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This study examined the pattern of resistance to widely applied synthetic pyrethroids, i.e., cypermethrin and deltamethrin, against larvae of Rhipicephalus microplus ticks sampled from Marathwada region in Maharashtra, India. The study also examined the role of α- and β-esterases and glutathione-S-transferase (GST) in resistance development. All eight R. microplus isolates tested were resistant to deltamethrin (RL IV), having RR 50 values from 6.88 to 131.26. LPT analysis exhibited the resistance level II deltamethrin resistance in Beed and Hingoli, III in Dharashiv, and IV in Sambhajinagar, Parbhani, Latur, Jalna, and Nanded isolates. The LIT analysis showed that Dharashiv field isolates had the lowest LC 50 value of 229.09 ppm against cypermethrin, while Sambhajinagar field isolates had the highest at 489.78 ppm. The RR 50 ranged from 1145.45 to 2448.9. Seven isolates were level I resistant to cypermethrin while the Jalna isolate was level II resistant. In larvae treated with deltamethrin and cypermethrin, the activity of α- and β-esterase enzymes increased significantly compared to control groups. The enzyme ratios in treated larvae ranged from 0.7533 to 1.7023 for α-esterase and 0.7434 to 3.2054 for β-esterase. The Hingoli isolate treated with cypermethrin exhibited the highest α-esterase activity (903.261), whereas Sambhajinagar isolate had the highest GST enzyme ratio (2.8224) after deltamethrin exposure. When exposed to cypermethrin, the Hingoli isolate showed the highest GST enzyme ratio, 2.0832. The present study provides the current resistance status in tick populations from Marathwada region indicating deltamethrin and cypermethrin to be ineffective for tick control. The results also suggest that SP compounds should be regulated in this region and alternative control strategies should be introduced., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

In the present study, the crude aqueous and chloroform extracts of Annona squamosa was tested for its in-vitro acaricidal efficacy against Rhipicephalus microplus ticks. Concentrations of 2.5%, 5%, 7.5%, 10% and 12.5% were tested against adult ticks whereas 0.312%, 0.625%, 1.25% and 2.5% were tested against larvae. No significant mortality and effect on oviposition was observed using aqueous extract, however, chloroform extract showed strong activity against both viz. adults and larvae. The highest adult mortality was observed at 12.5% concentration and determined LC50 and LC90 values were 5.24% and 14.12% respectively. A dose dependent reduction in egg laying capacity of treated female was observed in all concentrations compared to control group. The recorded mean mortality of larvae was 13.45 ± 0.73, 71.04 ± 1.10, 98.28 ± 0.39 and 100 ± 0.00 observed at 0, 0.312%, 0.625%, 1.25% and 2.5% of concentrations respectively. [ABSTRACT FROM AUTHOR]

The aqueous and chloroform extracts obtained from leaves of Adhatoda vasica were evaluated for acaricidal activity against engorged females of Rhipicephalus microplus and their larvae. No significant mortality of adult ticks was observed in the tested concentration of aqueous extract except at 80%. Whereas, chloroform extract showed a dosedependent increase in adult mortality, and LC50 and LC90 values were determined as 10.47% and 11.74%, respectively. A significant difference in egg hatching of laid eggs was observed at all concentrations tested and 98.55% inhibition of hatching was observed at 12.5% concentration. Dose-dependent larval mortality was observed in larval immersion test with various concentrations of chloroform extract with LC 50 and LC 90 values of 0.51%, and 1.09%, respectively. The results indicate that the chloroform extract of Adhatoda vasica could have very good in vitro acaricidal activities on adult and larval stages of Rhipicephalus microplus ticks. [ABSTRACT FROM AUTHOR]

A study was conducted to investigate the tick infestation on cattle in the plain region of Chhattisgarh state. During the period of study, 832 ticks of 47 animals were examined for the different tick species. The most prominently infested ixodid tick belonged to Hyalomma anatolicum (68.38%) followed by Rhipicephalus microplus (30.40%).The females showed higher infestation than males. A single tick species infestation pattern was observed in 17 animals while 30 animals were infested by both tick species. Single species infestation of H. anatolicum was encountered in 15 animals while R. microplus was observed in 2 animals. The intensity of tick infestation on each animal varied from 6 to 65 ticks per animal at different locations. [ABSTRACT FROM AUTHOR]