International Produce Training

Watermelons- Ring Spot Virus

A few of you may have encountered some strange circles affecting the rinds of watermelons.  The circles may vary in size and the area affected, but they still usually materially affect the appearance.

This defect is caused by a virus, named the papaya ring spot virus.  These images show the classic symptoms of the virus;  the typical circular patterns.  The virus causes many problems with watermelons grown in Florida, affecting the plants. leaves and the fruit itself.  The virus is transmitted by aphids, as they feed on an infected plant and move to healthy plants.

If you do encounter this defect, rest assured the defect will not progress.  The circular patterns will not become more in number, nor will they spread to perfectly good watermelons.  The USDA does not have any specific scoring guidelines, so you would use judgement to determine if the defect materially affects (damage) or seriously detracts from the appearance (serious damage) of the melon.  If you come across watermelons pictured above, they would be scored as serious damage.  The US Grade Standards for the US No. 1 Grade allow for 10% defects including 5% serious damage.

6 Comments on “Watermelons- Ring Spot Virus”

online universities Says:

Wonderful website. Plenty of useful info here. I am sending it
to some buddies ans also sharing in delicious. And certainly, thanks on your sweat!

Mary Says:

Are these safe to eat or avoid them

Peg Hughes Says:

does this affect whether you can eat it or not?

tyawman Says:

The internal quality is usually not affected, only the rind.

Paula Smith Says:

I have a watermelon with rings on the inside not the outside. Are these also caused by the virus?

tyawman Says:

Paula, good question. When you see circular rings inside a watermelon you are probably seeing the defect second growth. It won’t be harmful if you eat it, but the flavor may be a bit off, maybe not as sweet as you’d like.

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