Netting is cost effective for preventing bird damage
Melissa Hansen // Feb 15, 2005
A crew of five is needed to drape netting over single rows of Mark Barrett’s trees. Photo by Mike Bush/Good Fruit Grower)
Using netting for bird control is the surest way to prevent bird damage. In the past, application and removal was difficult for orchardists, but new applicators make netting cost-effective in some situations. Netting is catching on in Canada, according to Neal Carter, a grower in Summerland, British Columbia, who is also an agricultural consultant and bird-netting supplier. He estimates that 200 acres of cherries in British Columbia are under netting for bird protection.
Two stone fruit growers shared their netting experiences during the Cherry Institute annual meeting in Yakima, Washington. Mark Barrett has used netting for three years in cherries, peaches, and nectarines, resorting to netting when other methods failed to work in his late-season cherry orchards. He drapes netting over a single row of trees. John Verbrugge used netting wide enough to cover two rows of trees last year in a cherry block.
Barrett, who has orchards near Yakima, Washington, learned that having an isolated cherry orchard, several miles from another cherry block, attracted birds like a magnet. “My first commercial crop of Lapins cherries got completely eaten by birds. Robins were the initial problem, but lately, it’s been more from starlings.” Netting his young cherry trees in the first year was relatively easy, but as the trees get bigger, the task gets harder. “It’s a challenge putting the net over bigger trees.
When I started, the trees were three to four years old. Now, they’re seven-year-old trees.” He uses a netting platform/applicator developed for grapes to put the netting over his trees. As the trees grew taller, he modified the applicator, raising the arm from 12 to 18 feet. Applicator design need not be elaborate; some can be built by growers. The applicator can slip into a tractor’s bin forks and a fruit bin or pallet can be used to hold the netting. One company in British Columbia, Canada, offers netting applicator plans free of charge.
The netting process is relatively simple. One person on each side of the tree row holds the netting to keep it taut as the tractor drives down the row at a speed of about 1.5 miles per hour. He uses netting in widths that cover a 17-foot-wide swath, although netting comes as wide as 100 feet. Barrett is using netting with a life expectancy of three years, but expects another year or two from it. One bale of netting covers about one acre, depending on planting density.
He explained that workers use zip ties to gather the netting down under each tree canopy. To keep birds out, it’s important that the netting drapes to the ground and that there aren’t gaping holes. In windy sites, Barrett uses metal hoops or stakes at the end of rows to secure nets. “Birds do get trapped inside, but normally they don’t eat much,” he said. “We do try to get them out.” A bale of netting costs about $500, according to Barrett. Application costs are about $250 per acre. It takes a crew of five—two on the tractor and three on the ground.
Taking the netting off is much faster than putting it on. One crew can net four to five acres per day. Removal takes about 1.5 hours per acre and costs about $150 per acre. During removal, the netting is dropped loosely back into a bag. Barrett takes the net off right before picking, otherwise the birds move back en masse. Propane cannons are brought in when the nets are removed, even if it’s just for the evening before pickers come into the blocks. Special attention is paid to young trees when the netting is removed. “Young trees are more delicate,” Barrett said. His crew goes back into the orchard after netting removal to tip the young shoots and branches to ensure the tree is trained how they want.
With older trees, he’s found no effect on training and shoot position from the nets. During each of the past three years, he has netted about ten acres of his tree fruit. He cautions that when used in white nectarines and white peaches, the netting can cause scarring if fruit is “bunched near the netting.” Last year was the first time Barrett used netting as a stand-alone technique to control birds. “I didn’t see any difference from the years prior to last year. I do believe netting is a stand-alone tool as long as you close the gaps in the netting.”
With one year’s experience of netting a six-year-old Sweetheart cherry block, Verbrugge, co-owner and orchard manager for Valley Fruit of Wapato, Washington, is sold on the bird control tactic and plans to do more netting in coming years. Before netting, Verbrugge said he was losing about 10 percent of his total cherry crop annually to birds, with significant damage to early and late varieties.
In 2003, he lost 30 percent of his Sweetheart crop to birds; in 2004, 15 percent of his Tieton cherries were lost. Last year, he lost more than $4,000 from their total cherry acreage—30 acres of Sweetheart, Rainier, Bing, Lapins, and Tieton—from cullage in the field due to bird pecks. “Bird distress, pistols, cannons, screamers, guns—we tried everything. It just wasn’t working,” he said. Frustrated with detailing one person to bird control duties, Verbrugge set up a netting trial on a block of Sweetheart cherries in 2004.
The netting was only up for about two weeks because the block ripened faster than anticipated. He chose a high density, polyethylene yarn and used 58-foot-wide netting, enough to cover two rows of trees at a time. The netting was more expensive than some, but comes with a guarantee of ten years. Netting was applied with a Falcon applicator, an implement originally designed for vineyards that has been modified for orchards. The applicator arm reaches about 15 feet high, with the top bracket widened out to 12 feet.
A crew of three people put out the net, covering about one acre per hour. With the netting draped over two rows, workers can spray or pick without removing the netting. He calculated netting costs of around $1,700 per acre, with $40 per acre for labor to apply the netting. The applicator equipment cost $4,500. “If I just did one acre, it would cost a little more than $6,000,” he said. “But if you do more acres, it becomes cost-effective.” The cost drops to $1,975 per acre if used on 20 acres.
When considering netting as a bird control option, growers must calculate loss per acre in bird damage to determine if netting will pay for itself. Depending on crop tonnage and bird damage, losses of 10 percent from birds can range from $640 to more than $1,000 per acre at yields of four tons and seven tons per acre, respectively. He adds that if growers are picking good tonnage and the costs are spread over 20 acres, it will only take two to three years for the netting to pay off.
Next year, he will tie the net around the bottom of the trees, stabilizing the nets with zip ties for wind conditions. He believes netting is more effective than all other bird control options. “For most bird control tactics, we do a lot of running around but don’t get much done.”
Melissa Hansen is the research program director for the Washington Wine Commission. Hansen previously was an associate editor at Good Fruit Grower from 1996 through 2015. Read her stories: Author Index