Trap systems for catching insects in greenhouses and in the field are not as effective as they should be. The probable cause is that insects cannot see the current designs very well and do not land directly on these traps. Basic research is underway to pave the way for more effective trap systems and less use of chemical pesticides.
“There is currently very little fundamental research being conducted into the effectiveness of trap systems in greenhouses and in the field,” says entomologist Rob van Tol of Wageningen University & Research. “What we do know mainly stems from comparative research: we see that a given system captures more bugs than another due to different circumstances. But if we look at the effectiveness, usually only 10 to 15% or even fewer of the insects present actually land in a trap. Many insects do get lured to the trap with scents, but change course at the last minute. This can be compared to a runway without proper markings, where the pilot cannot perceive depth and takes off again.”
The international research project ‘Are more visible traps more effective?’ will, over the coming few years, answer the question of how insects detect objects. The fact that trap systems only partly work seems to be due to the exact way in which insects see colours, patterns and objects, as Van Tol explains: “An insect eye is composed of many separate tiny lenses, each of which has its own limited scope. We want to assess how bugs see and what they see. Next we can look at how they use their visual ability to orient themselves and decide whether or not to land on an object.”
European tarnished plant bug and Western flower thrips
The research focuses specifically on two notorious pest insects: the European tarnished plant bug and Western flower thrips. Van Tol expects that the project may provide a breakthrough: “If we know how an insect perceives differences as it approaches an object, we can develop models for effective trap systems. We are, as it were, looking to design the perfect runway to capture harmful insects.”
Better traps leading to fewer chemicals
If Van Tol and his colleagues succeed it will offer major opportunities for producers of trap systems. “Better traps on the market would ensure better monitoring but also more insects will get contaminated with insecticidal fungi in a so-called ‘Lure & Infect’ strategy. We can also simply trap insects en masse and render them harmless, effectively culling them and leaving much smaller numbers to affect the crop. This means far fewer chemicals would be needed to combat the pests and, in that sense, the project would contribute to a more sustainable agriculture.”
In this study, Wageningen University & Research has teamed up with the Lincoln University in New Zealand and Lund University in Sweden. LTO Glaskracht, Koppert BV and the Dutch top sector Horticulture and Propagation Materials are co-financiers.