Above: Members of the long term group
More than a quarter of overall agricultural yield is lost to insect pests. The main way these losses are curbed is through use of insecticides, but these pesticides are harmful to humans and the environment, expensive, and only provide short term protection. Insect pests can have much larger populations in agricultural settings than in their natural environments. This is often due to their natural enemies, such as predators and parasites, that are less common in agricultural plots.
Biological control is the practice of introducing, augmenting, or supporting naturally occurring enemies to suppress pests. It has been a spectacular success in many cases but not always. Success depends on the selection of the right enemy species, the mode of introduction, enemy compatibility with the environment, and farming practices. For instance, if insecticides are also used then the natural enemy can be killed along with the pest and the pest may soon resurge.
People have benefited from biological control since agriculture began. Designing effective methods is a continuing challenge as new insect pests emerge, agriculture develops and is globalized, climate changes and insects can invade new areas.
Biological control is essentially a manifestation of ecological processes in an agricultural setting, so ecological theory, much of which can be expressed using mathematical models, can be used.
Michal Segoli, Jacob Blaustein Institutes
for Desert Research, BGU, Tamar Keasar (University of Haifa), and Eric Wajnberg (INRAE, France) assembled an international group of a dozen ecologists and entomologists who just completed five intensive months of work to look for solutions to both theoretical and practical problems in biological control. They formed the research group Mathematical Modelling of Biological Control Interactions to Support Agriculture and Conservation at the Israeli Institute for Advanced Studies.
The group focused on five important topics that will benefit biological control when considered in an ecological context:
- Predicting the potential success of organisms as natural enemies based on their biological characteristics
- Quantitative accounting of the overall risks and benefits of biological control introductions to native biodiversity
- The role of landscape structure and the movement of pests and enemies in the effectiveness of biological control
- The impact of climate change on the effectiveness of biological control
- The interplay of insecticide application and the performance and persistence of natural enemies
The group used theory to explore, for instance, if global warming will cause insect communities to become less complex leading to increase or decrease in biological control effectiveness.
The group also worked towards practical solutions to specific problems for Israeli farmers, such as devising decision rules for pesticide application in tomatoes based on the presence of natural enemies in the field, guiding biological control of pests in grain storage, and prioritizing locations for effective, area-wide control of orchard pests.
The group's tenure at the Israeli Institute for Advanced Studies culminated over the past two weeks in a workshop teaching modeling to graduate students in the fields of agroecology, conservation, and plant protection, followed by a three-day 50 delegate international conference on bridging the gap between ecological theory and biological control.
Long-term fellows (pictured above):
Tamar Keasar (University of Haifa, Israel),
Michal Segoli (Ben-Gurion University of the Negev, Israel)
Eric Wajnberg (INRAE, France)
Moshe Coll (Hebrew University, Israel)
Asaf Sadeh (Newe Ya'ar Research Center, Israel)
George Heimpel (University of Minnesota, USA)
Saskya van Nouhuys (Indian Institute of Science, India)
Ian Hardy (University of Helsinki, Finland)