Prickly pear farmer demonstrates how to grow food without noxious pesticides

Thursday, May 19, 2016 by: S. Johnson
Tags: pesticides, autonomous control, natural alternatives

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(NaturalNews) Scale insects known as cochineals are a major problem for prickly pears in Mexico, and are commonly treated with noxious pesticides. Contrary to popular belief, however, chemical pesticides that are just as damaging to human health as they are to insects aren't necessary for bug control. A prickly pear farmer has been able to combat cochineals without the use of insecticides since the year 2000, and he recently let a team of research scientists in on the secret.

So what is the secret? The farmer informed a group of scientists from the Universidad Autonoma Chapingo that other insects were feeding off the scale insects. The researchers probed further into the farmer's claim, and found that other insects were indeed feeding off the scale insects. Over the course of the study, the number of scale insects never once reached the level of pest status. Whenever the cochineals population increased, the population of predators increased as well, which helped maintain the growth of the scale insect population. Their findings were recorded in the journal Environmental Entomology.

The study was performed on a nopal plantation that cultivates fruit known as "tunas" in Mexico, close to the archaeological site of Teotihuacan. Fruit production starts in February when flower buds flourish, and ends in August once the fruits are harvested. The farmer estimated that he harvests around six tons of fruit each year.

Estimating the density of the cochineal population

In order to estimate the density of wild cochineal, the researchers collected a random sample of 609 cladodes, a flattened leaf-life stem, that were obtained from another random sample of 52 plants. The team regarded each body as a colony of cochineal, and the entire colony in a single cladode as a cluster. Between August 2012 and November 2013, cladodes were collected from plants with different levels of infestation of cochineals.

The cochineal were present in the plantation over the months with different density averages. The highest average density in the review was in August 2012. Some cladodes and fruits with high levels of infestation were observed, and had a number of colonies that coated up to 75 percent of their surface, the researchers noted.

Upon studying the plantation, the researchers found that the density of infestation was consistently below pest levels. The farmer reports that this condition has stayed stable for over a decade. Although he does not use pesticides, the presence of cochineal has not posed a risk to fruit production.

The team found that the population of cochineal was directly related to the increase in the number of predators in cladodes with more colonies. The farmer originally believed that ants were maintaining the cochineal population. In actuality, the cochineal population was controlled by a range of other predator insects, including beetles, moths, lacewings and flies, but ants did not make the list.

Autonomous control as an alternative to synthetic pesticides

The results of the study suggest that natural control, otherwise known as autonomous control, is a viable alternative to chemical insecticides which, in addition to killing insects, have been linked to a myriad of health problems in people, including cancer, nerve damage and hormone disruption. Nevertheless, Dr. J. A. Cruz-Rodriguez, one of the co-authors of the study, cautions that this technique might not work for all plantation crops.

"Autonomous biological pest control cannot be considered a technology that is applied or not depending on the level of the pest," he said. "It is a process that is established and maintained if the agroecosystem retains structural complexity and diversity of species."

In layman's terms, there are a lot of environmental variables that must be fine-tuned in order for autonomous control to work.

"Autonomous control requires an ecological infrastructure that supports a network of interactions that limit the explosive growth of herbivores," Cruz-Rodriguez said in a press release. "Intercropping, agroforestry systems, non-use of biocidal products (or its more rational application) -- they all contribute to the formation of the biotic network that prevents the development of pests."

Sources include:

EurekAlert.org

EE.OxfordJournals.org

EntomologyToday.org

Science.NaturalNews.com