|Biologist Juan Manuel Vanegas-Rico|
|Photo by J.A. Cruz-Rodríguez|
A prickly pear plantation in Axapusco,
Estado de México, México.
"Scale insects known as cochineals are major pests of prickly pear in Mexico, and pesticides are often used to control them. However, one prickly pear farmer has been controlling them without the use of insecticides since the year 2000."
"The farmer tipped off a team of scientists from the Universidad Autónoma Chapingo, and he told them that other insects were feeding on the scale insects. The researchers decided to investigate, and they found that the farmer was right. During the entirety of the research, the abundance of scale insects never reached pest status. Furthermore, when populations of scale insects increased, populations of predators increased at the same time, therefore regulating the growth of the scale insect populations. Their observations are described in an article in Environmental Entomology
"During the entirety of the research, the abundance of scale insects never reached pest status."
"The farmer originally thought that ants were controlling the cochineals, but it turned out to be other insects. Six known predators of cochineals were found on the plantation, including different species of beetles, moths, lacewings, and flies — but no ants."
"This finding is important because the two most common ways to control scale insects in prickly pear in Mexico are 1) to use organophosphates, a class of insecticide that Mexican regulatory agencies do not recommend for this use, or 2) to knock the insects off of the plants using mechanical brooms. This study suggests there might be an alternative: natural control as a result of biodiversity, also known as
|Photo by J.A. Cruz-Rodríguez|
Colonies of scale insects (Dactylopius opuntiae)
on fruits of a prickly pear (Opuntia megacantha)
"However, Dr. J. A. Cruz-Rodríguez, an author on the paper, warns that this method of control isn’t necessarily one that can be applied at will to other plantations or 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 other words, a lot of conditions must be met in order for
autonomousself-governing control to be viable."
"Autonomous control requires an ecological infrastructure that supports a network of interactions that limit the explosive growth of herbivores,” Cruz-Rodríguez said. “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.This study shows that if the conditions are right, farmers can potentially use natural predators for autonomous control."This last paragraph really says it all and actually allows for the door for biocontrol for other crops to remain open. Not only scientists, but anyone should proceed and experiment on their own as a sort of what is being called a "citizen scientist" and share successful results with others. Believe it or not, professional researchers learn very much from people considered layman who have a natural passion for a specific phenomena found in Nature. Remember, even in healthy forested environments where all vegetation looks perfectly healthy, the insects and plants otherwise considered pests or weeds are still present, but their numbers are kept in check through a complex infrastructure of biological controls. Learning what those are can be fun and rewarding. Now let's look below at some information about this white scale insect you probably never knew. Did you know that in many places around the globe like Mexico and Iran, they are farmed for their red dye ingredients potential for the fabrics industry ? Below is a photo of an Iranian Cacti plantation which has these little baskets attached to prickly pear pads. Click on the link below the photo of an Iranian website in English which goes into great deal on how this so-called pest is an income earner for some Iranian Farmers.
Farming Cochineals scale insects (Dactylopius opuntiae), for their raw material for the manufacture of Red dye
"Cochineals are farmed in the traditional method by planting infected cactus pads or infecting existing cacti with cochineals and harvesting the insects by hand. The controlled method uses small baskets called Zapotec nests placed on host cacti. The baskets contain clean, fertile females which leave the nests and settle on the cactus to await insemination by the males. In both cases the cochineals have to be protected from predators, cold and rain. The complete cycle lasts 3 months during which the cacti are kept at a constant temperature of 27 °C. Once the cochineals have finished the cycle, the new cochineals are ready to begin the cycle again or to be dried for dye production."
"To produce dye from cochineals, the insects are collected when they are approximately ninety days old. Harvesting the insects is labor-intensive as they must be individually knocked, brushed or picked from the cacti and placed into bags. The insects are gathered by small groups of collectors who sell them to local processors or exporters."
"As of 2005, Peru produced 200 tonnes of cochineal dye per year and the Canary Islands produced 20 tonnes per year. Chile and Mexico have also recently begun to export cochineal. France is believed to be the world's largest importer of cochineal; Japan and Italy also import the insect. Much of these imports are processed and reexported to other developed economies."