Yam lesion nematode (008)

Pacific Pests, Pathogens, Weeds & Pesticides - Online edition

Pacific Pests, Pathogens, Weeds & Pesticides

Yam lesion nematode (008)

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Photo 1. Pratylenchus coffeae in yam causes a shallow rot beneath the skin; the importance of the rot is not only the loss of flesh for eating, it is also the loss of planting material. Yams infected with dry rot do not sprout or, if they do, the cutting will be infested with nematodes which will attack the roots when the sets are planted.

Photo 2. Pratylenchus coffeae in yam causes a shallow rot beneath the skin.

Photo 3. The head of Pratylenchus sp. showing the hollow spear or stylet (arrow), which is used to puncture cells in order to move through the roots, as well as to feed on their contents.

Summary

Worldwide distribution. On yam, banana, and many other crops and weeds. Note, the burrowing nematode, Radopholus similis, causes a similar disease on banana (see Fact Sheet no. 257). An important disease.
Eggs are laid in roots or nearby in soil; young larvae, and adults, tunnel through roots and tubers using a hollow spear to suck cell contents. Roots are killed.
Spread is in ground water, and infested tubers and setts used for planting.
Cultural control: non-host break crop (e.g., cassava, sweetpotato, ground legumes – Mucuna or Pueraria; discard sets with rot, or cut out with knives wiped in bleach; alternatively, treat yam setts in hot water (51°C for 10 minutes) or, for banana sets, (53°C for 20 mins.); avoid storing tubers with rots, and if seen remove; 3-year crop rotation.
Chemical control: none recommended.

Common Name

Dry rot of yam, brown dry rot, banana root nematode, toppling of banana

Scientific Name

Pratylenchus coffeae

Photo 4. Pratylenchus coffeae inside a root.

Photo 5. Banana roots with purple/black discolouration caused by Pratylenchus coffeae. Infected roots rot and plants are weak and yields are small.

Photo 6. "Toppling" is a common symptom on banana when roots are attacked by Pratylenchus coffeae. Note this banana has fallen over before the fruits have matured; a sign of nematode attack. A similar symptom occurs when bananas are infected by the nematode Radopholus similis.

Diagram. Life cycle of Pratylenchus coffeae.

AUTHORS Helen Tsatsia & Grahame Jackson
Information (and Diagram) from Davis EL, MacGuidwin AE (2005) Lesion nematode disease. The Plant Health Instructor. DOI: 10.1094/PHI-I-2000-1030-02; and from Hauser S, Coyne D (2010) A hot bath cleans all: Boiling water treatment of banana and plantain. Technical Innovation Brief. No. 8. (https://www.ctc-n.org/sites/www.ctc-n.org/files/resources/4ea6bfcd-2658-4dac-bf31-03861661b3dc.pdf). Photo 1 V Vanstone Pratylenchus penetrans: a horticulturally significant root lesion nematode. Department of Agriculture and Food, Government of Western Australia. Photo 4 John Bridge, CABI, UK.

Produced with support from the Australian Centre for International Agricultural Research under project PC/2010/090: Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production, implemented by the University of Queensland and the Secretariat of the Pacific Community.

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