contribution

AAA: Project administration, investigation, data curation, resources, formal analysis, writing-original draft, writing-review and editing.

NBI: Conceptualization, supervision, methodology.

BKS: Data curation, project administration, investigation.

Conflict of interest

The authors have declared no conflict of interest.

References

Afolami, S.O., Atungwu, J.J., Orisajo, S.B. and Odeyemi, S., 2004. Going beyond gall index in studying and reporting resistance to root knot nematodes. Niger. J. Plant Prot., 21: 25-32.

Atungwu, J.J., Ademola, A.A. and Aiyelaagbe, I.O., 2009. Evaluation of organic materials for inhibition of nematode reproduction in soybean. Afr. Crop Sci. J., 17: 167–171. https://doi.org/10.4314/acsj.v17i4.54292

Barker, K.R., 1985. Nematode extraction and bioassays. In: Baker, K.R., Cater, C.C., and Sasser, J.N. (eds.) An advanced treatise on Meloidogyne. Volume II: Methodology, Graphics, North Carolina State University, United States. pp. 19-35.

Beck, H.E., Zimmermann, N.E., McVicar, T.R., Vergopolan, N., Berg, A. and Wood, E.F., 2018. Present and future Koppen-Geiger climate classification maps at 1-Km resolution. Sci. Data, 5: 180214. https://doi.org/10.1038/sdata.2018.214

Bridge, J. and Page, S.L., 1980. Estimation of root-knot nematode infestation levels on roots using a rating chart. Trop. Pest Manage., 26(3). https://doi.org/10.1080/09670878009414416

Food and Agriculture Organization of the United Nations Statistics Division (FAOSTAT), 2020. Sweet potato production in 2019; World Regions/Production Quantity from pick lists. Available at http://www.feedipedia.org/ (accessed 24 March 2021).

Gautam, C. and Goswami, B.K., 2002. Different combinations of Neem cake and carbofuran against Meloidogyne incognita on vigna radiate. J. Nematol., 12: 106-110.

Higa, T., 1991. Effective microorganisms: A biotechnology for mankind. In proceedings of the first international conference on kyusei nature farming. U.S. Department of Agriculture, Washington, D.C., USA, pp. 8-14.

Higa, T. and Wididana, G.N., 1991. Changes in the soil microflora induced by effective microorganisms. Proceedings of the first international conference on Kyusei nature farming. U.S. Department of Agriculture, Washington, D.C., USA, pp. 53-162.

Higa, T. and James, P., 1994. Beneficial and effective microorganisms for a sustainable agriculture and environment. International Nature Farming Center, Atami, Japan, pp. 16.

Hu, C. and Qi, Y., 2013. Long-term effective microorganisms’ application promotes growth and increase yields and nutrition of wheat in China. Eur. J. Agron., 46: 63–67. https://doi.org/10.1016/j.eja.2012.12.003

Hussey, R.S. and Baker, K.R., 1973. Comparison of methods for collecting inocula of Meloidogyne spp., including a new technique. Plant Dis. Rep., 57: 1025-1028.

Izuogu, N.B., Abolusoro, S.A. and Yakub, L.B., 2016. Nematicidal potential of aqueous extract of Hyptis suaveolens in the management of root-knot nematode, Meloidogyne incognita of some cowpea cultivars. Croatian J. Food Sci. Technol., 8: 15-19. https://doi.org/10.17508/CJFST.2016.8.1.05

Izuogu, N.B. and Usman, S., 2019. Efficacy of compost tea from animal waste in the management of Pratylenchus zeae infecting two maize varieties. J. Agric. Res., 57(3): 167-173.

Kankam, F., 2015. Effect of poultry manure on the growth, yield and root-knot nematode (Meloidogyne spp.) infestation of carrot (Daucus carota L.). Arch. Phytopathol. Plant Prot., 48(5). https://doi.org/10.1080/03235408.2014.893639

Moens, M., Perry, R. and Starr, J., 2009. Meloidogyne species- a diverse group of novel and important plant parasites. CAB Int: Wallingford, UK pp. 1-17. https://doi.org/10.1079/9781845934927.0001

Onyeka, T.J., Okorocha, E.A. and Anioke, S.C., 2013. An overview of pests and diseases of sweet potato. In: Ukpabio, U.J. and Nwosu, K.L. (ed), yam, cocoyam and sweet potato production and post-harvest management. National Root Crops Research Institute. NRCRI, Nigeria. pp. 265.

Osman, H.A., Ameen, H.H., Mohamed, M. and Elkelany, U.S., 2020. Efficacy of integrated microorganisms in controlling root-knot nematode Meloidogyne javanica infecting peanut plants under field conditions. Bull. Natl. Res. Centre, Giza, Egypt, 44: 134. https://doi.org/10.1186/s42269-020-00366-0

Overstreet, C., 2009. Nematodes. In: Loebenstein, G. and Thottappily, G. (ed). The sweet potato. Springer Sci, Germany. pp. 131-155.

Precision Report, 2023. Effective microorganisms (EM) market. Available at https://www.marketwatch.com/press-release/effective-microorganisms-em-market-2030-2023-05-12. (accessed 12 May 2023).

Sossou, B.K., Izuogu, N.B., Anifowose, A.O. and Ahamefule, H.E., 2022. Controlling root-knot nematode Meloidogyne incognita in tomatoes using modified effective microorganisms-fermented plant extract and compost manure. Int. J. Recycl. Organic Waste Agric., 11: 427-436.

SPSS Predictive Analytics, 2017. What’s new in SPSS Statistics 25 and Subscription. Available at http://www.developer.ibm.com/ (accessed 18 July 2017).

TeraGanix, Inc., 2015. Higa, T. EM: A holistic technology for humankind. Available at http://www.pssurvival.com/ (accessed 27 November 2015).

Thaler, M. and Safferstein, D., 2014. A curious harvest: The practical art of cooking everything. Quayside Publishing Group, United States. pp. 129.

Ukpabio, U.J., Ekeledo, E.N. and Ezigbo, V.U., 2012. Potential use of roots of orange fleshed sweet potato genotypes in the production of B- carotene rich chips in Nigeria. Afr. J. Food Sci., 6: 2. https://doi.org/10.5897/AJFS11.186

Velmurugan, P., 2017. Extraction of natural colorant from purple sweet potato and dyeing of fabrics with silver nanoparticles for augmented antibacterial activity against skin pathogens. J. Photochem. Photobiol., 173: 571-579. Available at http://www.ncbi.nlm.nih.gov, https://doi.org/10.1016/j.jphotobiol.2017.07.001