Ernie from Tempe, Az writes
I sprayed a strong concentration of Bifen IT mixture directly on a spider and it had no effect. Is there something I can mix with the Bifen to get spiders?
Bifen IT is not designed to kill on contact and even when you spray an insect directly it can take several minutes or longer to kill it. It will help to kill the ones that contact a treated surface as well as their food source, but how long it takes to kill after application depends on age and health of the insect, how long after application they contact the treated surface and how long they spend on the treated surface. Spiders themselves are harder to kill as they do not groom themselves and have the long legs to keep themselves off the ground and in more contact with a treated surface. We have a great guide here for treating spiders that might also help. If you are going to be spraying spiders directly each time, you could add a product like ExciteR to Bifen to give it a faster initial knockdown only.
Answer last updated on: 10/17/2016
