MOSQUITO CONTROL

Abstract

A method of controlling mosquito populations is disclosed. The method includes: placing a plurality of ovitraps into an area where it is desired to reduce a mosquito population; filling the ovitraps with water; introducing a defined larvicidal amount of a water conditioning agent comprising cow urine into a given volume of water into the ovitraps to condition the water absent of a separate or additional pesticide; leaving the conditioned water for at least 7 weeks; and monitoring at least one of the ovitrap and the area to determine effectiveness.

Claims

1. A method of controlling mosquito populations comprising: Placing a plurality of ovitraps into an area where it is desired to reduce a mosquito population; Filling the ovitraps with water; Introducing a defined larvicidal amount of a water conditioning agent comprising cow urine into a given volume of water into the ovitraps to condition the water absent of a separate or additional pesticide; Leaving the conditioned water for at least 7 weeks; and Monitoring at least one of the ovitrap and the area to determine effectiveness.

2. A method as claimed in claim 1, wherein the cow urine is derived from Bos indicus or Zebu cattle.

3. A method as claimed in claim 1, wherein the mosquito population targeted is from the subfamily Anophelinae.

4. A method as claimed in claim 1, wherein the mosquito population targeted is from the subfamily Culicinae.

5. A method as claimed in claim 3, wherein the mosquito population targeted is from the genus Anopheles and is configured to control human malaria.

6. A method as claimed in claim 4, wherein the mosquito population targeted is from the genus Culicine and is configured to control yellow fever or Dengue fever.

7. A method as claimed in claim 1, wherein the monitoring further comprises at least one of monitoring adult mosquito numbers, monitoring a number of eggs deposited, and determining a number of dead larvae.

8. A method as claimed in claim 1, further comprising deploying a plurality ovitraps per acre.

9-17. (canceled)

18. A method as claimed in claim 2, wherein the monitoring further comprises monitoring adult mosquito numbers.

19. A method as claimed in claim 2, wherein the monitoring further comprises monitoring a number of eggs deposited.

20. A method as claimed in claim 2, wherein the monitoring further comprises determining a number of dead larvae.

21. A method as claimed in claim 2, wherein the monitoring further comprises monitoring adult mosquito numbers, monitoring a number of eggs deposited, and determining a number of dead larvae.

22. A method as claimed in claim 3, wherein the cow urine is derived from Bos indicus.

23. A method as claimed in claim 3, wherein the cow urine is derived from Zebu cattle.

24. A method as claimed in claim 4, wherein the cow urine is derived from Bos indicus.

25. A method as claimed in claim 4, wherein the cow urine is derived from Zebu cattle.

26. A method of controlling mosquito populations comprising: Placing a plurality of ovitraps into an area where it is desired to reduce a mosquito population; Filling the ovitraps with water; Conditioning the water by introducing a defined larvicidal amount of a water conditioning agent comprising cow urine into a given volume of water into the ovitraps, wherein the water is absent of a separate or additional pesticide; Leaving the conditioned water for at least 7 weeks; and Monitoring the ovitrap to determine effectiveness after leaving the conditioned water for at least 7 weeks.

27. A method as claimed in claim 26, wherein the cow urine is derived from Bos indicus.

28. A method as claimed in claim 26, wherein the cow urine is derived from Zebu cattle.

29. A method as claimed in claim 26, wherein the monitoring further comprises at least one of monitoring adult mosquito numbers, monitoring a number of eggs deposited, and determining a number of dead larvae.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Embodiments of the invention are further described hereinafter with reference to the accompanying drawings, in which:

[0065] FIG. 1 is a, non-limiting, flow diagram indicative of the larvicidal process,

[0066] FIG. 2 is a graph showing eggs laid at a first location;

[0067] FIG. 3 is a graph showing OPI (Ovitrap Positivity Index) and EDI (Egg Density Index) at a first location;

[0068] FIG. 4 is a graph showing eggs laid at a second location; and

[0069] FIG. 5 is a graph showing OPI and EDI at a second location.

DETAILED DESCRIPTION

[0070] The cow urine was tested in two field experiments as set out below:

Field Testing of Ovitraps:

[0071] Field trials were conducted using 2 concentrations of a liquid and solid (re-dissolved) cow urine, as per the treatment details below:

Treatment Details:

[0072] T1: Bioactive 1—CU (Cow Urine)—10%, 15% (vol/vol)

[0073] T2: Bioactive 2—Tablet (Cow Urine concentrate tablet)—10%, 15% (weight/vol)

[0074] Control: Water

Test Locations:

[0075] Two different test locations were used.

[0076] Location 1 was a 40-acre area including a school, hostel, health centre, human dwellings, cattle sheds and open water tanks with likely mosquito breeding. Twenty-six ovitraps with different treatment concentrations and control water were randomly placed across the location, spread across >3000 m.sup.2 area.

[0077] Location 2 was a 30-acre area, characterised by villas, restaurants and hotel accommodation interspersed with wild vegetation that comprise shrubs, trees and large open grass lands. Twenty ovitraps with different treatment concentrations and control water were randomly placed across Location 2, spread across >2000 m.sup.2 area.

[0078] In both of the test locations the traps were randomly distributed by generating random numbers in the respective area, complying to randomised complete block design (RCBD statistical design).

Observations:

[0079] Paper strips placed in ovitraps for egg detection were changed once every week. The strips were brought to the laboratory and the number of eggs were counted per strip under a stereo-binocular microscope.

[0080] Immature larvae of >2 instar, if any found in traps, were brought in a vial and used for identification, up to species level.

Results:

Location 1:

[0081] The results are illustrated in FIG. 2.

[0082] They show there was egg laying in all treatments and all traps right from the 1.sup.st week of the study.

[0083] In both treatments (T1 and T2), the total number of eggs and mean number of eggs was 2-3-fold higher compared to control. Both the total and mean number of eggs per trap increased with time in treatments and was lowest in the control. Total and mean numbers of eggs in control traps was lowest at 11 weeks. Always, mean number of eggs laid in control traps ranged between 200-450. Mean number of eggs was as high and >600 in T2 at a concentration of both 10% and 15%. The number of eggs laid in T2 was highest even on 11.sup.th week of the field test (>600). Both the treatments were more attractive to the gravid female mosquitoes compared to control traps all through the study. Total and mean number of eggs laid per trap traced an increasing trend in treatments especially in T2 on 11.sup.th week as well, at both the concentrations. Aedes aegypti and Aedes albopictus mosquitoes were reported from first week in all the traps. Armigera sp. were attracted for oviposition from 3.sup.rd week onwards. From 7.sup.th week onwards, Culex quinquefasciatus also was attracted for oviposition.

[0084] On the 11.sup.th week, the contents in all traps were replaced with fresh solutions, for all treatments including controls. By 11.sup.th week, gravid females of Aedes albopictus and Armigera sp. were dominant in the traps, including control. Population of Aedes aegypti reported in the test traps by way of egg laying was reduced drastically by 11.sup.th week. The number of adults representing the population also showed reduced number of Aedes aegypti and Culex sp. compared to Aedes albopictus and Armigera sp. The population of adults drastically reduced up to 5-acre area, as evident by adult sampling during evening hours using sweep net.

[0085] Referring to FIG. 3 all the traps including control did recorded egg laying by mosquitoes from 1.sup.st week. OPI (Ovitrap Positivity Index) was 100 for treatments and above 50 for control traps throughout the study period. EDI (Egg Density Index) increased with time, showing considerable fluctuations. EDI did depict a linear stepping up (trend line) indicating a positive correlation in egg density in ovitraps with time. From the 2.sup.nd week, the EDI was high in all treatments compared to control and a general trend followed. As per the data on 11.sup.th week, highest EDI was obtained for T1 (200) followed by T2 (>150). The EDI for control traps was always low and fluctuated between 25-80 throughout the study until 9.sup.th week. By 11.sup.th week, despite OPI being >50 for all treatments and control, EDI reduced drastically. On 11.sup.th week, T2, C2 recorded highest EDI of ˜120, followed by T2, C1 and lowest was in control traps. Clearly there exists a significant positive correlation between EDI and time.

Location 2:

[0086] Referring to FIG. 4, egg laying, mostly by Aedes aegypti and Aedes albopictus, was noticed in control as well as treatments (T1, T2) at all concentrations. In both treatments, total number of eggs and mean number of eggs was 2-3-fold higher compared to control. Number of eggs (mean and total) increased with time in both treatments till 10.sup.th week and ranged from 600-1400 and was lowest in control (<200). Total and mean number of eggs in control traps was lowest at all 10 weeks of observation. Always, mean number of eggs laid in control traps ranged between 30-300. Aedes aegypti and Aedes albopictus mosquitoes reported from first week in all the traps. Armigera sp. were attracted for oviposition from 3.sup.rd week onwards. From 7.sup.th week onwards, Culex quinquefasciatus also was attracted for oviposition. At 11.sup.th week of the study, T1 and T2 showed increasing attractiveness to the gravid females as shown by the number of eggs. At 11.sup.th week, the mean no. of eggs was >1400 in T1 and ˜500 in T2. Mean number in control traps was 100 on the 11.sup.th week of the study. Both the treatments were more attractive to the gravid female mosquitoes compared to control traps all through the study. The population of adults drastically reduced up to 5-acre area as evident by adult sampling during evening hours using sweep net. The mosquito population in the area around the trap has been reduced which is attributable to the presence of traps. The presence of conditioned water in traps (T1, T2) have been highly attractive to the fecund gravid females of different genera and species. The presence of dogs is also favouring them, providing them constant hosts for blood feeding. Despite this, in an area of about 5 acres which is covered by grasses and trees, mosquito activity was not observed, even during peak hours of the evening (4.00 pm to 7.30 pm), which is undoubtedly because of the population reduction by way of deploying the ovitraps with water conditioners.

[0087] Referring to FIG. 5, OPI (Ovitrap Positivity Index) was 100 for treatments and above 50 for control traps throughout the study period. EDI (Egg Density Index) increased with time and did show a linear stepping up (trend line) indicating a positive correlation in egg density in ovitraps with time. From 2.sup.nd week, the EDI was high in all treatments compared to control and the trend followed. At 11.sup.th week, the EDI was highest in T1 (>300), followed by T2 (>125) and was lowest in the control (25). There exists a significant positive correlation between EDI and time. Aedes aegypti and Aedes albopictus mosquitoes reported from first week in all the traps. Armigera sp. were attracted for oviposition from 3.sup.rd week onwards. From 7.sup.th week onwards, Culex quinquefasciatus also was attracted for oviposition. On 11.sup.th week, Armigera and Aedes albopictus were more frequently reported in the traps and incidence of Aedes aegypti was very occasional. The adult samples collected in the 5-acre area also revealed a similar pattern.

Sequence of Mosquito Genera and Species Reporting in Universal Ovitraps:

[0088] The field trials demonstrated the use of cow urine was effective in attracting and killing a range of different species.

[0089] The range is illustrated in Table 3 below which shows weekly occurrence of different genera and species of mosquitoes reported to lay eggs in Ovitraps in test location

TABLE-US-00003 TABLE 3 Mosquito genera, species Sl. No. Date Week Treatment (L1) (L2) 1 24 Sep. 2018 Week 1 T1C1 Aedes sp. Aedes sp. 2 T1C2 Aedes sp. Aedes sp. 3 T2C1 Aedes sp. Aedes sp. 4 T2C2 Aedes sp. Aedes sp. 5 Control Aedes sp. Aedes sp. (Water) 6 1 Oct. 2018 Week 2 T1C1 Aedes sp. Aedes sp. Aedes albopictus Aedes aegypti Aedes albopictus 7 T1C2 Aedes sp. Aedes sp. 8 T2C1 Aedes sp. Aedes sp. Aedes albopictus Aedes albopictus 9 T2C2 Aedes sp. Aedes sp. Aedes albopictus 10 Control Aedes sp. Aedes sp. (Water) Aedes albopictus Aedes albopictus 11 8 Oct. 2018 Week 3 T1C1 Aedes sp. Aedes aegypti Aedes albopictus Aedes albopictus 12 T1C2 Aedes sp. Aedes sp. Aedes albopictus Armigera sp. 13 T2C1 Aedes sp. Aedes sp. Aedes albopictus Aedes albopictus 14 T2C2 Aedes sp. Aedes aegypti Aedes albopictus Aedes albopictus 15 Control Aedes sp. Aedes sp. (Water) Aedes albopictus Aedes albopictus 16 15 Oct. 2018 Week 4 T1C1 Aedes sp. Armigera sp. Armigera sp. Aedes albopictus 17 T1C2 Aedes sp. Armigera sp. Armigera sp. Aedes aegypti Aedes aegypti Aedes albopictus Aedes albopictus 18 T2C1 Aedes sp. Armigera sp. Aedes albopictus Aedes albopictus 19 T2C2 Aedes sp. Aedes sp. Armigera sp. Armigera sp. Aedes albopictus Aedes albopictus 20 Control Aedes sp. Aedes sp. (Water) Aedes albopictus Aedes aegypti Aedes albopictus 21 22 Oct. 2018 Week 5 T1C1 Aedes sp. Armigera sp. Armigera sp. Aedes albopictus Aedes albopictus Aedes sp. 22 T1C2 Armigera sp. Armigera sp. Aedes aegypti Aedes albopictus Aedes albopictus Aedes sp. 23 T2C1 Armigera sp. Armigera sp. Aedes aegypti Aedes albopictus Aedes albopictus Aedes sp. 24 T2C2 Aedes sp. Aedes aegypti Aedes albopictus Aedes albopictus Aedes sp. 25 Control Aedes sp. Aedes aegypti (Water) Aedes albopictus Aedes albopictus Aedes sp. 26 29 Oct. 2018 Week 6 T1C1 Aedes albopictus Aedes albopictus Armigera sp. Armigera sp. Aedes sp. Aedes sp. 27 T1C2 Aedes albopictus Aedes albopictus Armigera sp. Armigera sp. Aedes aegypti. Aedes sp. 28 T2C1 Aedes albopictus Aedes albopictus Armigera sp. Armigera sp. Aedes aegypti Aedes sp. 29 T2C2 Aedes albopictus Aedes albopictus Aedes sp. Aedes aegypti Aedes sp. 30 Control Aedes albopictus Aedes albopictus (Water) Aedes sp. 31 5 Nov. 2018 Week 7 T1C1 Aedes albopictus Armigera sp. Aedes aegypti Aedes sp. Aedes sp. 32 T1C2 Aedes sp. Armigera sp. Aedes sp. 33 T2C1 Aedes albopictus Aedes albopictus Aedes sp. Aedes sp. Culex quinquefasciatus 34 T2C2 Aedes albopictus Armigera sp. Aedes sp. Aedes sp. 35 Control Aedes albopictus Armigera sp. (Water) Aedes aegypti Aedes sp. Aedes sp. 36 12 Nov. 2018 Week 8 T1C1 Aedes albopictus Armigera sp. Aedes aegypti Aedes sp. Aedes sp. 37 T1C2 Aedes sp. Armigera sp. Aedes sp. 38 T2C1 Aedes albopictus Aedes albopictus Aedes sp. Aedes sp. Culex quinquefasciatus 39 T2C2 Aedes albopictus Armigera sp. Aedes sp. Aedes sp. 40 Control Aedes albopictus Armigera sp. (Water) Aedes aegypti Aedes sp. Aedes sp. 41 19 Nov. 2018 Week 9 T1C1 Armigera sp. Armigera sp. Aedes sp. Aedes sp. 42 T1C2 Aedes sp. Aedes sp. 43 T2C1 Aedes albopictus Aedes albopictus Aedes sp. Aedes sp. Armigera sp. 44 T2C2 Aedes albopictus Aedes albopictus Aedes sp. Aedes sp. 45 Control Aedes albopictus Aedes albopictus (Water) Aedes sp. Aedes sp. 46 26 Nov. 2018 Week 10 T1C1 Armigera sp. Armigera sp. Aedes albopictus Aedes sp. 47 T1C2 Aedes sp. Aedes albopictus Armigera sp. Aedes sp. Armigera sp. 48 T2C1 Aedes albopictus Aedes sp. Aedes sp. Armigera sp. 49 T2C2 Aedes albopictus Aedes aegypti Aedes sp. Aedes sp. Armigera sp. 50 Control Aedes albopictus Aedes albopictus (Water) 51 3 Dec. 2018 Week 11 T1C1 Armigera sp. Armigera sp. Aedes albopictus Aedes sp. Aedes sp. 52 T1C2 Aedes sp. Aedes albopictus Armigera sp. Aedes sp. Armigera sp. 53 T2C1 Aedes albopictus Aedes sp. Aedes sp. Armigera sp. 54 T2C2 Aedes albopictus Aedes aegypti Aedes sp. Aedes sp. Armigera sp. 55 Control Aedes albopictus Aedes albopictus (Water) Aedes sp. 56 10 Dec. 2018 Week 12 T1C1 Armigera sp. Aedes albopictus Aedes sp. Aedes sp. Armigera sp. 57 T1C2 Aedes sp. Aedes albopictus Aedes sp. Armigera sp. 58 T2C1 Aedes albopictus Aedes albopictus Aedes sp. Aedes sp. 59 T2C2 Aedes sp. Aedes albopictus Aedes sp. Armigera sp. 60 Control Aedes albopictus Aedes albopictus (Water) Aedes sp. Aedes sp. 61 17 Dec. 2018 Week 13 T1C1 Aedes sp. Aedes sp. Armigera sp. 62 T1C2 Aedes sp. Aedes sp. 63 T2C1 Aedes albopictus Aedes sp. Aedes sp. Armigera sp. 64 T2C2 Aedes sp. Aedes sp. 65 Control Aedes albopictus Aedes sp. (Water) Aedes sp. 66 24 Dec. 2018 Week 14 T1C1 Aedes sp. Aedes sp. 67 T1C2 Aedes sp. Aedes sp. Armigera sp. 68 T2C1 Aedes sp. Aedes sp. Armigera sp. 69 T2C2 Aedes sp. Aedes sp. Armigera sp. 70 Control Aedes sp. Aedes sp. (Water) Armigera sp. Aedes albopictus 71 31 Dec. 2018 Week 15 T1C1 Aedes sp. Aedes sp. Armigera sp. 72 T1C2 Aedes sp. Aedes sp. Armigera sp. 73 T2C1 Aedes sp. Aedes sp. Armigera sp. Armigera sp. 74 T2C2 Aedes sp. Aedes sp. Armigera sp. Armigera sp. 75 Control Aedes sp. Aedes albopictus (Water) Armigera sp. Aedes sp. 76 7 Jan. 2018 Week 16 T1C1 — Aedes sp. Armigera sp. 77 T1C2 Aedes sp. Aedes sp. Armigera sp. 78 T2C1 Aedes sp. Aedes sp. Armigera sp. Aedes albopictus 79 T2C2 Aedes albopictus Aedes sp. Aedes sp. Armigera sp. 80 Control Aedes albopictus Aedes albopictus (Water) Aedes sp. 81 14 Jan. 2018 Week 17 T1C1 — Aedes sp 82 T1C2 — Aedes sp 83 T2C1 — Aedes albopictus 84 T2C2 Aedes sp. — 85 Control Aedes albopictus — (Water) 86 21 Jan. 2018 Week 18 T1C1 Aedes sp Aedes albopictus 87 T1C2 — — 88 T2C1 Aedes albopictus — 89 T2C2 Aedes sp — 90 Control Aedes albopictus — (Water) 91 29 Jan. 2018 Week 19 T1C1 — Aedes sp 92 T1C2 — — 93 T2C1 Anopheles sp. Aedes sp 94 T2C2 — — 95 Control Aedes albopictus Aedes sp (Water)

[0090] Interestingly, the field trials conducted at both field sites, revealed a sequence in the genera and species of mosquitoes reported in the ovitraps from 1.sup.st to 8.sup.th week. The pattern indeed is very consistent across locations and suggests that the traps become increasingly attractive to egg laying gravid females of diverse groups of mosquitoes and continues to get significant number of eggs deposited on 8.sup.th week post water conditioning.

[0091] The first species of mosquito to get attracted to the traps in both the study sites was from 1.sup.st week was Aedes albopictus and Aedes aegypti. They continued to report till 9.sup.th week. From the 3.sup.rd week onwards, the traps also attracted a new genus of mosquitoes i.e., Armigera sp. Other significant facts emerging from our study was the traps did attract Culex quinquefasciatus mosquitoes from 7.sup.th week of the initiation of the field test and this was true for both the locations. Culex quinquefasciatus is a vector of lymphatic filariasis and arboviruses including St. Louis encephalitis virus and West Nile virus. Also, Anophonles sp were detected.

CONCLUSIONS

[0092] The CU and Tablets were both highly effective in attracting gravid females of mosquitoes for egg laying. The attractiveness was evident by higher oviposition rates in them compared to control traps during the study period. The traps attracted gravid females of Aedes aegypti, Aedes albopictus, Armigera sp., Culex quinquefasciatus and Anophonles sp as evident by identification of larvae collected from the traps. The feedback from people living in both study locations also implies reduced mosquito activity in open areas. The significant feature is that both the treatments were preferred over control for oviposition, even at 10.sup.th week of the study. The effect of treatments that differentiated them form water cannot be ignored and this effect persisted even by 10.sup.th week of the trial. In both locations, in an area of about 5 acres which is covered by grasses, and trees, Applicant did not find mosquito activity even during peak hours of the evening (4.00 pm to 7.30 pm), which was undoubtedly due to population reduction by way of deploying the ovitraps with water conditioners. The attractiveness of conditioned water remained effective in L2 while in L1, it reduced. The fact that the population density indices (EDI, Adult abundance) was always low in L1 compared to L2 cannot be ignored. The study clearly indicates that the cow urine and the cow urine tablets used here for water conditioning remain attractive/effective for >10 weeks, which is of great significance.

[0093] On the basis of the finding it is proposed that the methodology could replenish the ovitraps with conditioned water every 8 to 12 weeks, e.g. bimonthly or quarterly.

[0094] In summary, the experiments indicate that cow urine deployed in multiple ovitraps per acre reduced the population effectively in <10 weeks by attracting the adults to deposit their eggs in high densities and interfering with lifecycle of the vector, in effect bringing about larval and adult reduction.