I have been using insecticidal soap for many years and though it has worked in the past, it seems like the beetles just come back in a day. Is this not working anymore? What other organic remedy can you suggest? Cucumber beetles seem to be pretty tough.
You are right; cucumber beetles are tough. Their outer insect skin is thick and rigid making normal sprays virtually useless against this tough armor. Though INSECTICIDAL SOAP has long been used on them, there are other and newer products which work much better these days on this garden pest.
Currently we have two organic gardening sprays which work well. The MULTI PURPOSE INSECT KILLER will be fine if you are only concerned about spraying for nuisance insects. It will handle most anything and you will find it seems to last a week or more when used on cucumber beetles. If you also have mites or fungus in the garden, use the THREE in ONE CONCENTRATE. This product uses several actives which work on many insects as well as common vegetable garden fungus disease. By using the Three in One, you can take care of several concerns with just one spray.