In Business, Creating Sustainable Enterprises & Communities

PRODUCING PESTICIDE-FREE CHERRIES

In Business, May-June, Vol. 29, No. 3, p. 26

Marilyn Roberts builds on her adult education teaching role to develop a pest resistant netting.

Nancy Roulston and Larraine Roulston

IN THE HEART of British Columbia's Kootenay Mountains, Marilyn Roberts harvests deliciously ripe, worm free, cherries, without the use of pesticides. Kaslo resident Roberts - an adult education teacher in many subjects including chemistry and biology for Selkirk College - has two mature cherry trees on her property. After years of losing cherries to worms or having to pick them green before the pests invaded, she became frustrated and decided to concentrate on solving the problem.
Determined not to use harmful chemicals, Roberts tried soaps, oils, and even placed tarps on the ground to keep underground flies from surfacing. Eventually she began experimenting with fabrics. At first, nylon socks were tied around clumps of cherries. The following year, with limited success, she tied curtain material around branches which resulted in worm free fruit. Next, Roberts searched for a fabric netting that not only allowed moisture and sunlight to penetrate, but also was both durable and economical to cover a tree.
In 2005, after considerable research and testing, she purchased in excess of $500 worth of netting and created the first “Kootenay Cover” using her treadle sewing machine. This effort resulted in beautiful edible, poison-free cherries, and as a bonus, none were lost to birds. Roberts opened hundreds of cherries, removed the seeds and dried them for a great winter treat.
Roberts stated, “After an extensive search, I finally found a manufacturer who could make the perfect material and sew the cover bags for me (what a time-saver)! I bought nine to try out and sold them below cost to people with trees in return for a sample of their cherries for my data. The results were amazing! No worms in the trees which had been properly covered, although one bag came open on the ground and had a total of three wormy cherries in a sample of 50. Again, there was no loss to birds, and one person commented that he usually has a lot of wasps around the cherries, but this year there were no wasps in sight.”
As of February, Roberts now has these bags available to anyone who wants to protect their cherries. She is also striving to keep the cost under $100.00 for most sizes. The bags are made of a very durable material and have been treated to resist UV light damage. If the bags are removed with care after use, and stored clean in a cool dry place until the following year, they should last up to 10 years.
Even though Roberts is thrilled with the success of her pesticide-free bags, she is very enthusiastic about making them even more user-friendly. “After lots of experimentation, I discovered that by using Velcro and straps to hold one side up while the tree is being covered, the installation was quick and easy. These modifications were incorporated into the bags to make them even simpler.”
As Roberts has studied the life-cycle of cherry trees and also the organisms that invade it, she has focused solely on protecting this fruit. For optimum performance, Roberts places the bags over the trees around the first of June before the larvae life-cycle begins and removes them in mid-July when the cherries are ripe, spanning a period of six to seven weeks. If properly used, no worms should appear.
The weave of the material is too small for the flies to enter and lay their eggs, and yet do not trap humidity or moisture. Rather, in the presence of heavy rain, they allow water to penetrate like a mist. As this is a netting and not plastic, the trees breathe easily without being infected with pests. Rain that doesn't penetrate the netting rolls down to the drip line. Although Kaslo is not known for high winds, the trees are well protected from this kind of weather. None of Roberts' bags experienced any wind damage as it seems to pass through easily. However, in a nonsheltered area, if winds are severe, a potential problem could be that the netting turns the tree into a sail.
If a tree is pruned properly, there is minimal risk of tearing the bag during installation. On one poorly pruned tree, Roberts put plastic yogurt cartons over its sharp branches to protect the bag. The netting, being somewhat stretchy, conforms to the tree; however, if a rip does occur, it can be mended easily.
Two people can cover a small tree in less than 10 minutes. A larger tree takes four people twice as long. With the aid of several long poles, each topped with a tennis ball, each person can loop the bag's leading edge and lift it over the tree. When it is applied over the tree top, the straps are pulled and the last side drops. Some of her 16 foot bags were stretched over trees having a diameter in excess of 20 feet, which took a bit longer. With changes in the pattern to include the Velcro, the bags are applied relatively quickly. The cost of the improvement was slightly more than the original, but was well worth it.

HARVESTING WITHOUT SPRAYING
Cherry trees normally require frequent spraying to control flies. Cost-wise, Roberts calculates that although pesticides are cheaper, one still has to hire someone to spray. With proper care, Kootenay Covers (Registered Trade Mark) should last many years. For approximately $10/year, a tree will become laden with 100 percent organic produce. In addition, one can leave the tree covered for several more weeks to extend the picking season, allowing orchard owners more time to harvest without incurring extra spraying costs.
The trees thrive under the bags as they still absorb both sunlight and moisture while preventing a heavy rainfall from damaging this delicate fruit. As rain filters through, it should result in less splitting of cherries. The tree is healthier as well, for there is less leaf damage and the leaves are greener.
“Once I had a problem,” Roberts admitted. “I didn't check a tree for aphids before covering it; however, by putting ladybugs inside, the problem was resolved. Therefore it is best to check for aphids or other pests beforehand to avoid trapping them.”
“Although I don't sell my cherries, I strive to grow a healthy fruit for myself and at the same time be kind to the environment. The bags are designed for 12', 14' and 16' trees. I ordered 300 bags initially and hope to keep prices under or near $100 depending on the size. Currently I am offering workshops in the Kootenays and Okanagan Valley and have devised an information package for those on both sides of the border who are unable to attend.”
Roberts now has a patent pending on this product. For more information and workshop schedules, check out www.kootenaycovers.com. E-mail mroberts@kootenaycovers.com or call (250) 353-2264.

Nancy Roulston is a freelance writer/photographer and environmental science graduate, nancy_roulston@yahoo.ca. Larraine Roulston authors a series of children's adventure books on composting - www.castlecompost.com.