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MUNGBEAN YELLOW MOSAIC VIRUS, PULSES - INDIA (PUNJAB)

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Pulse crops such as urdbean, mungbean, and soybean in Punjab have 

come under attack of whiteflies, an insect pest. The attack has been 

witnessed in all the pulse-growing areas of the state, a Punjab 

Agricultural University (PAU) press release stated today [26 Aug 

2007]. This insect has appeared in epidemic form due to the hot 

weather conditions coupled with dry monsoon spell prevailing in the 

state over the last few weeks. Such weather conditions are extremely 

conducive for the rapid multiplication of the pest.



According to Dr N S Buttar, Head, Department of Entomology, PAU 

[Punjab Agricultural University], whitefly feeds on the leaves of the 

plants by sucking the cell sap and excretes honey dew on the plants, 

on which the growth of sooty mould takes place, resulting in the 

blackening of leaves and decreases in the normal photosynthesis. In 

case of severe attack, there is total blackening of the crop, 

resulting in drying of leaves and ultimately, total crop failure. 

Whitefly is also a vector of serious viral disease -- mungbean yellow 

mosaic --, which is a limiting factor in the successful cultivation 

of these crops.



Dr Buttar has advised the farmers not to get panicky and to spray the 

crop with the recommended insecticides.



--

J. Allan Dodds





[_Mungbean yellow mosaic virus_ (MYMV; genus _Begomovirus_, family 

_Geminiviridae_) is endemic to South Asia. A number of strains have 

been isolated from different hosts and locations (India, Thailand, 

Philippines).



_Mungbean yellow mosaic India virus_ (MYMIV) has now been classified 

as a distinct species. It is the most serious problem of mungbean in 

the Indian subcontinent (India, Pakistan, Nepal, Bangladesh) and also 

affects other leguminous crops such as soybean, cowpea, pidgeonpea, 

and black gram. Infected plants become chlorotic and stunted, and 

yield losses of up to 100 percent have been reported in severely 

affected crops. MYMIV is transmitted by whiteflies (_Bemisia tabaci_) 

in a non-persistent manner, meaning that vector insects remain 

infective for a period of time after acquisition of the virus. MYMIV 

is not transmitted by mechanical inoculation, seed, or pollen. 

Disease management includes vector control (insecticides, weed 

control) and the use of resistant host varieties.



Interaction between MYMIV and a satellite DNA has been reported 

resulting in even more severe symptoms than infection by the virus 

alone. _Begomovirus_-satellite disease complexes have been found to 

cause economically important diseases in a range of crops and pose a 

serious threat to tropical and sub- tropical agriculture worldwide.



It is not stated in this report whether MYMIV symptoms have already 

been observed in the region. Since the virus is rife in northern 

India, potential sources of inoculum for the vector insects may be 

expected to be available, and dispersal (for example by wind, plant 

material, human movement) of insects carrying the virus would be 

likely. Once a local source of MYMIV is available, spread throughout 

the regional crops will be very fast given the large numbers of 

vector insects present.



Maps



Pictures





2004

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Severe leaf curl disease, cowpea - India 20041119.3098]

...................................dha/mj/dk