Mexican researchers have developed a biological control against leaf-rolling weevils that not only has potential to improve avocado crops, but leaves no chemical residue, reported science news website Agencia ID (www.invdes.com.mx).

The story reported that many avocado-importing countries do not buy Mexican avocados because they carry chemical residues, but recent research from Mexico’s National Polytechnic Institute (INP) could solve this problem.

The research was conducted by INP’s Genome Biotechnology Centre (CBG) and led by Dr. Ninfa Marí Rosas García. She said the study used substances with bacteria that kill the weevils, but are not harmful to humans and don’t pollute the environment.

“We proposed the development of a biological insecticide that was biodegradable in the environment, didn’t cause any damage, coupled with the fact the fruit could be exported without any pretext,” she was quoted as saying.

“Therefore, we took on the task of finding endemic bacteria in the regions of Michoacán and Nayarit, avocado-producing zones to see if we could find one that is efficient and controls the leaf-rolling weevils.”

The website reported that CBG used a strain collection called Bacillus thuringiensis, which has a high grade of toxicity against the insect, and with this active ingredient the biodegradable insecticide was developed. The product comes in a form of powder that can be mixed with water and applied with a bag spray.

The investigation recorded successful results over an area of three hectares in Nayarit, but the formula is still undergoing the patenting process.

García told Agencia ID  it is recommended the insecticide be applied when a plague lays its eggs in the tree leaves.

Photo: www.fao.org

Source: www.freshfruitportal.com