There’s nothing more frustrating than packing beautiful potatoes, only to have them hit with a penalty or rejected for bruising when they reach their processing destination. Most farmers understand the problem — potatoes get nicked and beat up during harvest, cleaning and load-in, but generally heal during storage. As the potatoes run across a producer’s packing line, the potatoes look good. Unfortunately, they’re hiding nasty secrets — hidden pressure bruise, black spot and shoulder bruise which often doesn’t colour-up until the potatoes pack, ship, then hit water at the processor. Add bruising which occurs during load-out, and the costs to producer can be brutal. Luckily, there is another option.
1,4-DMN (1,4-dimethylnaphthalene) is a naturally occurring hormone that potatoes release to initiate and maintain tuber dormancy. In the mid-1980s, scientists isolated 1,4-DMN, then tested and proved it to be a safe, effective and fully-reversible dormancy-enhancer when fogged onto a potato pile. In the years since, 1,4-DMN has been commercially formulated for sale as 1,4SIGHT (for use in chippers, processing potatoes and tablestock) and 1,4SEED (for use in seed potatoes or mixed table/seed piles).
1,4-DMN does more than just manage sprouting. When applied at door close-up, 1,4-DMN triggers genes which control water loss and decrease respiration, increasing potatoes’ turgidity, decreasing shrinkage, and reducing pressure bruise in the early storage season.
When applied close to bin load-out (two to six weeks from shipping), 1,4-DMN triggers genes in tubers which make bruising much less visible. Specifically, 1,4-DMN reduces the biosynthesis of phenylalanine, a key component in bruising, masking discoloration.
How well does the late-season application protect from hidden bruising? Impressively well, says Ragen Darrington, a regional sales rep with 1,4Group distributor IVI Inc.
“You can see it in growers’ bottom line. They’re getting more dollars when they use 1,4SIGHT. They’ve shown me four or five years of their farm data, and their load rejections drop immediately when they start using 1,4SIGHT. It’s the only thing they’ve added to their storage protocol, and it’s a direct and obvious benefit.”
About five years ago, Darrington was part of some on-farm trials testing 1,4SIGHT.
“We compared potatoes that weren’t treated with 1,4-SIGHT to ones that got hit with a fairly high rate of DMN about a week before we took them out of storage. In all other ways, they were the exact same potatoes, grown in the same field, out of the same storage, stored the same way. The results were very consistent — the treated potatoes had close to 30 per cent better bruise-free compared to the untreated,” he says.
Recommending 1,4-DMN is easy, he says, since “pretty much everyone” can see good return on investment from 1,4SIGHT’s bruise-reducing feature.