management of meloidogyne incognita in yam-based cropping systems with cover crops

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Management of Meloidogyne incognita in yam-

based cropping systems with cover cropsby

A.O. Claudius-Cole,B. Fawole,R. Asiedu and

D.L. Coyne Crop Protection and Environmental Biology, University of Ibadan, International Institute of Tropical Agriculture, Ibadan, Nigeria.

Presented by

Temitayo Oluwatosin, Aremu

May, 2015


• Nigeria produces 70-76% of world yam

production (FAO data, 2007,1985).

• Yams contributes ~30% of the

calorie intake in W. Africa (FAO, 2007)

Uses• Feed for livestock

• Food for humans

• Pharmaceutical benefits

• Socio- Cultural value

Introduction

Pounded yam and egusi

Boiled yam and egg

Contraceptives


Yam Production Constraints

• Availability and cost of seed yam

• Cost of labour

• Pests and diseases– Mealybugs– Yam beetles– Anthracnose – Nematodes• Scutellonema bradys• Meloidogyne spp.• Pratylenchus coffeae

Pratylenchus coffeae

Meloidogyne spp.

Scutellonema bradys


Impact of Nematodes on Yam

• 47% of tubers on sale in Nigeria markets are infested with S. bradys (Wood et al.,1990)

• 34%-52% reduction in price of Meloidogyne

infected tubers (Nwauzor and Fawole, 1982)

• Yam dry rot causes reduction in quantity,

market value, storage & edible part of tubers

Infested tuber Healthy tuber

Galled tuber

Dry-rot on cut yam tuber


Objective

• To evaluate the use of some cover crops as inter-crops, for root-knot nematode management in yams.


Materials and Methods

• Four cultivars of Dioscorea spp;

• D. Alata: TDa 294 (Hawaiian) and TDa 92-2 (Shagbe) and

• D. Rotundata: TDr 608 (Nwopoko) and TDr 93-3(Danacha)

• 10 cover crops: Aeschynomene histrix ,Cajanuscajan , Centrosema pubescens , Crotalaria juncea,Lablab purpureus ,Mucuna pruriens , Tageteserecta , Pueraria phaseoloides ,Stylosanthesguianensis and Vigna unguiculata(Ife Brown)


Materials and Methods cont…• Examples of some of the plants used as cover crops.

Crotalaria juncea

Tagetes erectaAeschynomene histrix

Centrosema pubescens

Stylosanthes guianensis


Pot Experiments

• Tubers were cut into 50 g setts and pre-treated

• Planting was in 23 cm diameter pots containing 5 l of steam-sterilized soil.

• Cover crops planted 1 week after transplanting yams

• Inoculation was with 5000 eggs using a syringe applied directly into four holes made in the soil and zero nematodes as control.

• RCBD with 6 replicates in the screen house


Field experiments

• Yam setts were cut into 150 g setts, treated,pre-sprouted before transplanting

• Cover crops were planted one week after transplanting

• Field experiment was RCBD in split plot layout

• 4 replicates with 10 plants per plot


Materials and Methods cont…

• Extraction of eggs/juveniles of RKN from galled roots of Celosia argentea (Hussey & Barker 1973)

• Inoculation of 10,000 eggs of M. incognita per plant

and no-nematode control on the field

Galled Celosia rootsExtract poured through sieves

NaOCl


Data Collection

• Tubers were harvested 6 MAP, weighed and scored for nematode damage using 1- 5 damage scale

• Extraction of Meloidogyne spp. from

tubers and roots (Hussey and Baker 1973)

• Extraction from soil via modified

Baermann tray method (Coyne et al., 2007).

• Nematodes were counted with a dissecting microscope

• Data recorded and Reproductive factor(RF) determined;

where Pf/Pi (Pf = final population and Pi is initial nematode population)

Soil Extraction


Data Analysis

• Transformation of percentage data and nematode counts using arcsine or Log (x þ 1) where appropriate.

• All data were subjected to analysis of variance (ANOVA)

• Statistical analysis was conducted using SAS program (SAS Institute Inc., 2001)

• Means was separated using Student Newman Keuls(SNK) at 5% level of significance and standard error were used where appropriate.


RESULTS


Table 1. Effect of Cover Crops on Tuber Damage, Number of

Meloidogyne incognita in Tuber, Soil, and Roots of Cover

Crops and Nematode Reproductive Factor in Pot Experiment

Cover crop Tuber

damage

score

2MAS

M. incognita

Population in

tuber (5 g)

2MAS

M. incognita

Population in

Soil (100

cm3)

M. incognita

Population in

Root (5 g)

Reproducti

ve

factor (RF)

T. erecta 1.0d 12.6d 0.4d 0.4d 0.4c

C. juncea 1.0d 4.1d 0.7d 0.6d 1.0c

A. histrix 1.0d 11.1d 0.5d 0.8d 0.9c

S. guianensis 1.1cd 15.0d 0.9cd 10.1d 1.9bc

P. phaseoloides 1.2cd 80.4c 3.5b 9.2d 2.2bc

C. pruriens 1.3c 9.0d 0.6d 3.3d 1.8bc

C. cajan 1.4c 151.3bc 5.0a 27.2c 4.3b

No cover crop 2.4b 406.2a 1.2c 3.9b

L. purpureus 3.1a 229.8b 3.4b 151.6a 16.4a

V. unguiculata 3.3a 840.2a 5.5a 78.0b 12.5a


Table 2. Effect of Cover Crops on Tuber Damage, Number of

Meloidogyne incognita in Tuber, Soil, and Roots of Cover Crops

and Nematode Reproductive Factor in Field Plots.

Cover crops

Damage

score of

yam tuber

(3 MAH)

Mean

number of

nematodes in

tuber (5 g)

Mean

number of

nematodes

in

soil(100cm3)

Mean number of

nematodes in

cover crops

roots(5 g)

Reproducti

ve Factor

(RF)

A. histrix 1.0d 13.4c 0.4d 0.3c 0.7c

T. erecta 1.0d 2.4c 0.0d 0.1c 0.2c

C. juncea 1.0d 0.0c 0.0d 0.1c 0.0c

M. pruriens 1.0d 25.7c 0.6d 0.9c 1.1c

C. pubescens 1.1d 33.3c 1.0d 3.0c 0.9c

P. phaseoloides 1.1d 46.7c 0.4d 1.5c 2.3c

S. guianensis 1.2cd 148.6bc 1.0d 0.9c 1.5c

C. cajan 1.5c 541.1b 8.2c 59.8b 32.5b

No cover crop 1.9b 392.1b 6.0c ---- 28.6b

L. purpureus 2.8a 1574.2a 10.5b 76.5b 67.8a

V. unguiculata 2.9a 1095.5a 16.3a 111.6a 53.8a


Results cont...

16

• Nematode densities were minimal and damage absent on tubers intercropped with C. juncea, A. histrix, and T. erecta2 MAS in both field and pot experiments• Tubers intercropped with S. guianensis, P. phaseoloides, M. pruriens and C. pubescens had slight nematode damage• Tubers intercropped with C. cajan, L. purpureus, V. unguiculata or no cover crop had moderate to severe symptoms of damage. • C. cajan, L. purpureus, and V. unguiculata supported high nematode populations and RF in pot experiments.


Discussion

• C. juncea, A. histrix and T. erecta were found to be effective in managing M. incognita on yams

• Supports results of McSorley et al. (1994; 1999) and Piedra-Buena et al. (2008)

• M. pruriens, C. pubescens, P. phaseoloides and S. guianensis suppressed the effect of M. incognita

• Supports results of Rodriguez-Kabana et al. (1992) and Kokalis-Burelle et al. (2005)

• L. pupureus, V. unguiculata and C. cajan were highly susceptible to M. incognita

• Supports results of Otipa et al. 2009, Adegbite et al.,2005


Discussion cont...

• Suppression of RKN by cover crops can be via acting as a non-host or a poor host (Rodríguez-Kabana et al., 1992);

• Some produce allelopathic compounds that are toxic to

nematodes (Halbrendt, 1996; Wang et al., 2001)

• Stimulation of soil organisms that compete with or attack nematodes (Hooks et al., 2010).

• D. rotundata had higher susceptibility to M. incognita than D. alata

• M. incognita in tubers causes increased respiration of the tuber (Fawole and Evans, 1989) which contributes to storage weight loss.


Conclusion

• A. histrix, T. erecta and C. juncea should be incorporated into IPM strategies for Meloidogyne species management

• M. pruriens, S. guianensis, C. pubescens and P. phaseoloides were moderately susceptible to M. incognita and may be used to reduce their Meloidogyne species populations

• C. cajan, L. purpureus and V. unguiculata were susceptible to M. incognita and should be avoided in cropping systems involving susceptible crops

management of meloidogyne incognita in yam-based cropping systems with cover crops

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