The research, carried out at the University of Bristol, the Food & Environment Research Agency and the University of Western Australia, and published last week in the online journal PLOS ONE, could open up a new field of research to improve crop health, according to the authors.
Co-author Professor Gary Foster said: "Much of the historical work carried out has been within the visible wavelengths of light. However, we know insects can see polarised light regions, and this research shows that plant virus infection can affect the percentage of polarisation of light reflected from leaves, meaning bugs such as greenfly have the potential to 'see' which plants are infected."
Photographs taken using a polarising filter revealed that leaves infected with potato virus Y or cucumber mosaic virus were significantly less polarising than healthy leaves, due to properties of the waxy outermost layer of the leaf cuticle, while other non-insect vectored viruses showed no such effect. Indeed, changes were found in the gene expression patterns of these wax genes in plants infected with aphid-vectored viruses. Previous studies have shown that plant viruses can also change plants' smell.