Question

I saw one of your lectures on faith / belief in which you criticized the state of humanity for eating animals (meat and the like).
There is no shortage of medical studies showing that not eating meat / poultry / fish / eggs can cause medical problems, and apparently for many people becoming vegan would cause health issues (though it is important to note that there are also plenty of people who testify about themselves as vegans that they live healthily). 
If I sum up the medical situation regarding eating meat: apparently it is not absolutely necessary to eat it, but it is recommended.
Is killing insects, for example spraying cockroaches while causing the cockroach terrible suffering (seeing a cockroach dying is really not simple, and apparently it hurts for a much longer time than animals that are slaughtered and suffer for no more than a few seconds), not morally problematic?
The assumption is that, as with the issue of meat, apparently if we do not spray there could be health problems. On the other hand, as with giving up meat, there will not necessarily be health problems, and even if there is an issue of sterilization or certain health problems that might arise because of cockroaches in the house (for example), it is possible to live with that too, just as it is possible to live with lower iron levels in the body because of veganism. 
And another assumption: we are not killing insects because they are “a nuisance in the home or yard environment.” If being a nuisance permits killing and causing suffering to an insect, then one could also say that killing cats that hang around the garbage bins is legitimate too (I assume you would agree that it is not). 
 
So morally speaking, to spray or not to spray?