For the past number of years, many potato researchers in several countries around the world have been focusing on the problem of zebra chip disease of potatoes, and the insect that transmit this disease to spud tubers, the potato tomato psyllid. Zebra chip became a serious problem for many potato growers and processors alike during the past few years in many potato producing countries, including North America, Europe, Australia and New Zealand. Zebra chip is caused by the Liberibacter bacterium and spread by tiny, winged insects called potato psyllids – and it creates bands in tuber flesh that darken during frying. University of Idaho (UI) researchers are studying reflections of various light wavelengths off of zebra chip-infected potatoes, seeking to devise a quicker and more precise method of quantifying disease prevalence.
UI Extension entomologist Arash Rashed and his collaborators have been using a spectrometer — a device that records signatures of reflected light wavelengths — to evaluate infected tubers from other UI zebra chip experiments for comparison with healthy tubers. Xi Liang, a UI cropping systems agronomist, is assisting with spectrometer analysis, and Zhiguo Zhao, a visiting scientist from China, is developing a computer model, based on the data, to predict the progression of zebra chip infection without frying. Rashed said Zhao’s software should also enable the industry to estimate the growth stage in which infections occurred and predict the further development of zebra chip symptoms in storage. Rashed he hopes to have initial results in October to justify a larger grant for his research, and he anticipates working with UI Extension storage specialist Nora Olsen on storage trials, using Zhao’s model.
A new portable diagnostic tool for identifying the devastating zebra chip disease may bring faster and more accurate results to stem its spread, according to New Zealand scientists. Dr Grant Smith is a plant pathologist with the Plant and Food Research institute in New Zealand and has been working on the development of the tool. He said current tests were not accurate enough. Plant and Food Research have been using a genomic approach to develop the new diagnostic tool. According to Dr Smith, the new technology would also be portable and cut waiting times from two-three days to roughly 30 minutes.
The use of fine mesh covers could be the answer to controlling the tomato potato psyllid. Dr Charles Merfield, the head of the BHU Future Farming Centre in New Zealand, who has been researching the use of mesh in potato crops, believes the problem of the psyllid may be solved. The latest research by the farming centre compared an agrichemical regime with three meshes of different hole size: 0.3, 0.4 and 0.7mm. Agrichemicals had a total of 1614 psyllids, while the meshes had four, five and three psyllids.
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