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Plantwise Factsheets for Farmers

Management of root knot nematodes in tobacco

Meloidogyne sp.

Recognize the problem

The root knot nematode disease also known as eelworms or “mandolo” reduces yield and quality of tobacco.


Root knot nematodes are found and stay for long periods in the soil. Distribution of nematodes in the soil is irregular or patchy. Nematodes affect tobacco in the nursery and field causing roots to be swollen or have knots, and even rot. Other symptoms include yellowing, wilting, and stunting of plants. Root knots are caused by nematodes.  Nematodes cause disease in tobacco plants through injuring roots resulting in reduced intake of water and minerals from soil.  Nematodes are spread by dirty irrigation water, through contaminated implements during ploughing, and planting tobacco in infested soil.  


The best approach to manage root knot nematodes is through Integrated Pest Management (IPM) in the nursery and field as described below:
  • Follow a 4 year rotation, for example Tobacco-Maize-Groundnuts-Tobacco and include fallow in the rotation
  • Grow the following resistant / tolerant varieties: Burley BRK4 /Flue cured AFH1, AFH2, AFH3 and AFH4
  • Uproot and burn all tobacco leftover seedlings and stalks soon after completing harvesting
  • In the Nursery: broadcast Dazomet pesticide such as Basamid at 1.5kg for each bed of 30m2. Mix the chemical with soil by cultivating the bed using a new hoe across and along the bed 14 days before sowing. Cover with a black plastic paper. Alternatively you can use Metham sodium such as Herbifume should be drenched on the seedbed at the rate of 3 litres in 30 litres of water for a bed of 30 m2. Drench the chemical 14 days before sowing. Cover with a black plastic paper for 14 days, after which you remove the black paper and cultivate the soil to allow air in.

When using a pesticide, always wear protective clothing and follow the instructions on the product label, such as dosage, timing of application, and pre-harvest interval.

The recommendations in this factsheet are relevant to: Malawi

Authors: Chrissie Mainjeni
The Department of Agricultural Extension Services (DAES)
tel: +2651750379 email:
©CAB International. Published under a CC-BY-SA 4.0 licence.

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