- Written by Christine Rowe
- Business reporter technology
It’s a simple, elegant solution to an age-old problem: to protect crops from dangers, and to keep them covered.
Netting is commonly used to keep pests out in vegetable production, particularly in high-value areas such as seeds.
However, in fruit production, the use of nets is still being explored and tested, according to Mirella Aoun, an agricultural engineer and researcher at Bishop University in Quebec, Canada, who has been studying agricultural nets for more than a decade.
Professor Aoun explains that fruit producers initially placed nets on the trees to protect them from hail damage. Now they are experimenting with nets that can protect against insects.
The size of the insect-proof netting is determined by the local conditions, including the nature of the insects.
Of course that could kill off the insects farmers really want – pollinators like bees.
One option is to apply curling iron after the pollination period. Another thing is to open the nets during the day, and bring in the hives.
Tree netting is particularly well established in French and Italian apple orchards, where Nets draped over rows of apple trees Reducing the movements and laying of eggs of the codling moth. This has helped farmers get rid of perennial pests and reduce their use of costly and environmentally damaging chemical pesticides.
There are benefits for fruit lovers, too. “When you know you have less pesticide residue than crops that are subject to exclusion nets, that’s great news for consumers,” says Professor Aoun.
Networks are also seen as a way to address the effects of climate change. Warmer conditions have seen the resurgence of some types of insects and diseases.
Some areas experience more intense periods of drought and heavy rains and nets can help with this.
For example, depending on the location, the type of netting, and the way it is used, a netting system can protect against solar radiation that leads to heat stress and inhibit photosynthesis in trees.
But inserting a netting could mean a wetter environment around the tree—not helpful for crops susceptible to fungal diseases in humid climates such as the northeastern United States and Canada.
But some researchers Work on waterproof netswhere treatment with phytoncides renders the nets essentially water-repellent.
Photo-selective (colorful) lattices can also affect light penetration. Dark and opaque grilles reduce the intensity of the light but not the quality of the light.
The pearly netting can better scatter the light so that it reaches more parts of the vegetation. Meanwhile, the blue, red and yellow grids filter out specific solar wavelengths and can thus induce specific responses in plants related to fruit quality.
Fine-tuning the use of the net often results in higher-quality fruit, according to Professor Aoun. like searched in the Mediterranean It has shown that trees covered with colorful shade nets can produce larger, brightly colored fruits.
Networking is not always the answer. May not be suitable for smaller, more diverse orchards. Nor is it necessary for all weather conditions.
Also, the netting used to grow fruit trees is usually made of polyethylene, which isn’t ideal for a world trying to wean off plastic dependence.
One company in the business of non-plastic netting is Texinov, a French technical textile company. Texenov is researching different types of net that are biodegradable, such as those made from flax.
It has already introduced a biodegradable mesh made of polylactic acid (PLA), which is produced from fermented corn. Synthetic fertilizer is needed to break down this type of net, which sales manager Adrien Etienne says is about 10% more expensive than traditional net.
Biodegradable nets are now more popular in Europe than in North America, Etienne says. This may be related to European policies aim to reduce Use of pesticides. “I think mosquito nets will become more popular because pesticides are less common,” says Etienne, for example, among French cherry growers.
The initial cost was a barrier for some farmers. “Of course, mosquito nets are a bit more expensive than insecticides,” admits Etienne.
The cheaper Texinov nets about €0.50 (44p) per square meter for private use in France, according to Etienne. This type of netting only lasts one or two seasons, although heavier climate protection nets can last longer. Durability depends on factors such as sun exposure. “The webs are becoming more fragile because of the sun,” says Etienne.
In general, Professor Aoun says, prices go down as the variety and accessibility of products increases. And she sums it up: “Overall, the positive effect of the network outweighs the negative.”
Jean-Marc Rochon heads the Pépinière Rochon apple tree nursery in Quebec and monitors developments in the netting field.
“In my view, this technology is more in the development and improvement stage than in large-scale application,” he says.
For Mr. Rochon to start using nets on his apple trees, the cost of netting would not be the only factor. “I see it more as a way to rethink our ways of doing things,” he explains.
To be viable in the nursery, the net must be reliable and not cause an overload in the work. It should also be usable in larger orchard sections.
Obviously, improvements in technology and communication will be necessary to convince more fruit growers that netting will be beneficial.
But Prof. Aoun believes, “As we move towards more climatic challenges and unpredictable weather, preventative cultivation with netting is the way forward.”
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