BASF, the world's largest chemicals maker, is to buy U.S. crop protection company Becker Underwood from buyout firm Norwest Equity Partners for $1.02 billion to boost its farming pesticides division, the German group said on Thursday.

BASF's largest deal since its 2010 acquisition of Cognis, which makes additives for household products, continues its strategy of buying into industries that are less dependent on the business cycle than its core chemicals and plastics businesses catering to industrial customers.

Becker Underwood, which expects sales of $240 million in 2012, is a global provider of seed treatments, biological crop protection products, gardening products and animal nutrition.

Seeds treatments are chemical coatings that protect seeds and germ buds against microbes and fungi.

The purchase helps BASF keep up with larger pesticides rivals Syngenta, Bayer and Dupont's Pioneer unit.

BASF's Chief Executive Kurt Bock said in July that ample liquidity and cash reserves were available for deals.

Also that month, BASF's Agricultural Solutions division posted record quarterly operating earnings as farmers used more pesticides to get the most out of a surge in grain prices, while BASF industrial units faced weaker markets.

BASF said on Thursday that the pesticides division "is expecting another top year in 2012" after record sales of €4.2 billion ($5.48 billion) last year.

The Becker Underwood deal is subject to regulatory approval and the transaction is expected to be completed by the end of this year, BASF added.