Thursday, 15 March 2012
The larvae of two species can be bred from Norway Spruce cones collected at this time of year; Assara terebrella and Cydia strobilella. Cones containing A. terebrella larvae are reported to be stunted and sometimes deformed but those with C. strobilella rarely show any external signs of being occupied so you just need to collect a random selection. Whilst A. terebrella comes to light, people don't often trap conifer plantations so it is under recorded. C. strobilella flies around the top of spruces in afternoon sunshine and is therefore rarely recorded as an adult.
Cones that are collected now should be kept in a container that allows circulation of air (to prevent mould) but you will obviously need to have some sort of netting over the container to prevent any emerging adults from disappearing before you notice them! I give the cones a light spray with water occasionally.