Nice project! Do you have controlled lighting? If so, the moths are dark blobs on a lighter background? Then maybe this module could work:
If you need several simultaneous bob detection ranges, try http://jevois.org/moddoc/ArUcoBlob/modinfo.html
make sure you use JeVois inventor to easily adjust the double sliders for the HSV ranges.
Otherwise, please upload pictures of your trap somewhere and then link to them here. Maybe a more heavy-duty approach like TensorFlowEasy will be required.