Sorry to hear this! We'd expect this product to kill wasps on contact, so your feedback has been passed along. We'd also appreciate the chance to help further, so when you have a moment, please email us here: https://contact.scjbrands.com/en-us. Or call 1-800-558-5252, weekdays from 8 AM to 6 PM CT. Your reference number is: 019530645A.