This document summarizes three common diseases that affect beans: anthracnose, rust, and yellow mosaic. Anthracnose causes sunken black spots on leaves, stems, and pods and can kill seedlings. It is caused by the fungus Colletotrichum lindemuthianum. Rust appears as small reddish-brown pustules on the lower leaf surface and is caused by the fungus Uromyces fabae. Yellow mosaic causes yellow mottling and stunting in beans and is transmitted by the whitefly Bemisia tabaci. Management of these diseases involves crop rotation, resistant varieties, and fungicide or insecticide applications to control the pathogens and vectors.

1. Diseases of Bean
HPP 5311
Diseases of vegetables, ornamentals
and spice crops.

2. Anthracnose
• The disease is more severe in temperate and subtropical
mountaneous regions of the world with cool and wet climate.
• Colletotrichum lindemuthianum

3. Symptoms
• All the above ground parts are affected at any stage of crop
growth. However, the characteristic symptoms appear on
pods.
• On cotyledons spots are sunken dark brown or black with pink
spore mass.
• Seedling infection results in collapse of seedling.
• Spots on leaves appear on lower side and are black. Later
these may also appear on upper surface. When the infection
is severe, the affected plants wither off.

4. • Black, sunken, circular spots of varying sizes appear on pods
with bright red, yellow or orange margins.
• The centre of these spots later turns grey or pink due to
sporulation of the pathogen. The border of these spots
appear raised.

5. Pathogen
• The mycelium is branched, septate and hyaline at first
becoming dark with age.
• The acervulus contains a layer of 3 to 50 conidiophores
depending on the size of lesion.
• Conidia are hyaline, cylindrical having rounded ends or
somewhat pointed at one end and often bear a clear vacuole
like body near the centre.
• The teliomorph of the pathogen has been identified as
Glomerella cingulata (Ston.) Splaud & Schrenk

6. Survival and spread

7. Management
• Follow 2-3 years of crop rotation with non-leguminous crops.
• Use disease free seed and treat them with carbendazim or
benomyl (0.2%).
• Resistant cutivars/ lines like KRC 1, KRC 17, EC 42960 and EC
57080 have been identified as resistant to this pathogen.
• In field, the spread of the disease can be limited by
application of fungicides like mancozeb (0.25%) or
combination of mancozeb (0.25%) and carbendazim (0.05%)
or tricyclazole (0.03%) and repeat at 10 -14 days interval.

8. Rust
• Uromyces fabae

9. Symptoms
• The symptoms mostly appear on leaves, though often they
are found on petiole and stem of some hosts.
• The rust pustules appear on either sides but more common
on lower surface.
• The Uredosori are minute, roundish, slightly raised and
reddish brown coloured. These contain rust spores and
appear in groups.

10. • Later in the season with the formation of teliospores, the sori
turn dark brown or black.
• Diseased leaves may wither or fall off under severe infection

11. Pathogen
• The urediniospores are brownish, globoid or ellipsoid, one
celled and echinulate.
• Spore wall is golden brown 1-1.5 μm thick having two
equatorial pores.
• Teliospores are dark brown coloured, elliptical and ovate,
pedicillate, smooth walled, single celled with warty papillae at
the top.

12. Disease cycle and epidemiology
• P.I: Survives through teliospores in cooler regions and on
collateral hosts
• S.I: Wind borne Uredospores
• Host range: French beans, green gram, black gram and
cowpea.
• Areas having high humidity and temperature upto 24⁰C are
most suitable for disease development.
• Urediniospores germinate optimally at 15-24⁰C while for
teliospores germination, 10-15⁰C is optimum.

13. Management
• Collect and destroy the infected plant debris.
• Follow long crop rotations.
• With the initiation of the disease, spray the crop with
mancozeb (0.25%) or hexaconazole (0.1%) or difenoconazole
(0.05%) or combination of mancozeb (0.25%) and
hexaconazole (0.05%) and repeat at 10 days interval.

14. Yellow mosaic
• Bean Yellow Mosaic Virus, Mungbean yellow virus or
Phaseolus virus-2 (ss DNA virus)

15. Symptoms
• Bright yellow patches appear on leaves.
Yellow areas alternate with dark green areas
of the leaf blade.
• Younger leaves show more severe mottling
and chlorosis.
• Leaves completely turn yellow and gradually
becomes necrotic
• Plants are stunted and flower and pod set is
reduced
• Pod formation is reduced and if produced,
they are deformed having shrivelled and
undersized seeds

16. Survival and spread
• P.I: Collateral hosts
• S.I: Whitefly, Bemisia tabaci
• Not transmitted by sap, seed and pollen
• Host range: French bean, Soybean, Red gram, Xanthium
strumarum, Eclipta alba, etc.

17. Management
• Remove collateral hosts and destroy
• Use resistant varieties
• Spray metasystox@0.1% for vector control