>You mention that DDT programs were stopped prematurely because of bad data. However, how much did the FUD against DDT contribute to governments feeling pressur

>You mention that DDT programs were stopped prematurely because of bad data. However, how much did the FUD against DDT contribute to governments feeling pressure to stop DDT use, and then finding/not scrutinizing data that suggested they could stop? In Sri Lanka in particular, it was always scheduled to stop in 1963. The question is whether they might have re-started it earlier had it not been for the publication of Silent Spring the year before (n.b. Rachel Carson never called for DDT to be banned and only thought that indiscriminate use of any pesticide needed to be carefully considered). I'm not sure, maybe? But I doubt that this would affect Sri Lankan government policy towards a disease that had killed so many people. This: https://journals.plos.org/plosone/article/figure?id=10.1371/journal.pone.0043162.g001 https://journals.plos.org/plosone/article/figure?id=10.1371/... is a good timeline of the Sri Lankan programme. A few things are apparent: -The policy of indoor residual spraying (with DDT) works very well and knocks malaria way down. -Discontinuation of the spraying programme was after a few years of very low (reported) cases. -After the '67 outbreak, DDT IRS immediately restarted and was subsequently replaced by malathion IRS. DDT also discolours walls so there is a higher tolerance of alternatives, especially as case rates fall and people's memory of losing children to malaria starts to fade. Sri Lanka was only able to finally complete eradication after the end of the war with the LTTE and is sufficiently connected to India that the "eradication" has to be consider provisional. We can also look at the experience in South Africa. They stopped using DDT in 1996 and banned its use domestically, P. funestus re-emerged from neighbouring countries with a resistance to pyrethroids but not to DDT. This might seem like a case where the worry over DDT was harmful to human health even where it could usefully have been used but South Africa immediately unbanned it and deployed it in an indoor spraying campaign so I think it's actually an example of effective regulatory flexibility.