The subject and verb in a sentence need to be in agreement. In case the noun phrase contains pre-modifiers or post modifiers (words/phrases that appear before/after the main word in a phrase, the verb needs to be in concord/agreement with the head word.
'The grapes in the basket is rotten' is incorrect.
'The grapes in the basket are rotten' is correct.
'Neither of the students are capable' is incorrect.
'Neither of the students is capable' is correct.
Moreover, in case of collective nouns, the noun is considered to be singular.