Pasadena got 0.2" of rain on Saturday. Temperatures were high with high humidity since than.The ants were back in the Control room east side benches.
We have started using TERRO Liquid Ant Baits in January 2015 This worked very well to this point.
Tree new packages were opened yesterday and the ants are gone.
We can conclude that these baits must be replaced after 6 mounts.
The liquid baits contains BORAX and it is safe.