By law, the landlord owes a duty to the tenant to ensure the property is in good order. This is called a warranty of habitability. See See Jack Spring v. Little, 50 Ill.2d 351, 280 N.E. 2d 208 (1972); Glasoe v. Trinkle, 107 Ill.2d 1, 479 N.E.2d 915, 88 Ill Dec. 895 (1985).
What Can Tenant Do?
A tenant may file suit for breach of the warranty, OR, give the landlord reasonable notice to fix the problem in writing, and if the landlord does not do so in reasonable time, leave, and use it as a defense to eviction and to get the deposit back in small claims court.
The issue here will be who brought in the bugs? The landlord will claim the tenant did. The tenant will have to prove by preponderance of the evidence that they did not, and the property was/is infected due to landlord not taking care of it somehow.
I hope this helps and clarifies. Gentle Reminder: Use the SEND or REPLY button to keep chatting, or please rate when finished. You may always ask follow ups at no charge after rating. Kindly rate my answer as one of the top three faces/stars and then SUBMIT, as this is how I get credit for my time with you. Rating my answer the bottom two faces/stars or failing to submit the rating does not give me credit and reflects poorly on me, even if my answer is correct. I work very hard to formulate an informative and honest answer for you; please reciprocate my good faith.