The thripid is a pest insect dreaded by horticulturalists . Rob van Tolhas designed a trap for catching the insect using light-emitting diode light . Butwhat scant composition are they most attracted too ? It turned outthat Dutch and German thrips have different ideas about that .
In the giant greenhouse at the chrysanthemum nursery G&C Flowers in Gameren , the Wageningen bug-hunter Rob van Tol display a regular hexahedron . This is the image for a new generation of insect traps that he is going to test here on thrips , a pest that causes equipment casualty to a range of crops , from cut flowers to courgettes and ship’s bell peppers . The hope is that he has found an alternative to the savourless , coloured gluey boards that many cultivator still utilise to monitor and see their pest . ‘ Of the thrips that are attracted to a coloured circuit card , only between five and 15 per centime actually set ashore on it . The rest escape cock . Why is that ? Apparently there is something incorrect with the trap . The insects issue forth towards it , but once they get close they lose their way and get disoriented . The few that do demesne are the “ gatecrasher ” , the also-ran who more or less crash into it . ’
The sticky control board are utilitarian for monitoring worm but not really for get them in large turn . And yet that must be possible , think Van Tol . ‘ really , so far all the enquiry on insect trap has mainly been empirical . The whole spectrum of colours has been studied for attraction to insects but no one has go into it in greater profundity . What do dirt ball actually see ? How do they orientate themselves , and which aspects play a role in that ? I want to use that basic cognition to produce good traps , the kind that louse do decide to land on . ’
Causing damageSeveral species of thrips are found in Dutch greenhouses . Horticulturalists currently fight them by setting natural enemies such as assassin bugs on them , or by spray them with – increasingly ineffectual – pesticides . With funding and support from the horticulture governance LTO - Greenhouse Horticulture , Koppert Biological Systems , Lincoln University in New Zealand and the Horticulture Top Sector in the Netherlands , Van Tol has been working for over two years on what he has begun to see as his life ’s body of work : the light-emitting diode trap for the extremely destructive Californian thripid . His prototype is the regular hexahedron which consists of eight section , each of which can be fall up separately with light-emitting diode luminosity of different colours and grade of intensity , and with combination of these .
In a wind tunnel , Van Tol tested the behaviour of thrip when exposed to lead light in this palette of colours . Two infrared cameras made it possible to tape the itinerary of each insect in 3D. This setup has already delivered some remarkable finding . One model : thrips always go about a trap from downwind . Van Tol : ‘ They always land against the wind . They can vaporize with the wind in their back , but they ca n’t bring . So they fell past the trap and release to fly into the wind . ’
predilection for yellowThis may seem a trivial head , but it is not , says Van Tol . ‘ This is important for designing a well insect gob . The trap must not be flat but three - dimensional so that it is possible to bring on it from all side . That get the trap more efficient . ’ It also transpired that thrips prefer yellow light to blue . Which is interesting , collapse that dark boards are often used to entice the worm in greenhouses . Moreover , German research worker find a preference for gentle , and this held even when the German thrips were essay in Wageningen . ‘ The insects oppose in the same path as in Germany , suppose Van Tol . ‘ So it was not due to a difference in the experimentation . It is also clear that the host plant on which the thripid are bred play a limited theatrical role . Another account might be hereditary deviation between the two mob of thrips . ’
To get to the bottom of this , a new series of tests using the LED cube is plan to study the effect of all the possible combinations of yellowed , blue , UV and light-green light . And to complicate affair even more , the hunger factor might play a purpose too sometimes , says Van Tol . ‘ Thrips flee towards xanthous because they are athirst and they cerebrate it is a flower they are go out . But a thrips that is n’t hungry might be take up towards blue . So perhaps you demand several colouration to get all the thrips . We can figure all that out with the new light-emitting diode trap . ’
Besides colour and line , design play a role in the orientation . Van Tol demonstrate us his late toys : LED lights that grow a pattern of homocentric roundabout , stripes or dots . The researchers are pulling out all the stops to make the insects into landing place . Researchers at Lincoln University working for the Wageningen thrips project on a field of study of how the insect ’s eye works ( see gusset ) . The bearing is for the insect trap of the future tense to be the pure hook .
root : Wageningen World
