Biochemical assays for identifying seeds of lodgepole pine and other conifers fed on by Leptoglossus occidentalis Heidemann (Hemiptera : Coreidae)

Radiography is a valuable tool for assessing quality of conifer seeds, but it cannot differentiate between aborted seeds and seeds that have been empt ied by western conifer seed bug (Leptoglossus occidentalis Heidemann) feedi ng. We tested three biochemical marker-based assays that were developed to identify L. occidentalis damage to seeds of Douglas-fir, Pseudostuga menzie sii (Mirb.) Franco, for their use in lodgepole pine, Pinus contorta var. la tifolia Engelmann. The three assays included measurement of storage protein reserve depletion, immunodetection of fragments of insoluble (crystalloid) storage proteins, and immunodetection of L. occidentalis salivary proteins . Aborted seeds contained significantly less soluble and insoluble protein than seeds that were fed on by L. occidentalis. Polyclonal antibodies raise d against 11S globulin crystalloid proteins or L. occidentalis salivary gla nd extracts only immunoreacted with proteins in seeds exposed to L. occiden talis feeding. In a single-blind test, antibody raised against salivary-gla nd extracts correctly distinguished between undamaged full seeds, unfilled aborted seeds, and seeds fed on by L. occidentalis. Immunodetection of L. o ccidentalis salivary proteins was also performed on seeds of Abies amabilis Dougl. ex J. Forbes, Tsuga heterophylla (Raf.) Sarg., Picea sitchensis Bon g (Carr.), Pinus ponderosa Lawson, and Pinus monticola Dougl. ex D. Don. Fo r all species, immunoreactive polypeptides were only detected in seeds fed on by L. occidentalis. These biochemical marker-based techniques could help researchers and seed orchard managers estimate seed losses caused by L. oc cidentalis in commercial seed orchards and natural forest stands.