Sept 18 (Reuters) - Costa Group Holdings Ltd said on Monday U.S. private equity firm Paine Schwartz Partners (PSP) reduced its non-binding takeover offer for shares it doesn't already own, valuing the horticulture company at A$1.49 billion ($958.4 million).

Under the proposal, Costa's shareholders would receive A$3.20 apiece for the remaining 85.16% stake PSP does not already own, lower than the A$3.50 apiece offer received in July.

PSP has also indicated that this offer is the best and final price at which the PSP-led consortium can deliver the proposed transaction, Costa said in a statement.

Costa, Australia's leading grower, packer and marketer of fresh fruit and vegetables, added that it is considering the lower offer and is continuing to engage with PSP regarding the terms and conditions.

PSP did not immediately respond to a Reuters request for comment. ($1 = 1.5547 Australian dollars) (Reporting by Himanshi Akhand in Bengaluru; Editing by Lisa Shumaker)