Does the subject and verb agree in this sentence Patch closure of the two defects was carried out?

Yes: the subject is "Patch closure", which is singular, and the verb "was" is also singular, so the subject and verb agree. "Two defects" is plural, but since it is not the subject, but rather the object of a prepositional phrase, it has no effect on the verb.

Speaking of subject/verb agreement, the question should begin "Do the subject and verb agree", because the subject is "subject and verb", which is plural, so you need to have a plural verb (do) rather than the singular (does).