You are so very welcome!* There are no ways to treat viruses as they are caused by insects as they feed.* From this site:
"Prevention and Treatment: There are no chemicals available to kill viruses. Chemical control of the insects that spread the viruses may minimize the disease. This control method is difficult, because infection occurs immediately after an insect feeds, and insects migrate freely between plants. A good control strategy is to maintain healthy and vigorous plants, plant recommended varieties and monitor your garden for any unusual symptoms as they occur. Keep the area clear of weeds that can harbor insects. Choosing separate areas for early and late plantings may help to reduce virus severity in the late plantings."
There is more then one type of Watermelon Mosaic Virus (WMV) but I'm thinking you have WMV-2 listed here.*
"Watermelon mosaic virus 2 (WMV-2) is the second most important cucurbit virus in New York. This virus can infect and produce symptoms on all commercially grown cucurbits. This aphid-transmitted virus causes milder symptoms on the foliage of most infected plants like squash (fig. 4), and growers have seen a lessening of foliar symptoms following fertilization. Fruit distortion and color breaking are still a problem on varieties like yellow straight-neck squash (fig. 5). Use of varieties such as 'Multipik' (fig. 6) can prolong the harvest period because the fruit are marketable in spite of foliar symptoms. The host range for WMV-2 is not limited to cucurbits, thus opening the possible overwintering of this virus in several leguminous species such as clover. Mixed infections of cucurbits with CMV and WMV-2 are common by the end of the season.
Watermelon mosaic virus 1 ( W M V- 1 ) is aphid transmitted, and infection is limited to cucurbits. Although more common in the southern and western regions of the United States, this virus has been recovered in New York several times since it first occurred in epidemic proportions in 1969. This virus is capable of infecting all commercial cucurbit crops. The foliage of affected plants shows strong mosaic, distortion, and deep leaf serration (fig. 7). Fruits are also malformed with knobby overgrowth (fig. 8)."
If that is so you might want to try growing them.* If not, replace with a variety that is resistant.
If you see aphids in the garden you can spray with insecticidal soap.* You can even make your own.
There are several beneficial insects that feed on aphids.* Ladybugs aka Lady beetles and their larvae are good predators.* It would be good to familiarize yourself with what the beneficials look like and plant flowers that attract them.* At this first site start here and then click on each insect at the top of the page.* You'll be amazed at the look of some of these 'good guys and gals' and their larvae.
Two catagories here with some interesting beetles.
More good guys.
How to attract the good guys.
Companion planting might be helpful for you as well since some plants repel the bad bugs.
When weeding, the best way to make sure you are removing a weed and not a valuable plant is to pull on it. If it comes out of the ground easily, it is a valuable plant.