The University of Granada has carried out a study with the biological control group of the Andalusian Institute of Agricultural Research and Training, Fisheries, Food, and Organic Production (Ifapa), and researchers from other institutions, to evaluate the effect of artificial sugar supply on ant-aphid interactions in protected horticulture.
This groundbreaking work, which represents a significant advance in the field of biological aphid control in greenhouses, aims to test the hypothesis that providing ants with high-quality sugar should stop them from tending to aphids in the greenhouse and start preying on them.
Ants tending aphid colonies may reduce the effectiveness of aphid natural enemies, a control method widely used today by farmers in protected horticulture. This can lead to difficulties in controlling the pests and having to resort to the use of insecticides with the consequent risks this implies, including the marketability of the crop.
However, the ant-aphid mutualistic interaction is complex and, depending on the quantity and quality of sugar produced by aphids and other sources, ants may switch from caring for aphids to preying on them.
To this end, researchers have carried out experiments on pepper plants infested with the Aphis gossypii Glover aphid in four greenhouses with the natural presence of the Tapinoma ibericum Santschi ant in three periods and two different years.
The results of the experiments show a significant reduction in aphid abundance and increased aphid predation by ants on plants with artificial sugar supply.
However, the expected effects varied between greenhouses and seasons, with a significant decrease in aphid abundance detected mainly in autumn, while the greatest effect on aphid predation by ants was detected in summer, when ant activity on the plants was lower.
In addition, even though the results show that the artificial supply of sugar changes the ants' behavior from caring to predating aphids, the large variation observed indicates that other factors that haven't been considered influence its effectiveness. Thus, future research is needed to understand the factors driving variation between locations and seasons.
In addition, the researchers have detected in Almeria that the effect of sugar supplementation and its disruption of the ant-aphid mutualism could improve the access of biological control agents frequently used by greenhouse farmers to aphid colonies, an aspect that could be evaluated in future research work in this direction.
The study, published in BioControl, the official journal of the International Organization for Biological Control (IOBC), can be accessed at the following link:
https://link.springer.com/article/10.1007/s10526-024-10294-x
For more information:
Francisca Ruano Díaz
University of Granada
Tel.: + 34 958 241000 ext 20064
Email: fruano@ugr.es