Cucumber beetles??

Neem oil hinders an insect's ability to feed and reproduce, it also acts as a repellent. So it will affect beneficial insects.

Beetles breed in the soil, treat the soil treat the beetles. You can spray neem or spinosad on the plant and do a spinosad soil drench but the best bet would be adding DE and crab meal to the soil.

Crab meal will shred the soft bodies of beetle grubs and the DE will scratch up the insects and suck the moisture from their exoskeleton essentially dehydrating them to death.

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The larvae live in the soil as it states there to feed on the roots. Beneficial insects don't feed on the leaves but neem oil repells insects from the leaves.

Neem Oil General Fact Sheet

Neem also inhibits fungal growth (both beneficial and harmful) and repells (beneficial) insects and nematodes in the soil making it a bad soil drench. Spinosad is low toxicity and will kill beneficial soil insects but not microbes or fungus and nematodes and also won't harm the micro fauna living in the soil or feeding on yhe soil fungus making it an excellent soil drench.

Killing the larvae will end the life cycle.

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Oh I absolutely agree on spraying the plant. But the soil needs treatment too or they come back.

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