A new disease of onion cased by Aphelenchoides besseyi is reported from Sri Lanka. Symptoms are similar to those of the white tip disease of rice, caused by the same nematode: distortion, twisting of stems and discoloration of the leaf apical portion. Chemical treatments increased quantitative and qualitative yields of onion bulbs. Correlations between final nematode populations in the stem tissues with percentage of plants with symptoms or with yields indicate that A. besseyi is a major factor in the disease.
