Abstract:
A two-year field study was conducted at Punjab Agri
cultural University, Ludhiana,
India, to study the relative abundance of mustard/t
urnip aphid,
Lipaphis erysimi
(Kaltenbach) (Hemiptera: Aphididae) and the associa
ted resident natural enemies on 10
different rapeseed-mustard genotypes which included
:
Brassica juncea
: RH 7846, RH
9501, RK 9501, JMM 927, Purple Mutant;
B. napus
: Hyola PAC 401 (Hybrid);
B. rapa
ecotype yellow
sarson
cv. YST 151;
B. rapa
ecotype brown
sarson
cv. BSH 1;
B. carinata
:
DLSC 2 and
Eruca sativa
: T 27. The objective was to study whether indigeno
us natural
enemies can be used for biological control of musta
rd aphid. Population of turnip aphid
and different natural enemies was recorded at weekl
y intervals. There was lack of
synchronization in the peak activity of natural ene
mies with that of the aphids with a time
lag of one to two weeks depending upon the genotype
. For example, on
B. juncea
cv. RH
7846, the peak aphids’ population was recorded duri
ng the 10
th
Standard Meteorological
Week (SMW) while that of predators’ was recorded du
ring the 12
th
SMW in 2007-2008
crop season. Among the different natural enemies, c
occinellids were the most abundant
with grubs being dominant in the initial phase of p
opulation development and adults in
the later one. There is a need to conserve the resi
dent natural enemies in mustard
ecosystem for effective early season suppression of
the aphid population or release them
early in the season to suppress aphid population in
lag phase of its development.
Keywords: A
groecosystem, Ecology, Mustard aphid, Parasitoid, P
redator.
