Q: I’ve seen these nodules on my cantaloupe and melon roots plus other plants I’ve pulled out of my raised beds. Is my garden infested with nematodes? My crop yield on the melons seems quite low.
A: Yes, unfortunately you have root knot nematodes.
They are VERY hard to control. There are no chemicals available for nematode control but you can minimize damage by adding amendments to make your soil a nice sandy loam. This does two things: it makes the plants healthy and strong and it encourages populations of competing harmless nematodes. You might read that marigolds help control nematodes but this is only true if you plant the flowers in a solid block in the garden for a year…and the suppression is only effective for a year afterwards. Some gardeners swear by spraying their plants with aspirin water (I’d try one 250 mg. aspirin per gallon of water). This induces a plant to start an auto-defense system that may help fight nematodes.