I don't know what the likelyhood is, but if you are worried about it, roll the cover up and dunk it in a bucket of bleach water. That should take care of any pest/disease problems.

What did you do with the row cover once you took it off your aphid problem before? How was it stored?

Every year we take our row cover out of the high tunnel, shake it off and then bunch them up and put in large covered trash cans. I have never seen a problem with them overwintering in the row cover.

There are Aphid resistant crops? I would like to know about this.

Jay

Spring, you raise an interesting question and I don't have an answer but I've been just rolling up and tying various row covers, storing in a shed as a "Bundle" and reusing for years without incident. I dip pots and plastic netting in a bleach solution but I would be concerned about weakening the fabric (polypropylene) if it were dipped, even if it was a feasable option. If you just spread the fabric on an open area and allow it to dry for a few days my feeling is that any remaining eggs would hatch and aphids would move to a food source. I would be more concerned about fungal and bacterial diseases overwintering on used fabric but those concerns are still minimal.

I will state that I don't reuse the black plastic that I cover the entire greenhouse soil with. I noticed recently when I removed the plastic that there were unknown egg masses at many of the small openings (2"x3"- made by planting spade) next to tomato stems. This year I used a pruner to cut tomato stems at ground level rather than pulling up the plants by their roots. Since often a few cherry tomatoes and some leaves may remain at those openings I usually make a final pass over the uncovered soil to hand pick any unwanted residue into a bucket for distant composting. I didn't notice insect problems throughout this year but I am concerned about all of those egg masses. I was thinking about spreading lime early on the surface and not cultivating it in until I'm ready to plant again.

Since many insects are repelled or killed by lime you might want to dust powdered limestone over your row cover prior to rolling it up. I have no experience with that and you may not want to put up with the lime dust.

If some aphids overwintered on the row cover it wouldn't make them hit your crop. They infest and multiply when the crop gets hot and bothered whether the row cover is fresh or not. The trick is to take the row cover off before the crop gets warm and too much green growth. There are always an aphid or two around in the garden. Still I would possibly kill them off with bleach or something anyway.

Your post didn't mention if you were an organic grower and if you do use the row cover to protect from insect damage the last thing you want is an infestation under a covered crop. Minnie is right in that weeds like lambsquarter are often vectors for aphids and as soon as conditions are right the population explodes. You may want to focus on other management practices to control aphid issues.