Greetings I have recently cleaned last years colony trays and washed cocoons. What exactly do you look for when candling the cocoons? Thanks
You're looking for the larvae of parasitic wasps, which will appear as a cluster of small objects inside the cocoon. A mason bee pupa will be a single object with the usual shape of a bee (might look like 3 lumps). Sometimes it is hard to see the difference. You can also gently squeeze the cocoon and feel the difference, as the wasp-infested cocoon will be soft and squishy, while one with a bee will have a firm and lumpy object inside.