February 2002. American Samoa asked about the rearing of Aspidiotus destructor.
The white peach scale (Pseudaulacaspis pentagona), pest of passionfruit in Samoa, was reared on potatoes and pumpkin. For P. pentagona potatoes were chosen as host because of their size, which makes them easier to handle and store. Bark pieces with gravid female scales were taken, and these were pinned on the potato/pumpkin skin. Upon hatching, the first instars ('crawlers') would then move to the pumpkin/potato and settle there. Little else needed to be done. Pranish Prasad (formerly of SPC, Fiji, now with MAF New Zealand), found that pumpkin was a better host for A. destructor, since it lasted longer than potatoes. The pumpkins/potatoes should be kept in closed (sealed) boxes with adequate ventilation. There's no need to keep them in an airconditioned room: this would slow down the life cycle, and may even cause dehydration of the host and the scales.
A. destructor can be reared using the techniques described above. A colony was established and maintained in Fiji for several generations as host for coccinellids for biological control programs. The colony was easy to maintain and further generations can be accomplished by brushing the scales onto new pumpkins or by placing them beneath infested ones. The females can be carefully picked up and placed on the pumpkins, or the piece of bark or leaf infested with females can be pinned onto the pumpkin. It is important to screen the colonies to avoid Aphytis (Hymenoptera) parasitoid. Also, mites and fungus can be a problem in
establishing the colony.
It was found that pumpkins were better than potatoes (imported potatoes in Fiji could have had traces of insecticides), and the size of pumkins accomodated more scales, which was an important contributing factor. Also, the potatoes did not last long.