Sept 22 (Reuters) - Costa Group Holdings said on Friday it has entered an agreement to be bought out by a consortium led by U.S. private-equity firm Paine Schwartz Partners in a deal valuing the horticulture company at A$1.50 billion ($962.6 million).

Shares of Costa surged as much as 7.9% by 0037 GMT, and topped the benchmark index, which was down 1.2%.

Under the proposal, Costa's shareholders would receive A$3.20 apiece for shares Paine Schwartz does not already own in the company, or a 10.3% premium to Costa's last closing price.

Costa expects the deal to complete in the first quarter of 2024, subject to shareholders' and regulatory approvals.

The consortium includes entities controlled by Paine Schwartz, Driscoll's and British Columbia Investment Management.

Paine had paid A$2.60 a share for a 13.78% stake in Costa in October. It increased its stake to 14.84% in late March, before starting discussions for a formal buyout bid in April.

The private-equity firm made an initial offer to buy Costa, Australia's leading grower, packer and marketer of fresh fruit and vegetables, at A$3.50 a share in July, but trimmed the offer earlier this week, deeming it the best and final price.

Costa, which in August reported a fall in its half-year profit and said it expects quality to deteriorate across its key citrus products, unanimously recommended that shareholders vote in favour of the deal.

($1 = 1.5584 Australian dollars) (Reporting by Himanshi Akhand in Bengaluru; Editing by Pooja Desai, Shounak Dasgupta and Sherry Jacob-Phillips)