By Vicky Just
Scientists at the Universities of Bath and Sussex have developed a new system that slowly releases ant pheromones to attract pests to an insecticide bait. This means that instead of spraying the whole crop with pesticides, traps can be placed in specific areas for more targeted protection.
Leaf-cutting ants are major pest species of agriculture and forestry in many areas of the tropics causing an estimated $8 billion damage each year to eucalyptus forestry in Brazil alone.
Traditional pesticides often degrade quickly and are not specific to particular pests, resulting in substantial wastage of pest control products, environmental contamination and harmful effects on other insects.
The team of chemists and chemical engineers at Bath used molecular sponges called metal-organic frameworks (MOFs), to soak up the alarm pheromones of leaf cutter ants and then slowly release them to attract the insects to a trap.
In addition to experiments, they used computational modelling to simulate the movement of the pheromone molecule inside the pores of the MOFs to predict which structures would give the optimum capacity and speed of release.
They found that by altering the chemical groups within the basic framework structure, they could adjust the speed of release of the pheromones so that the chemicals could be released over a period of several months rather than days.
Field trials of the system by University of Sussex researchers in a eucalyptus plantation in Brazil showed that the pheromone-loaded MOFs had the desired effect in attracting the ants to a trap.
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