Fig. 3

Vector control releases can achieve disease fade-out for sparse drug coverage when biting rates are below \(b<1.2\). The critical release ratio \(u=u_{\mathrm {c}}\) that leads to disease fadeout (\(h^*\rightarrow 0\)) for a given treatment proportion w as the mosquito biting rate b varies, as calculated using (46) and (47). The release ratio u is of the current vector population A(t) rather than the equilibrium population \(A^*\) (elsewhere in the paper the ratio of \(A^*\) is used). Early and late SIT are compared; all other parameters as in Table 1