Environment: An innovative biopesticide ally of bees is coming from ENEA

ENEA, in collaboration with the Experimental Zooprophylactic Institute of Southern Italy, has developed an innovative biopesticide that protects bees, exploiting molecules that exert natural control on infesting organisms.“Over the past 10-15 years, European beekeepers have reported an unusual decrease in the number of bees and colony losses, particularly in Western European countries, including Italy. A phenomenon that has several causes, such as intensive agriculture, the use of pesticides, habitat loss, viruses but also attacks by pathogens and invasive species such as mites Varroa destructor, for years present throughout Italy ", explains Salvatore Arpaia, researcher of the ENEA Division of Bioenergy, Biorefinery and Green Chemistry. “The Asian hornet has recently been added to this last species - continues the researcher - Vespa velutina and the little hive beetle Aethina tumida which, at the moment, has a territorial diffusion limited to the southernmost part of Calabria. And we tested our innovative biopesticide in this region, at the section of the Zooprophylactic Institute of Reggio Calabria, where the beetle is kept on the farm subjected to stringent containment measures ".

The interfering RNA technique, which exploits a natural mechanism present in plant and animal organisms to lead to the loss of functionality of a target gene, essential for the survival or fertility of the insect. "The results obtained clearly indicate that the administration by ingestion of our biopesticide, which uses the action of specific double-stranded RNA molecules against two genes of Aethina tumida, induces anti-metabolic effects on the development and reproduction of the beetle. In fact, the larvae fed with a diet containing the molecules that we synthesized in our ENEA laboratories in Trisaia, Basilicata, suffer from a decrease in the rate of development, a slowdown in the biological cycle and, as adults, a significant reduction in fertility. The coexistence of these three effects in a population in nature leads to a foreseeable rapid containment of the damage of the beetle to the hive, to the beekeeping production, without any risk for the environment and for man ”, emphasizes Arpaia.

"As regards the protection of the health of bees subjected to treatment with a dsRNA-based insecticide, a first evaluation was made with a similarity analysis of the sequences between the two dsRNAs used and the genome of Apis mellifera, which is completely sequenced. The very low similarity revealed by the BLAST analysis[1] leads to the exclusion of any effects due to the sequence used. To evaluate the possibility of effects off-target on bees, it will be necessary to carry out a subsequent in vivo test, even if the evidence available in the literature referring to other dsRNAs indicates that the bee is generally not very sensitive to the gene silencing induced by the molecules we have used ".

The small hive beetle is a family insect Nitidulidae and of the order of the Coleoptera, infesting the colonies of Apis mellifera. It is a species native to South Africa and endemic to the tropical and subtropical regions of Sub-Saharan Africa; was found for the first time in Europe, in Calabria, in September 2014. The insect is included in the list of the Health Code for terrestrial animals of the WOAH (World Organization for Animal Health) as an emerging pathology of bees and is subject to international notification. Furthermore, it is included in Annex II of the EU Reg. 429/2016 which establishes the obligation of notification and measures for eradication. To contain its spread in Europe, important restrictive measures are in place that involve the cessation of nomadism (including the significant work of support for pollination in fruit growing), the trade of colonies outside the area infested by the beetle, periodic monitoring hives and, in many cases, the destruction of colonies.

Salvatore Arpaia, ENEA - Bioenergy, Biorefinery and Green Chemistry Division,

[1] BLAST (Basic Local Alignment Search Tool) is an algorithm  to compare information contained in primary biological structures, like  protein sequences or  nucleotide sequences of DNA molecules.