Submitted to: Journal of Agricultural and Urban Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 10, 1996
Publication Date: N/A
Interpretive Summary: The three methods used in the U.S. Tick Eradication Program for applying acaricide to livestock are immersion in a dipping vat, treatment in a spray-dip machine, or treatment with a power sprayer. Unfortunately, there are no data to prove which of these methods is the most effective for applying an efficacious dose of an acaricide. Because the objective of the eeradication program is the elimination of cattle ticks as quickly as possible after an outbreak is detected, a comparison of the effectiveness and limitations of available treatment methods is useful. Results of the experiment showed that while all three methods of acaricide application (dipping vat, spray-dip, a power spray) were highly effective, only the dipping vat method provided complete elimination of reproduction by the ticks in the shortest period of time. The offspring from the small numbers of engorged females that survived after being subjected to treatment with spray-dip and power spray equipment could compromise the efforts of a tick eradication program.
Technical Abstract: Effectiveness of coumaphos applied by 3 different treatment methods (dipping vat, spray-dip, and power spray) to cattle infested with all parasitic stages (adult, nymph, and larva) of Boophilus microplus (Canestrini) was studied. Both tick numbers and index of reproduction (IR) of females from untreated animals were higher, regardless of the developmental stage or method of treatment, indicating that the acaricide had a dramatic adverse effect on ticks. Adult ticks treated in the dipping vat resulted in fewer ticks (54 ticks/animal) and a lower IR (IR = 0.0) than ticks subjected to spray-dip (146 ticks/animal; IR = 118,253) or power spray (199 ticks/animal; IR = 289,198). Results from ticks in the nymphal stage of development at the time of treatment, indicated that the dipping vat method of treatment (1 tick/animal; IR = 0.0) was more effective than either spray-dip (54 ticks/animal; IR = 38,014) or power spray (96 ticks/animal; IR = 115,945). Likewise, the dipping vat method (0 ticks/animal; IR = 0.0) was more effective than spray-dip (23 ticks/animal; IR = 7,426) or power spray (57 ticks/animal; IR = 23,848) when ticks were in the larval stage at the time of treatment. Since the objective of any eradication program is to completely eliminate ticks as rapidly as possible, treatment of infested cattle in a dipping vat should be carried out whenever possible.