How insects find out diseased plants

The leaves of virus-infected plants reflect light differently to attract the attention of disease-spreading greenfly, new research suggests.

Plant viruses alter the surface of leaves, influencing how light is polarized and thereby helping insects to potentially 'see' infected plants, the findings showed.

The majority of vector-transmitted plant viruses are spread between host plants by insects, in particular by sap-sucking aphids -- more commonly known as greenfly -- which are thought to be sensitive to polarization patterns.

The research, published in the journal PLOS ONE, could open up a new field of research as plant scientists hope to solve some of the major threats to global food security.

"Transmission of plant viruses by insects is of huge importance to agriculture and the environment. Much of the historical work carried out has been within the visible wavelengths of light," said researcher Gary Foster, a professor at the University of Bristol in England.

"However, we know insects can see polarized light regions, and this research does in fact show that plant virus infection can affect the percentage of polarization of light reflected from leaves -- meaning bugs such as greenfly have the potential to 'see' which plants are infected," Foster noted.

"This is an important breakthrough as plant pathogens can play a large part in reducing crop yields, so understanding how viruses are spread means we're better placed to try and tackle the problem," Foster said.

--IANS

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