Rev 11/19/2019
Reported median body size for this species (Length mm; width micrometers; weight micrograms) - Click:
Common in peanut growing areas of the Republic of South Africa and only reported from that area.
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:
Therefore management strategies that maintain or enhance yield and minimize blemish of kernels are of primary importance.
(McDonald et al., 2005)
D. africanus has fungivorous habits and can be reared in fungal cultures (Aspergillus sp., Botrytis sp., etc.)
Peanut (Arachis hypogaea) is the principal host. Other agronomic crops and weeds can be infected without showing any symptoms or damage.
Unlike D. destructor, D. africanus does not infect potato.
Ecophysiological 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:
(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.
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:
Partial resistance has been developed from local African germplasm, elite breeding lines and hybrids. The resistance is overcome at high nematode infestation.
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.