Fusarium circinatum is the causal agent for the disease, pitch canker, in Pinus patula. Commercial forestry incurs large economic losses from the pathogen, primarily as a result of post-planting mortality resulting in increased re-establishment costs. One means of enhancing defense is through pretreatment of seedlings with chemicals or biologically derived compounds that stimulate defense responses; a process collectively known as induced resistance. We compared the efficiency of ten inducers in improving defense against F. circinatum in P. patula seedlings. Chitosan (10mg/ml) was effective in reducing and delaying disease symptoms of pitch canker in seedlings. Under both nursery and greenhouse conditions, chitosan application resulted in reduced lesion lengths in treated plants compared to non-treated plants over a period of six weeks (p<0.05, Kruskal–Wallis). Reverse transcription-quantitative PCR expression analysis revealed that the reduction in lesion size in treated seedlings was accompanied by a four-fold increase in transcript abundance of the phenylalanine ammonia lyase transcript, which encodes an enzyme involved in the first committed step of the phenylpropanoid pathway. We suggest that the application of chitosan as part of an integrated management strategy, be further investigated for an effective approach to induce resistance in P. patula seedlings against F. circinatum

Sirex noctilioFabricius (Hymenoptera, Siricidae) is rare and rarely studied where it is native in Eurasia, but is a widespread pest of pines in the Southern Hemisphere. Here we report on the abundance, basic biology, host use patterns and natural enemies of nativeS. noctilioin Galicia, Spain. Most trees attacked byS. noctiliofailed to produce any adult progeny: >90% of emergences came from <20% of the attacked trees. The highest reproduction was inPinus pinaster, followed byPinus sylvestrisandPinus radiata.The proportions ofS. noctiliorequiring 1, 2 or 3 years for development were 0.72: 0.24: 0.04. Delayed development could be an adaptation to avoid parasitic nematodes, which sterilized 41.5% adults with one year generation time but only 19% of adults with 2 years generation time. Hymenoptera parasitoids accounted for 20% mortality. Sex ratios were male biased at 1: 2.9. Body size and fecundity were highly variable and lower than previously reported from the Southern Hemisphere. On attacked trees, there were 5–20 attacks per standard log (18 dm²), with usually 1–3 drills per attack. Attack densities and drills per attack were higher in trees that subsequently died. The production ofS. noctilioper log was positively related to total attacks, and negatively related to: (1) attack density, (2) incidence of blue stain fromOphiostomafungi and (3) frequency of lesions in plant tissue around points of attack. A preliminary life table for S.noctilioin Galicia estimated effects on potential population growth rate from (in decreasing order of importance) host suitability, unequal sex ratio, parasitic nematodes and Hymenoptera parasitoids.

Deladenus nitobein. sp., a parasite of a woodwasp species,Sirex nitobei, is described based on its typological characters and molecular profiles of part of the small subunit D2-D3 expansion segments of the large subunit and internal transcribed spacer region of the ribosomal RNA gene, as well as part of the mitochondrial cytochrome oxidase subunit I (mtCOI) gene. Adult host woodwasps emerging from dead Japanese red pine logs,Pinus densiflora, collected at Aomori, Japan, were dissected and examined for nematode association. The new species was isolated from the body cavity and reproductive system ofS. nitobeias large parasitic females and small parasitic juveniles. The nematodes were cultured successfully on 1.0% malt extract agar medium, inoculated withSirex-associated fungus,Amylostereumareolatum. The mycophagous adult nematodes were characterised by the relative position of the excretory pore, located at 25 (19-28) and 25 (18-30)μm anterior to the hemizonid in the male and female, respectively, and a broad female tail with a rounded distal end. Typologically, the new species forms a cryptic species complex withD. siricidicolaandD. canii. In addition, the new species andD. siricidicolashare the same host wasp, tree and fungal species in Japan. However, the cryptic species can be separated from each other based on the described morphological and molecular sequence differences in the mtCOI gene.