Agdia, a plant diagnostics company based in Elkhart in the United States, has launched a field-deployable rapid molecular test kit for Cucurbit chlorotic yellows virus (CCYV), a disease of melon, cucumber and related crops, Global Agriculture reported. Growers who prefer a laboratory can also send samples to Agdia's testing service, whose cucurbit pathogen screen now includes CCYV.
CCYV belongs to the Crinivirus group. It was first reported in Japan in 2004, infecting melon, and has since been found in many Asian countries, the Middle East, several European countries, Sudan and the United States. It is spread by Bemisia tabaci, the silverleaf or sweetpotato whitefly, and several weed species can carry it between seasons.
Cucumber, melon, watermelon, squash and pumpkin can all suffer. Infected plants show yellowing between the leaf veins, pale spots and mottling, and give lower yields of poorer fruit, including lower sugar content in melons.
The difficulty for growers is that these symptoms look almost the same as those of other viruses, such as Cucurbit aphid-borne yellows virus and Cucurbit yellow stunting disorder virus, and of plain nutrient deficiency; at some stages CCYV can even be mistaken for downy mildew. Each of those problems calls for a different response, so the company says confirming the cause is critical before choosing how to manage the virus and the whitefly that carries it.
Agdia says it ran extensive validation studies to show the molecular assay is fit for purpose. The kit is designed to be paired with the company's AmpliFire Pro isothermal fluorometer, a portable reader that it says is coming soon.
For growers of gourds, melons and cucumbers under whitefly pressure, the point of an on-site test is to know which of these problems they face before deciding whether to control the vector, correct a nutrient shortfall or treat a fungus.
Photo: Stephen Ausmus / Wikimedia Commons (public domain)
Source: Global Agriculture
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