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Development of Resistance in European Red
Mite Panonychus ulmi (Koch.) to Commonly
Used Pesticides in Kashmir
Asma Sherwani
Prof. Farooq A. Zaki
Ph.D
2009
European Red Mite, Panonychus ulmi,
Fenazaquin, Resistance, Rapd-PCR-analysis,
Kashmir
ABSTRACT
Dose mortality response in adults of European red mite Panonychus ulmi (Koch) to
various pesticides, viz., fenazaquin, dimethoate, endosulfan, chlorpyrifos and ethion and
development of resistance populations to recurrent application of fenazaquin were studied in the
Division of Entomology, SKUAST-K, Shalimar during the year 2007 and 2008, and genetic
variation analyzed by randomly amplified polymorphic DNA polymerase chain reaction (RAPDPCR) technique of the selected populations were carried out at the Insect Molecular Biology
Laboratory, Department of Entomology, PAU Ludhiana (Pb).
The findings of the investigation revealed that P. ulmi at different locations in Kashmir
valley responded differently to different pesticides used. For fenazaquin the highest LC50 values
of 0.0041 per cent and resistance factor of 6.54 were recorded in Mattan (District Anantnag)
while as the lowest LC50 value of 0.0010 and resistance factor of 1.60 was recorded in Merihama
(District Anantnag) and Rajpura (District Shopian) respectively. The LC 50 value of the
susceptible population was worked out to be 0.0006277 per cent. In case of dimethoate the
highest LC50 value of 0.029 per cent and resistance factor of 11.47 were observed in Kunil
(District Kupwara) while the lowest LC50 value of 0.014 per cent and resistance factor of 5.54
were observed in Wagoora (District Baramulla) and Kellam (District Shopian) respectively.
While as the LC50 value of the susceptible population were recorded as 0.002528 per cent.
Similarly, for endosulfan the highest LC50 value of 0.061 per cent and resistance factor of 2.45
were observed in Mattan (District Anantnag) and Wagoora (District Baramulla) respectively.
However, the lowest LC50 value of 0.027 per cent and resistance factor of 1.08 observed in
Rajpura (District Shopian). The LC50 value of the susceptible population were worked out to be
0.02486 per cent. For chlorpyrifos the highest LC50 value of 0.022 per cent and resistance factor
of 2.97 were recorded in Achabal (District Anantnag). While as the lowest LC50 value of 0.008
per cent and resistance factor of 1.19 were obtained in Bonkoot (District Bandipora) and
Malangpora(District Pulwama) respectively. Similarly the LC50 value of the susceptible
population was recorded as 0.006728 per cent. However in case of ethion the highest LC50 value
of 0.057 per cent and resistance factor of 2.83 were obtained in Zakura (District Srinagar) while
as the lowest LC50 value of 0.025 per cent and resistance factor of 1.24 were recorded in Achabal
(District Baramulla), and the LC50 value of the susceptible population was worked out to be
0.02016 per cent.
Development of resistance in eight generations of P. ulmi was exhibited when the
different generations were exposed to recurrent selection pressure with fenazaquin. When 1st
generation was exposed to selection pressure of 0.001 per cent it resulted in no resistance.
However, when the 8th generation was exposed to selection pressure of 0.004 per cent, it resulted
in 15-fold resistance. This increase in resistance could be attributed to the recurrent selection
pressure which may have led to reorganization of genes of the resistant individuals in P. ulmi
populations. In this study the genetic variations in P. ulmi populations bred through selection
pressure with fenazaquin were analyzed using RAPD-PCR. The comparative RAPD profile with
five primers viz., OPA-01, OPF-04, OPF-07, OPR-07 and OPL-08 led to the identification of
many polymorphic DNA bands that were amplified in selected population individuals and were
absent in susceptible population. This implied that selection pressure of fenazaquin resulted in
numerous genetic changes in populations of P.ulmi which could be attributed to resistance
development. Resistance factor of 15.0 obtained in 8th generation was found to be associated
with 54 per cent genetic similarity as compared to susceptible population which resulted in 95
per cent genetic similarity in generation 1st. These alterations in P. ulmi DNA could be related to
unknown genes responsible for imparting resistance of selected populations of P. ulmi.
Genetic variation amongst the eleven P. ulmi populations collected from different
locations of Valley, and subjected to bioassay to various pesticides were also investigated by
RAPD-PCR. The comparative RAPD profile with two primers, viz., OPR-07 and OPL-08
showed high level of genetic variation amongst all the eleven populations evaluated. The genetic
similarity in the eleven populations evaluated against endosulfan was computed to be 100 per
cent at Shalimar, Zakura and Kunil but it was 55.0 per cent when all the populations were
compared with Wagoora population, rest of the population lie in between. Similarly the genetic
relatedness of the eleven populations evaluated against dimethoate was computed to be 95.0 per
cent at Mattan and Zakura but it was 67.5 per cent when Merihama and Shalimar populations
were compared with Wagoora, Malangpora, Kunil, Rajpora and Achabal populations. Whileas
Mattan and Zakura populations showed genetic similarity of 77 per cent when compared with
Kupwara population. Genetic relatedness of the eleven population evaluated against fenazaquin
was recorded to be 100.0 per cent at Shalimar, Zakura, Rajpura and Malangpora and it was 62.6
per cent when the populations from Achabal and Merihama were compared with all other
populations. The genetic similarity of the eleven populations evaluated against ethion was
computed to be 100.00 per cent at Shalimar, Kunil, Madar, and Malangpora and lowest of 63.0
per cent when all the populations were compared with Merihama population. While as the eleven
populations evaluated against chlorpyrifos for genetic relatedness was evaluated to be 100.00 per
cent at Wagoora, Kupwara, Mattan Shalimar, Merihama and Rajpora but it was 66.8 per cent
when all the populations were compared with Wagoora and Kupwara populations. Highest
amount of genetic similarity was observed in populations evaluated against endosulfan while as
lowest amount of genetic similarity was registered in populations evaluated against dimethoate.