INSECTICIDAL ACTIVITY OF AQUA RESIGEN ULV IN AND OUT – DOOR APPLICATION IN PASTEUR INSTITUTE AND NHA BE district, HCMC

 

Tran Khanh Tien, Tran Huu Hoang, et al.

Pasteur Institute of HCM City

 

Abstract

Aqua Resigen is an insecticide belonging to Pyrethroid group, composed of 2 chemicals: S-Bioallethrin + Permethrine and synersised by Piperonyl Butoxide to increase the insecticidal activity and to restrict the Permethrine resistance of mosquitoes due to long-term application of Permethrine on a large scale.

Aqua Resigen ULV has been sprayed in and out door to control Aedes aegypti by Fontan backpack- sprayer in the courtyard of Pasteur Institute and Nha Be district, HoChiMinh City. At dilution rate of 1+9, dosage of 500 ml/ha (0,075gr S-Bioallethrin + 5,4gr Permethrine/ha) and 1+19, dosage of 40 ml/ha (0,003gr S-Bioallethrin + 0,216gr Permethrine/ha) the results are as follows:

§         In applying out-door, the insecticidal activity is very weak because of wide space, the quantity of active ingredient is not enough to cover all the trial site. At such a dosage (500 ml/ha at dilution 1+ 9) after 1 hour of exposure the knockdown is 41,1% – 60,6% at the distance of 10, 5m far from sprayer (graph 2). After 24 hours, the death percentage is 83,9% – 93,9% at the same distance (Table 1). The further the distance is, the weaker the activity is.

§         Aqua Resigen has good activity when spraying house to house at the dosage of 500 ml/ha dilution 1+ 9, because of restricted space. After 24 hours, caged mosquito death percentage is 77,3% – 100% at the distance of 5m – 20m (Table 2). But a weaker activity is obtained on indoor resting mosquitoes. After 2 applications at the interval of 7 days, mosquito density is reduced to 89,5% and at low level for 2 weeks (table 3)

From the above-mentioned results, it is necessary to increase the dosage to 1,5 times (indoor) and to 2 times (outdoor) to kill mosquitoes, controlling DHF on a large scale.

§         In experiment, in 500ml glass beaker containing 250ml of water, death percentage of larvae is 55% – 84,4% at the distance of 10m and 5m far from swath (Table 1). But in common household water containers (jar, basin, small jar) the efficacy is not good and long lasting because of the small quantity of insecticide dissolved in a large quantity of water.

§         Aqua Resigen ULV dissolved in water has no bad smell, no irritation on skin and mucous membrane. Without using diesel as a diluent, we can reduce the spending.

Table 1: Insecticidal activity of Aqua Resigen (a) ULV outdoor application against caged Aedes aegypt. Combined results from 3 trials (12 & 16/11/1998 and 07/01/1999).

Distance

(m)

Number of

insects

(Adults/larvae)

Number of deaths after exposure

No of deaths
after 24 h

% of deaths in control group after 24 h

20 minutes

40 minutes

60 minutes

No.

%

No.

%

No.

%

No.

%

5

180/180 (b)

37

21

20,6

11,7

69

74

38,3

41,1

109

108

60,6

60

169

152

93,9

84,4

 

 

 

 

 

Adult = 1,13

Larva =1,1

10

180/180

24

4

13,3

2,2

47

38

26,1

21,1

74

56

41,1

31,1

151

99

83,9

55

20

180/180

1

0

0,6

0

4

0

2,2

0

12

2

6,7

1,1

60

10

33,3

5,6

30

180/180

1

0

0,6

0

1

0

0,6

0

1

1

0,6

0,6

35

6

19,4

3,3

40

180/180

3

0

1,7

0

3

0

1,7

0

4

0

2,2

0

20

0

11,1

0

50

180/180

0

0

0

0

1

0

0,6

0

1

0

0,6

0

8

0

4,4

0

 (a): 1 Aqua Resigen + 9 water. Dosage 500ml/ha.

 (b): 20 female mosquitoes/ cage and 20 larvae III – IV instar/ glass beaker. 3 cages and 3 glass beakers for each distance. Combination of 3 experiments.

 

Table 2: Combined insecticidal activity of Aqua Resigen (a) ULV indoor application against caged Aedes aegypti, from 2 trials in Nha Be, HCMC (22/12 and 29/12/1998).

Trial group

No. of

Adults/
Larvae

In test

Number of deaths after exposure

Number of deaths

After 24 hours

20 minutes

40 minutes

60 minutes

Mosquitoes

Larvae

Mosquitoes

Larvae

Mosquitoes

Larvae

Mosquitoes

Larvae

SL

%

SL

%

SL

%

SL

%

SL

%

SL

%

SL

%

SL

%

 5m

10m

20m

30m

150/150 (b)

150/150

150/150

150/150

114

50

42

1

76

33,3

28

0,7

23

1

0

0

15,3

0,7

0

0

145

73

56

4

96,7

48,7

37,3

2,7

98

34

10

0

65,3

22,7

6,7

0

149

101

73

11

99,3

67,3

48,7

7,3

121

57

17

0

80,7

38

11,3

0

150

146

116

66

100

97,3

77,3

44

149

133

55

27

99,3

88,7

36,7

18

Control group

200/200

0

 

0

 

0

 

0

 

0

 

0

 

0

 

0

 

 (a): 1 Aqua Resigen + 19 water. Dosage 40ml/ha. (0,003g. S-Bioallethrin + 0,216g. Permethrin/house)

 (b): 25 female mosquitoes/ cage and 25 larvae III - IV instar/ glass beaker for each distance. Test in 3 houses

 

Table 3: Densities of Aedes aegypti and Culex quinquefasciatus before and after Aqua Resigen ULV (a) indoor application in Nha Be townlet – HoChiMinh City, 1998.

Group

Pretreat-
ment

 

22/12/98

Post-treatment

After Ist time
23/12/98

After 2nd time
30/12/98

1 week
06/1/99

2 weeks
13/1/99

4 weeks
28/1/99

6 weeks
10/2/99

Den-sity

%
reduc.

Den-sity

%
reduc.

Den-sity

%
reduc.

Den-sity

%
reduc.

Den-sity

%
reduc.

Den-sity

%
reduc.

Trial group

– Aedes aegypti
(females/house)

– C. quinquefasciatus
(females/house)

 

1,9


2,5

 

0,4

0,7

 

78,9

72

 

0,2

0,3

 

89,5

88

 

0,5

1,4

 

73,7

44

 

0,7

2,7

 

63,2

0

 

1,5

4,9

 

21

0

 

1,7

3,3

 

10,5

0

Control group

– Aedes aegypti
(females/house)
– C. quinquefasciatus
(females/house)

 

2,1

4,5

 

2,4

5

 

–

–

 

2

2,4

 

–

–

 

2,8

3,7

 

–

–

 

3

5,7

 

–

–

 

3,6

4,1

 

–

–

 

2

3,4

 

–

–

 (a): 1 Aqua Resigen + 19 water. Dosage 40ml / house (0,003g S-Bioallethrin + 0,216g Permethrin/house).

 

 

Graph2: Percentage of death adult Ae. aefypti at different distances after 1 hour exposure to Aqua Resigen ULV in small-scale trial Combined data of 3 tests.


Graph 5: Density Aedes aegypti pre and post treatment Aqua Resigen ULV (n) indoor application, in Nha Be townlet- HoChiMinh City, 1998.