boophilus microplus resistance in brazil and testing of a new formulation of amitraz. campo grande,...
TRANSCRIPT
Boophilus microplus resistance in Brazil
and testing of a new formulation of amitraz.
Campo Grande, MSJoão R. Martins.
IPVDF - Brazil [email protected]
CHRONOLOGY OF CHRONOLOGY OF ACARICIDE RESISTANCE ACARICIDE RESISTANCE
CHRONOLOGY OF CHRONOLOGY OF ACARICIDE RESISTANCE ACARICIDE RESISTANCE
Arsenical 1948Organochloride 1952Organophosphates 1974Pyretroids 1989Amidines 1994Mixtures OP/PS 1998Ivermectines * 2001
activeIngredient
*1st report
The cattle tick The cattle tick Boophilus microplusBoophilus microplus
Economic ImportanceEconomic Importance
*Costs with acaricides*Costs with acaricides
*Instalações*Instalações
*Handling, labour*Handling, labour
*Transmition of babesiosis/anaplasmosis*Transmition of babesiosis/anaplasmosis
*US$ 1 b (1983) & US$ 2 b (2002)*US$ 1 b (1983) & US$ 2 b (2002)
Situation on acaricide resistance in Brazil
• Several reports (especially summaries in Congress)• Main reports dealing with OP, SP, Amitraz and
mixtures OP/SP all over the country• Few cases with LMs (RS and SP)• No case of fluazuron and fipronil resistance was
published • Despite reports, many farms keep using these
a.i. (aspersion)
ADULT IMMERSION TESTS RESULTS
2005
Amitraz Mixtures Pyretroids + Phosphates
Suscetibles 12 (41,3%) 26 (92,8%)
Resistants 17 (58,6%) 02 (7,1%)
Total 29 28
Resistance to
Amitraz in
2005
FirstReport inRS: 1994
Porto Alegra LC99 = 0.028 (0.020-0.064)
2X LC99
Plots of amitraz resistant and amitraz susceptibleB. microplus from Brazil (Dec 2002 - Apr 2003)
Concentration (Amitraz)
0.0001 0.001 0.01 0.1 1 10
Mo
rta
lity (
%)
1
2
5
10
20
30
405060
70
80
90
95
98
99
São Gabriel (Susceptible)Porto Alegre (Susceptible)Palma Rincão São Borja
Toxicological behavior of susceptibles and resistents strains of B. microplus to amitraz.
Amitraz granulated 75%
Physical, ChemicalBiological evaluation
Monthly Control of pH, concentration and biological efficacy
45 days after :
>Decrease pH, but keep acting
“in vitro”
Amitraz granulated 75%
-ph decreases to 8.0 – 8,5 in 30 days
-concentration remains above 150 ppm up 2 months
-sedimentation occurs rapidly
- “in vitro” efficacy up to 4 months
-after 6 months, amitraz was below 30 ppm
Average of adult ticks treated with Amitraz Granulated 75% in a stall test
0
50
100
150
200
250
300
350
400
450
-2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
Days after treatment
Ave
rage
of
adu
lt t
ick
s
control
treated�
Treatment
Amitraz wp 75%: “in vitro” & field tests
Coleta de calda do banheiro
Banho carrapaticida por Banho carrapaticida por imersãoimersão
Instituto de Pesquisas Veterinárias Desidério Finamor Eldorado do Sul, RS.