Table 2. Major container types and numbers with pupae found during the wet season base line survey (November–December 2009) in Chennai.
Intervention | Control | |||||||||||
Type of container | Total number of container | Proportion to total containers | Container positive | Proportion to container+ve to total | No. of pupae in positive container | % of all pupae | Total number of containers | Proportion to total containers | Container positive | Proportion of container+ve to total | No. of pupae in positive container | % of all pupae |
Cement tank* | 73 | 0.021 | 19 | 0.062 | 366 | 7.34 | 58 | 0.019 | 22 | 0.099 | 431 | 13.14 |
Coconut shells | 14 | 0.004 | 5 | 0.016 | 89 | 1.79 | 6 | 0.002 | 5 | 0.023 | 52 | 1.58 |
Disused container | 156 | 0.045 | 87 | 0.282 | 1342 | 26.92 | 58 | 0.020 | 41 | 0.185 | 691 | 21.06 |
Flower vases | 25 | 0.007 | 16 | 0.052 | 329 | 6.59 | 16 | 0.005 | 7 | 0.031 | 130 | 3.96 |
Grinding stone | 55 | 0.016 | 31 | 0.101 | 514 | 10.31 | 41 | 0.014 | 32 | 0.144 | 692 | 21.09 |
Plastic/metal drum | 260 | 0.076 | 63 | 0.205 | 1222 | 24.51 | 193 | 0.066 | 36 | 0.162 | 558 | 17.00 |
Plastic pot | 1434 | 0.417 | 17 | 0.055 | 205 | 4.11 | 1168 | 0.397 | 13 | 0.595 | 53 | 1.62 |
Tyres | 24 | 0.007 | 21 | 0.068 | 279 | 5.60 | 14 | 0.005 | 13 | 0.595 | 166 | 5.06 |
Miscellaneous† | 1396 | 0.406 | 49 | 0.159 | 639 | 12.82 | 1387 | 0.472 | 53 | 0.239 | 508 | 15.48 |
Total (including all containers | 3437 | 308 | 4985 | 2941 | 222 | 3281 |
Notes: *Cement tanks, which were the predominant producers of Aedes pupae, had lost their relative importance after the Corporation (public sector) had treated them with temephos, just before our survey in the wet season.
†Miscellaneous containers recorded were ceramic jar, bowl, bucket, metal containers, mud pot, refrigerator trays, and tree holes.