In vitro acaricidal activity of Piper longum L. against amitraz resistant Rhipicephalus microplus (Acari: Ixodidae).

The cattle tick, Rhipicephalus microplus Canestrini (Acari: Ixodidae) is one of the most important tick species severely affecting health and causes huge losses to dairy industry. Chemical acaricides are mainly applied for tick control but development of resistance, environmental pollution and contamination of milk and meat products with residues has led to exploration alternative eco-friendly tick control strategies. The dried fruits of Piper longum L. (Indian long pepper, Thippali or Pippali) generally used as flavoring agent have also been shown to have insecticidal property. Different concentrations (0.625%-10%) of alcoholic and aqueous extracts of Piper longum L. were prepared and evaluated for acaricidal activity against amitraz resistant R. microplus adult and larval stages. Against larval stages a dose-dependent mortality response was recorded for both extracts and higher acaricidal property was exhibited by the alcoholic extract with LC50 and LC95 (95% CL) values of 0.488% (0.48-0.49) and 1.39% (1.35-1.44), respectively. Similarly, against adult engorged females, ethanolic extract showed higher acaricidal property with LC50 and LC95 (95% CL) values of 4.67% (4.61-4.74) and 12.38% (12.05-12.73), respectively. Significant (p < 0.05) reduction was recorded in reproductive index of ticks treated and but no effect on hatchability of eggs was recorded in treated groups. The present study establishes acaricidal activity of P. longum fruit extracts against both larval and adult stages of amitraz resistant population of cattle tick.

In vitro assessment of the acaricidal activity of Piper longum, Piper nigrum, and Zingiber officinale extracts against Hyalomma anatolicum ticks.

Ticks and tick-borne diseases are a major constraint for the sustainable cattle industry in the tropical and subtropical regions including the Indian subcontinent. The development of resistance to most of the commonly used acaricides leads to an attempt to screen plant extracts and their combinations for their possible acaricidal activity to develop an eco-friendly tick control alternative. An alcoholic and various aqueous extracts of Piper longum, Piper nigrum and Zingiber officinale and their combinations were evaluated for acaricidal activity against the three-host ixodid tick, Hyalomma anatolicum by larval immersion test using 14-21 days old unfed larvae. The efficacy was assessed by measuring larval mortality (%) and the lethal concentrations for 50% (LC50) and 95% (LC95) with their 95% confidence limits (CL) values were estimated by applying regression equation analysis to the probit transformed data of mortality. A concentration-dependent mortality response was recorded in all extracts prepared from seeds of P. longum and P. nigrum and their combinations. The highest acaricidal property was exhibited by the alcoholic extract of P. longum seeds with the minimum LC50 and LC95 (95% CL) values of 0.071% (0.07-0.072) and 0.135% (0.13-0.14), respectively, followed by alcoholic combinations. Interestingly, no acaricidal activity was recorded in extracts prepared from the rhizome of Z. officinale. The results indicated that the ethanolic extracts of P. longum and P. nigrum and their combinations can be used effectively for tick control in an integrated format.