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 setts are planted.
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.
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.
Dry rot of yam, brown dry rot, banana root nematode, toppling of banana
AUTHORS Helen Tsatsia & Grahame Jackson
Information (and Diagram) from Davis EL, MacGuidwin AE (2000) Lesion nematode disease. The Plant Health Instructor. DOI: 10.1094/PHI-I-2000-1030-02. Updated 2005; and from Hauser S, Coyne D (2010) A hot bath cleans all: Boiling water treatment of banana and plantain. (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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