BIOSYSTEMATICS OF LEAFHOPPERS IN MANGO ORCHARDS AND THEIR MANAGEMENT WITH CERTAIN NEWER INSECTICIDES
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Date
2010
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ACHARYA N.G. RANGA AGRICULTURAL UNIVERSITY, RAJENDRANAGAR, HYDERABAD
Abstract
The studies on “Bio-systematics of leafhoppers in mango orchards and
their management with certain newer insecticides” was undertaken during
2006-08. The taxonomic studies on the leafhopper fauna associated with
mango orchards in Andhra Pradesh were carried out in the department of
Entomology, S.V. Agricultural College, Tirupati after collection of leafhoppers
from different mango orchards of various places in Andhra Pradesh. The field
experiments regarding the studies on the influence of abiotic and biotic factors
with population buildup of leafhoppers on mango crop, incidence of
leafhoppers on different mango varieties and evaluation of different spray
schedules of insecticides in the management of leafhoppers were undertaken in
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the existing mango orchards at Regional Horticultural Research Station,
A.P. Horticultural University, Anantarajupet of Kadapa District.
Four leafhoppers viz., Amritodus atkinsoni (Lethierry), Amritodus
brevistylus (Viraktamath), Idioscopus nagpurensis (Pruthi) and Idioscopus
niveosparsus (Lethierry) were identified, described and illustrated male
genitalia structures. A key for distinguishing all these species was provided.
The leafhopper, Amritodus brevistylus (Viraktamath) is reported for the first
time and hence it is a new record on mango from Andhra Pradesh. Among the
above four species recorded from Andhra Pradesh, A. atkinsoni was a
dominant species (62.80%) followed by I. niveosparsus (31.70%) and the
remaining two species I. nagpurensis (5.3%) and A. brivistylus (0.02%) were
less abundant. The natural enemies associated with mango leafhoppers
recorded were lysomanid spider, Telamonia sikkimensis (Tikader), coccinellid
predators, Cheilomenes sexmaculata (Fabricius) and Anegleis cardoni (Weise)
and chrysopid, Chrysopa lacciperda Kimmins.
The leafhopper population increased gradually from the first week of
September and reached to a peak during second to fourth week of February and
thereafter the population declined gradually in the first week of May. The
correlation between the leafhopper population, minimum temperature and
evening relative humidity was negative and significant, whereas correlation
with maximum temperature, morning relative humidity and rainfall were also
negative but not significant. The relationship between leafhoppers, coccinellid
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predators and spiders was positive and significant. The mango varieties viz.,
Mulgoa, Neelum, Totapuri, Banganpalli and Rumani were observed to be
relatively less by mango leafhoppers.
Among all the insecticidal treatments tried, thiamethoxam 25 WG @
0.005% given in three sprayings gave significantly highest percentage
reduction of leafhoppers and highest yield including highest cost-benefit ratio
(1: 16). Chlorfenapyr 10 SC @ 0.01% sprayed thrice and the treatment with
three sprayings where in first spraying with chlorfenapyr 10 SC @ 0.01%,
second spraying with thiamethoxam 25 WG @ 0.005% and third spray with
diafenthiuron @ 0.07% were also found good next in the order against mango
leafhoppers, but with low cost benefit ratio (1:4.66 to 4.86). The conventional
insecticides of monocrotophos 36 SC @ 0.072%, imidacloprid 17.8 SL @
0.006% and carbaryl 50 WP @ 0.15% given in first, second and third
sprayings also recorded comparatively high cost benefit ratio (1:6.80 to 8.87)
and hence this spray schedule can also be recommended against mango
leafhoppers.
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Keywords
BIOSYSTEMATICS, LEAFHOPPERS, MANGO, ORCHARDS, MANAGEMENT,NEWER, INSECTICIDES