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Rice Brown Planthopper
either from Maharashtra region or from Orissa-west Bengal region towards
Bihar, Jharkhand, Uttar Pradesh, Haryana and Punjab. Although, the exact
reason for this is not very clear, it is probably an exploratory exercise as a part
of innate nature of this insect to move even to very far off places in search of
food wherever weather conditions are favorable. Secondly, cultivation of huge
acreage under “boro” rice might also be aiding in exploiting the migratory
nature of the insect.
Long Range Migration of South Asian Biotype of BPH:
BPH cannot survive the severe winters present in Punjab, Haryana, Uttar Pradesh,
Bihar, Jharkhand and northern parts of West Bengal from November to February as
the temperatures are near freezing point or at times towards negative side. BPH cannot
over-winter in egg stage. Further, there are no alternate hosts for BPH where it can
survive and complete its life cycle. Therefore, BPH must be migrating from southern or
eastern parts of India during the months of May-June immediately after the harvest of
rabi crop in southern or eastern states.
Southwest monsoon starts at the beginning of June every year in southern tip of India.
It takes about a month for the full monsoon winds to be active throughout the country.
The progress of south-west monsoon is all along the west coast from Kerala to Konkani
region of Maharashtra, followed by Tamil Nadu and Karnataka, then Andhra Pradesh
and Orissa, but cannot cross the Vindhya and Sathpura mountain ranges present in
Madhya Pradesh. Simultaneously, south-west monsoon also starts in Bay of Bengal
and moves from coastal areas of West Bengal and Bangladesh and proceeds in north-
westerly direction due to its inability to cross Himalayas. Both the halves of South-
West Monsoon meet somewhere in areas of Chattisgarh -Jarkhand-Bihar border and
move in north-westerly direction. Thus, the movement of south-west monsoon winds is
northwesterly in direction from West Bengal through Jharkhand, Bihar, Uttar Pradesh
and then finally reaching Haryana and Punjab.
From 1972, up to early 1990s, WBPH was the major problem in Punjab and Haryana
probably because the macropterous adults of WBPH could move along the first south-
west monsoon winds moving from West Bengal towards Punjab and Haryana in a
north-westerly direction. It is well known that when compared to BPH, WBPH is more
migratory and does not settle even if suitable host plant, viz. rice crop is available. It
