A research team has developed a new glue spray made from edible oils to trap plant pests as an alternative to synthetic pesticides, The Guardian reported.
Conducted by researchers at Wageningen University & Research (WUR) in Germany and Leiden universities in the Netherlands, the results were published in the scientific journal Proceedings of the National Academy of Sciences (PNAS), the 18 May report said.
Using a technique used by plants such as sundews to capture insects, the sticky edible oil droplets trapped pests without the use of synthetic pesticides when sprayed on crops, The Guardian wrote.
In a similar process used in deep frying, the researchers oxidised vegetable rice waste oil to make it as sticky as duct tape and then mixed it with water and a small amount of soap to stop the droplets sticking together.
The drops were trialled on the common pest insect Frankliniella occidentalis (thrips), which have been known to attack more than 500 species of vegetable, fruit and ornamental crops.
The solution was sprayed on the leaves of chrysanthemum plants, the thrips’ favourite food and a major commercial crop in the Netherlands and was also tested on strawberries.
During the two-day testing period, more than 60% of the thrips were captured and the drops remained sticky for weeks.
The sprayers used were the same design as those currently in use and field trials later this year would test the process at scale.
Work on the sticky pesticide was ongoing, Dr Thomas Kodger, associate professor of Physical Chemistry and Soft Matter who was part of the research team at WUR, said.
The team was testing to see if scents could be added to the droplets to make them even more attractive to thrips or to attract natural predators of the pests.
The WUR and Leiden researchers have applied for a patent to set up a spin-off company – expected to start by the end of this year – to commercialise the new pesticide with a focus on using a range of waste oils.
By making small adjustments to the process, any type of vegetable oil could be used to make the pesticide, the researchers said.
Although some farmers used alternatives to chemical pesticides, such as introducing other insects to kill pests, the new sticky drops were believed to be the first biodegradable pesticide to be demonstrated, The Guardian wrote.
Pests were also highly unlikely to evolve resistance to physical pesticides, as this would require them to develop larger and stronger bodies, while the millimetre-sized drops were too small to capture bigger beneficial insects, such as pollinators.
The cost of the sticky drop pesticide was uncertain as it was not yet known how much would need to be applied and how often, the report said.
Nick Mole, from Pesticide Action Network UK, was quoted as saying: “This … research … could result in much-needed decreases in the use of synthetic pesticides. Using natural oils to make physical traps for disease-carrying insects could be a sustainable alternative to toxic pesticides.”
However, Mole said more research was required to assess the impact on the environment and non-target insect species.