Royal Hawaiian Orchards LP suffered a $3.7 million loss last year as dry weather, insect damage and efforts to expand sales of its fledgling brand of packaged snack foods took a toll on Hawaii’s biggest macadamia nut grower.

The loss reported Friday in an earnings annoucement and annual report was the biggest in seven years for the Hilo-based company and compared with a $499,000 loss in 2012.

Much of last year’s loss was due to a poor harvest that ranked as the second-lowest in 20 years for the company formerly known as ML Macadamia Orchards.

The company said inadequate rainfall in its Kau orchard during a period when nuts were in a key development stage was a major factor in the decline. Another factor was an insect native to Australia called the Macadamia Felted Coccid that damaged 500,000 pounds of nuts last year.

Nut sales for Royal Hawaiian plunged 45 percent to $9.9 million last year from $18 million the year before. The drop was primarily due to a 5.8 million pound decline due to the poor harvest and 6.1 million pounds reserved for a new line of snack products.

Royal Hawaiian increased snack sales to $2.1 million last year from $91,000 the year before, but also incurred $1.9 million in costs for those sales last year.