Encouraging results have been achieved in Eastern Friuli in the fight against harmful insects, thanks to agronomic best practices aimed at increasing plant biodiversity in vineyards. Antonio Noacco, an agronomic consultant, along with a diverse team of collegues, in collaboration with the University of Udine, conducted the Biodiversity Care project in the vineyards of Annalisa Zorzettig’s estate, aiming to prove the effectiveness of biological pest control through the increase of predatory insects and other beneficial organisms in vineyards managed with alternated mowing and cover crops.
“When Antonio Noacco proposed conducting part of the experimentation in our vineyards, we didn’t hesitate to give him full support,” explains Annalisa Zorzettig. “The results confirmed how our commitment to environmental sustainability is well rewarded. Even the new winery, nearing completion, will have the planting of native species all around to promote functional biodiversity.”
The three-year study focused on various theses to examine the effects on beneficial arthropods in vineyards and their effectiveness in combating harmful insects, such as the red spider mite and the scale insect, particularly worrying Friulian winegrowers and also considering future concerns. The study unfolded in three phases: evaluating the effects of practices aimed at increasing plant biodiversity in rows, specific research on combating the scale insect (Planococcus ficus), and botanical analysis.
Field trials in Zorzettig’s vineyards in Friuli have demonstrated the effectiveness of plant biodiversity for biological pest control against harmful insects
The main theses compared traditional agronomic management practices such as continuous mowing to practices aimed at increasing the number of plant species and the consistency of spontaneous and seeded blooms. The timing of the three years (2019-2020-2021) was crucial to observe population behaviors over generations, as the life cycles and reproductive cycles of some insects and organisms can span a year.
While in 2019 the three vineyards had almost similar behaviors, significant results were observed from the second year onwards.
For example, in the completely mowed vineyard, the presence of the grape leafhopper (Empoasca vitis) was more than double that of the vineyard with alternate mowing (300 specimens per 400 leaves compared to 150), and triple that of the vineyard with cover crops.
The same result was observed regarding the incidence of scale insect infestations (Planococcus ficus). This effect was due to the greater presence of calcareous hymenoptera, natural parasitoids and primary agents of biological control, which, finding greater feeding opportunities in blooming vineyards (pollen and nectar), were able to reproduce more effectively and their action was more impactful.
Furthermore, it was proven that where complete mowing occurred, alien plant species had occupied a larger area, limiting the growth of native species and their abundance. Conversely, the opposite trend was observed in the unfazed rows, indicating a stable and healthy ecosystem. This data is important both in terms of increasing species richness and in reducing the use of water and nutrients needed by native species.
For this reason, the next phase of the study will focus on soil, the microbiome, and consequently, fertility to assess the impact of virtuous agronomic practices on the solidity of the biological/vineyard ecosystem.