Alfalfa Mosaic Virus
Aphid-Transmitted Bacilliform Virus
World Vegetable Center
The foliage has a distinct bright yellow to white mosaic
that sometimes causes large areas of interveinal leaf
tissue to be bleached in appearance. Chlorotic line
patterns and veinal necrosis also may occur. Generally,
the leaves are not distorted in shape. If infected when
young, the plants may be stunted and their fruit will be
Conditions for Disease Development
Alfalfa mosaic virus (AMV) is found most commonly in
pepper crops that have been planted near alfalfa, clover
or other legumes. It is generally considered to be a
minor threat to pepper production.
Transmission by seed is the primary means of
establishment of the virus while aphid transmission is
more important for the subsequent spread in field
plantings. AMV is transmitted by many species of
aphids including the green peach aphid, Myzus
persicae. The aphid can acquire the virus by feeding on
an infected plant for less than a minute and can transmit
Bright yellow to white mosaic patterns on interveinal regions of leaves;
sometimes large areas may be affected
How to Identify Alfalfa Mosaic Virus
Written by Ray Cerkauskas, Visiting Scientist from Agriculture and Agri-Food Canada. Edited by Tom Kalb. Photos by J.M. Poulos, V.
Stravato, J.C. Waterson and R.I. Muhyi. Published by AVRDC – The World Vegetable Center; P.O. Box 42, Shanhua; Taiwan 741; ROC
tel: (886-6) 583-7801; fax: (886-6) 583-0009; email: firstname.lastname@example.org; www: www.avrdc.org
Bleaching of leaves
it as quickly, but the aphid actually retains the virus for
only a short period of time. The virus is also readily
transmitted mechanically and by grafting.
Pepper varieties resistant to AMV are not available.
Various control measures are required because
AMV is transmitted by seed, aphids, and mechanically.
Control measures must take into account the disease’s
wide host range (alfalfa, pepper, tomato, tobacco, potato,
clover, many cucurbits and beans, and sever