If the premises has been rendered uninhabitable by either ants or spray, then you may be able to withhold rent and find alternative accommodations. There are very specific steps you must take before employing this remedy and you should consult with an attorney before proceeding. Most importantly, you must notify the landlord in writing.
Mr. Bozarjian is an attorney licensed in California and Massachusetts. Please contact him directly through AVVO for help on your case. The information provided is not to be relied upon as final legal advice and does not create an attorney-client relationship.