Innovative water droplet techniques boost disease resistance in crops
In the latest research published in the esteemed "Journal of Agricultural and Food Chemistry," scientists highlight the relationship between the size of water droplets used in spraying plants and their growth and resistance to pests and disease. This is not an insignificant factor.
Agriculture is facing serious challenges with ongoing climate changes affecting the destabilisation of rainfall patterns and rising temperatures. Therefore, it is essential to seek alternative, more ecological solutions that will enhance crop health without increasing the volume of chemical pesticides.
Experiments on tomatoes: Differences between droplet sizes
A group of researchers from Huazhong Agricultural University in Wuhan, led by Man-Qun Wang, conducted experiments on tomato bushes to investigate how mechanical stimulation in the form of water spraying influences plant growth.
Researchers particularly focused on two sizes of water droplets: small, with a diameter of 200 micrometres, comparable to a pixel on a computer screen, and large, measuring 1000 micrometres, equivalent to the diameter of a pinhead.
To maintain full control over the study, the soil beneath the bushes was covered with an impermeable coating, eliminating the possibility that water reaching the roots could influence the experiment's results.
The findings were surprising. Plants sprayed with larger water droplets were shorter and more compact than those that received smaller droplets or were not sprayed. Interestingly, the differences in the quality and quantity of fruits between these three groups were slight. However, what distinguished the plants exposed to larger droplets was their increased resistance to pests and diseases, including cotton bollworm (Helicoverpa armigera) and grey mould (Botrytis cinerea).
Increased resistance of plants sprayed with larger droplets
Metabolic analysis revealed that the bushes sprayed with larger water droplets had elevated hormones responsible for plant defence responses. Researchers also noted higher levels of chlorogenic acid in the leaves, further bolstering plant resistance.
Moreover, there was a reduction in the emission of volatile organic compounds, which typically attract butterflies that lay eggs on plant leaves. As a result, the number of eggs laid by insects decreased by 74 per cent compared to unsprayed plants.
In light of these promising results, the study's authors suggest that the advancement of water spraying technology could improve agricultural practices, making them more ecological and effective. Mechanically stimulating plants, for instance, through appropriate spraying, could serve as an alternative to using pesticides while supporting crops' natural defence mechanisms.
This study represents another step in discovering methods to help agriculture adapt to increasingly challenging environmental conditions while minimising the negative impact on the natural environment.
