Biological control of grapevine scales

The distribution of soft scales that infest grapevines in mainland Australia, their natural enemies, and factors affecting the populations of scales in commercial vineyards were investigated during 2004-2008. Grapevine scale, Parthenolecanium persicae, and frosted scale, Parthenolecanium near pruinosum, were the most common scales, but sometimes occurred in mixed infestations with each other and/or other soft scale species. Soft brown scale (Coccus hesperidum), long soft scale (Coccus longulus), nigra scale (Parasaissetia nigra), and a Saissetia sp. were also found on grapevines. Both grapevine scale and frosted scale had one generation per year, reproducing in early spring. Metaphycus maculipennis was an effective solitary parasite of juvenile grapevine scale, and gregarious parasite of mature grapevine scale, reducing its reproductive capacity.