Predatory insects are beneficial for the farm

The vermin pests cause millions of dollars to farmers every year and are the cause of the widespread use of chemical pesticides, which eventually become immune to the this medicine.

However, an effective, clean, environmentally friendly and long-lasting solution is the use of wasps, flies, flies, ladybirds and other predators that often feed on plant pests. .

Scientists and farmers are finding ways to more effectively use this 'beneficial' weapon by changing landscapes to create a suitable habitat for plant-eating insects, encouraging them. nest or house on farms.

Rebecca Chaplin-Kramer, a PhD at the University of California, Berkeley, published the results of last week's 'biocontrol' study at the American Ecological Society's annual meeting in Albuquerque, New Mexico.

Extending and encouraging habitats for insectivores does not work immediately for the use of pesticides, but it has a long-term effect, because insectivorous species or groups can Development continued, Chaplin-Kramer said.

Using this method also saves costs. The US Environmental Protection Agency estimates that farmers use more than US $ 30 billion per year for pest control - and that costs are still rising.

However, insects still fail more than 1/3 of the potential crop. In addition, more than 500 plant pests can resist the chemicals used to control them.

Species hunt insects

Previous studies have shown that diverse topography is a premise for larger predator communities. But it is difficult to assess the impact that farmers really care about: the ability to control the pests of plants.

Chaplin-Kramer is hoping to resolve this question.

She has worked in California's Salinas Valley since 2006, assessing the ability of predator communities to control crop pests within the farm and surrounding areas.

Chaplin-Kramer specializes in the study of cabbage aphids, the disease of many broccoli crops and the prey of syrphid flies.

She first surveyed some experimental farms that mixed plants with hedgerows, weeds, and even strips of flowers or plants designed to attract predatory insects. Other locations only have rows of broccoli trees.

However, the assessment of the role of habitat on pest control may be difficult, as a number of factors, such as weather changes, can affect the number of aphids that appear. in a field.

An effective, clean, environmentally friendly and long-lasting solution is the use of wasps, flies, flies, ladybirds and other predators that often feed on plant pests. (Photo: NationalGeographic)

She explained: ' Surveys don't really tell the whole picture. If a location has fewer pests, is it predatory or simply they do not appear? '

Chaplin-Kramer placed broccoli plants infected with aphids in open and closed cages. Open cages allow natural predators to control pests, while closed cages allow aphids to live or die depending solely on environmental conditions.

These cages are placed in many different environments from natural and diverse environments to monoculture fields.

The results show that the ability to control pests is significantly improved as predator communities grow in natural areas around a field. Without the surrounding natural area, farmers can still gain the necessary benefits by forming complex fields.

'Natural terrain shows that the ability to control pests is five times more than the agricultural terrain at the beginning of the season,' Chaplin-Kramer said.

'At the end of the season, in agricultural areas, more diversified cultivated farms have four times more pest control than simple farms'.

The study also found that insect hunters often go to farms a little later in the growing season. This suggests that farm environments may be early-stage aphid control factors, and pesticides or measures that may be needed to prevent pests from achieving reversible advantages.

At the same time, the ability to control the most friendly terrain of predatory species can be adversely affected by natural factors, such as temperature and humidity.

You farmer?

These results draw a promising but also complex scenario, as many farmers say.

Phil Foster, who runs Pinnacle Organics in San Juan Bautista and Hollister, California, worked with Chaplin-Kramer in this study. He often planted 30 or 40 different plants. He also rotated plant varieties and planted predatory tree fences

He said: 'I found that the entire farm system is quite important. We are in the 20th season of organic produce, and for us it is always a continuous learning process. '

Foster's lettuce wing is an example of how he makes insect pests feel at home.

He said: 'It is possible that 5 to 8% of the area is devoted to plants such as fennel and coriander plants, which are capable of attracting beneficial insects such as adult syrphid flies and wasps parasites'.

Foster did not harvest these herbs but planted them only to attract vermin-hunting species - although he also considered the possibility of combining fennel and cucumber to produce pickles.

Steve Stevens, a cotton farmer faced aphids, though not running an organic crop base but also dependent on natural sources for controlling pests.

'We tried not to spray until we had to,' he said, 'because we keep the beneficial insects for as long as possible.'

Stevens hypothesized that for him, predatory insects provide a way to enhance 'resilience management'.

'If we continue to abuse some pesticides, the pests will be resistant to that pesticide'.

The solution is not comprehensive

The drawbacks of pesticides are the reason biological control attracts attention, according to Robert Wiedenmann, head of the University of Arkansas entomology department.

He added: ' At the same time, there is no general consensus on biological control, because there is still no general knowledge about this area. This is not an easy-to-understand method and application, thus limiting its many features'.

However there are also some downsides.

'Many natural enemies, especially insect parasites, are usually quite specific. They will not benefit all pests, a benefit they are similar to what a pesticide can provide. A very beneficial habitat when dealing with aphids may have no benefit when dealing with worms. '

That is why Wiedenmann emphasized that biological control, although very promising, is not a comprehensive and thorough solution.

However, he believes it can be an important solution in the long run, potentially creating a farm environment with the ability to control natural pests that operate each season.

He concluded: 'The future of integrated pest control will not only rely on pesticides, or wait for problems to arise before trying to find a solution'.