Risk factors contributing to tick-acaricide control failure in communal areas of the Oliver Tambo district eastern cape province, South Africa

Abstract

Application of chemical acaricides in the control of ticks has led to the problem of tick-acaricide control failure. To obtain an understanding of the possible risk factors involved in this tick-acaricide control failure, this study investigated tick control practices on communal farms in the north-eastern part of the Eastern Cape Province (ECP) of South Africa. A semi-structured questionnaire designed to document specific farm attributes and acaricide usage practices was administered at 94 communal farms from the Oliver Tambo District municipality of the ECP. Data collected indicated that the main acaricide chemicals used at plunge dips of inland and coastal areas were synthetic pyrethroid formulations. Most (75%) farmers claimed not to have noticed a significant reduction in numbers of actively feeding and growing ticks on cattle after several acaricide treatments. Based on the farmers' perceptions, leading factors that could have led to tick-acaricide control failure included: weak strength of the dip solution (76%); poor structural state of dip tanks (42%); and irregular tick control (21%). The rearing of crossbreeds of local and exotic cattle breeds, perceived weak strength of the dip solution and high frequency of acaricide treatment, were statistically associated with proportions of farms reporting tick-acaricide control failure. Furthermore, approximately 50% of farms reported at least four tick control malpractices, which could have resulted in the emergence and spread of tick-acaricide control failure. Other sub-optimal tick control practices encountered included incorrect acaricide rotation, and failure to treat all cattle in a herd. This data will inform and guide the development of management strategies for tick-acaricide control failure and resistance in communal farming areas.

Keywords: Acaricide; Application practices; Cattle production; Control failure; Tick control.

Fig. 1

Map of OR Tambo district municipality showing locations of communal farms included in the study

Fig. 2

Acaricide chemical groups used on cattle ticks on communal areas in the OR Tambo District of the Eastern Cape province of South Africa. ^# Percentages were obtained from number of farms that used an acaricide chemical group and total number of farms sampled

Fig. 3

Proportions of Inland (I) and Coastal (II) communal farms with combinations of risk factors associated with tick-acaricide control failure. A- Alleged weak strength of the dip solution; B- Irregular tick control; C- High acaricide application frequency during summer; D- Failure to treat all cattle in a herd