Ditylenchus africanus

Ditylenchus africanus	Contents	Rev 11/19/2019
Peanut Pod Nematode	Classification	Hosts
	Morphology and Anatomy	Life Cycle
Return to Ditylenchus Menu	Economic Importance	Damage
	Distribution	Management
Return to Anguinidae Menu	Feeding	References
	Go to Nemaplex Main Menu	Go to Dictionary of Terminology

Classification:

Tylenchida Tylenchina Tylenchoidea
Anguinidae
Anguininae
Ditylenchus africanus Wendt, Swart, Vrain and Webster, 1995

Morphology and Anatomy:

Ditylenchus africanus differs from D. destructor mainly in stylet and spicule lengths and in RFLPs and rDNA characteristics.

Reported median body size for this species (Length mm; width micrometers; weight micrograms) - Click:

Distribution:

Common in peanut growing areas of the Republic of South Africa and only reported from that area.

Economic Importance:

Not known in the U.S. Considered an exotic pest of potential significance.

The chances of introduction of this nematode into the United States are considered limited because imported peanut seeds are used for food processing.

Plant breeders should be extremely cautious in importing peanut seeds from South Africa.

Economic Considerations in South Africa

Peanuts are graded for quality according to law (Agricultural Products Standards Act No. 119 of 1990). Based on evaluation of blemish and other criteria, peanuts are graded as:

Grade Category	Average % Reduction in price from Choice Edible
1. Choice Edible Grade	0%
2. Standard Edible Grade	15%
3. Diverse Grades	50%
4. Crushing Grade	65%

Therefore management strategies that maintain or enhance yield and minimize blemish of kernels are of primary importance.

(McDonald et al., 2005)

Feeding:

D. africanus has fungivorous habits and can be reared in fungal cultures (Aspergillus sp., Botrytis sp., etc.)

Hosts:

Peanut (Arachis hypogaea) is the principal host. Other agronomic crops and weeds can be infected without showing any symptoms or damage.

D. africanus has fungivorous habits and can be reared in fungal cultures (Aspergillus sp., Botrytis sp., etc.)

Unlike D. destructor, D. africanus does not infect potato.

For an extensive host range list for this species, click

Life Cycle:

Ecophysiological Parameters:

For Ecophysiological Parameters for this species, click	If species level data are not available, click for genus level parameters

Ditylenchus africanus is disseminated with infected peanut hulls and blemished seeds.

The nematode develops and reproduces in pod tissues causing necrotic discoloration and black or brown stripes. The nematode can also invade the seeds, which appear dark and shrunken. It is able to survive in the hulls and in seeds.

Effects of D. africanus in peanut production include:

Premature germination of seeds prior tio harvest.
Increased proportion of blemished kernels.
Reduced kernel fresh weight.
Pods broken from weakened peg connections.

(McDonald et al. 2005)

Important pest on the 250,000 acres of peanuts in South Africa where it reduces yield and also quality by discoloring seed testa.

Discolored seed is downgraded into lower quality (and value) classes: Export>Domestic>Processing (see Economic Importance). The price changes associated with downgrading are much more significant than the direct yield loss.

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Management:

Early harvest of peanuts avoids some economic loss in South Africa. Cultivars are selected that allow early harvest in specific biogeographic regions (Venter, DeWaele, and Meyer, 1991).

Host Plant Resistance, Non-hosts and Crop Rotation alternatives:

For plants reported to have some level of resistance to this species, click

Partial resistance has been developed from local African germplasm, elite breeding lines and hybrids. The resistance is overcome at high nematode infestation.

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References:

Venter, DeWaele, and Meyer, 1991 - Journal of Nematology

CAB International. 2001. Ditylenchus africanus in: Crop protection compendium, global module, 3rd edition. Wallingford, UK: CAB International.

Dewaele. D., C. Venter, and A. H. McDonald. 1997. The peanut pod nematode, Ditylenchus africanus. Nematology Circular No.218, 6 p. Florida Department of Agriculture and Consumer Services, Division of Plant Industry, Gainesville, FL, USA.

McDonald, A.H., H. Fourie and S. Steemkamp, 2002. Quest for resistance to the peanut pod nematode. Fourth International Congress of Nematology, Tenerife.

McDonald, A.H., Loots, G.C., Fourie, H., and De Waele, D. 2005. Nematology 7:647-653.

Society of Nematologists Regulatory Committee, 2002.

Wendt, C.D., A. Swart, T.C. Vrain, and J.M. Webster. 1995. Ditylenchus africanus sp. n. from South Africa; a morphological and molecular characterization. Fundamentals of Applied Nematology 18:241-250.