SEMIOCHEMICALS FROM THREE SPECIES OF PITYOPHTHORUS (COLEOPTERA: SCOLYTIDAE): IDENTIFICATION AND FIELD RESPONSE

AbstractAnalyses of pentane extracts of frass, whole beetles, and volatiles trapped on Porapak-Q from Pityophthorus Eichhoff spp. fed on Pinus radiata D. Don demonstrated that (E)-pityol [2-(1-hydroxy-1-methylethyl)-5-methyltetrahydrofuran] was produced by male Pityophthorus carmeli Swaine, female Pityophthorus nitidulus (Mannerheim), and female Pityophthorus setosus Blackman. (E)-(−)-Conophthorin) [(5S,7S)-(−)-7-methyl-1,6-dioxaspiro[4.5]decane] was produced by male P. carmeli and male P. nitidulus. Only the (2R,5S)-(+) stereoisomer of (E)-pityol was produced by male P. carmeli and female P. setosus. In field bioassays in central coastal California, P. setosus was attracted to (E)-(+)-pityol, whereas P. carmeli responded only to a combination of (E)-(−)-conophthorin and (E)-(+)-pityol. Male P. setosus and female P. carmeli responded to these treatments with larger numbers than opposite-sex conspecifics. (E)-(−)-Conophthorin alone did not attract species of Pityophthorus but significantly reduced catches of P. setosus to (E)-(+)-pityol. Lasconotus pertenuis Casey (Coleoptera: Colydiidae) and Ips mexicanus (Hopkins) (Coleoptera: Scolytidae) were attracted to a combination of (E)-(−)-conophthorin and (E)-(+)-pityol, and showed a trend for attraction to all (E)-(−)-conophthorin-containing treatments. (E)-(−)-Pityol was neither attractive nor interruptive for any taxon. (E)-(+)-Pityol is shown to be an aggregation pheromone component for P. carmeli and P. setosus. (E)-(−)-Conophthorin functions as a pheromone component for P. carmeli and may also function as a synomone that decreases competition of P. carmeli and P. nitidulus with P. setosus and as a kairomone for L. pertenuis. These semiochemicals have been useful in studying relationships among twig insects and the pathogen Fusarium circinatum (Nirenberg and O’Donnell), causal agent of pitch canker disease in P. radiata.

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Potential for Outcrossing in an Apparently Asexual Population of Fusarium circinatum, the Causal Agent of Pitch Canker Disease

Mycologia ◽

10.2307/3761476 ◽

2000 ◽

Vol 92 (6) ◽

pp. 1085 ◽

Cited By ~ 15

Author(s):

Karen Wikler ◽

Thomas R. Gordon ◽

Sharon L. Clark ◽

Michael J. Wingfield ◽

Henriette Britz

Keyword(s):

Causal Agent ◽

Pitch Canker ◽

Fusarium Circinatum ◽

Asexual Population ◽

Canker Disease

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Screening of Maritime pine (Pinus pinaster) for resistance to Fusarium circinatum, the causal agent of Pitch Canker disease

Forestry An International Journal of Forest Research ◽

10.1093/forestry/cpr055 ◽

2011 ◽

Vol 85 (2) ◽

pp. 185-192 ◽

Cited By ~ 26

Author(s):

M. Vivas ◽

R. Zas ◽

A. Solla

Keyword(s):

Pinus Pinaster ◽

Causal Agent ◽

Maritime Pine ◽

Pitch Canker ◽

Fusarium Circinatum ◽

Canker Disease

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Potential for outcrossing in an apparently asexual population ofFusarium circinatum, the causal agent of pitch canker disease

Mycologia ◽

10.1080/00275514.2000.12061256 ◽

2000 ◽

Vol 92 (6) ◽

pp. 1085-1090 ◽

Cited By ~ 2

Author(s):

Karen Wikler ◽

Thomas R. Gordon ◽

Sharon L. Clark ◽

Michael J. Wingfield ◽

Henriette Britz

Keyword(s):

Causal Agent ◽

Pitch Canker ◽

Asexual Population ◽

Canker Disease

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Outbreak of Pitch Canker Caused by Fusarium circinatum on Pinus spp. in Northern Spain

Plant Disease ◽

10.1094/pd-89-1015a ◽

2005 ◽

Vol 89 (9) ◽

pp. 1015-1015 ◽

Cited By ~ 74

Author(s):

E. Landeras ◽

P. García ◽

Y. Fernández ◽

M. Braña ◽

O. Fernández-Alonso ◽

...

Keyword(s):

Intergenic Spacer ◽

Morphological Identification ◽

Pitch Canker ◽

Fusarium Circinatum ◽

Northern Spain ◽

Centraalbureau Voor ◽

Canker Disease ◽

Intergenic Spacer Region ◽

Appl Environ ◽

Pinus Spp

During the winter of 2003-2004, dieback symptoms were observed on Pinus radiata and P. pinaster in pine nurseries in Asturias (northern Spain). Small groups of affected seedlings appeared randomly distributed throughout the nurseries. The seedlings died rapidly, showing basal needle dieback, stem lesions, resin exudations, and wilting. Isolations from infected material onto potato dextrose agar (PDA) supplemented with 0.5 mg/ml of streptomycin sulfate and Komada's medium consistently yielded Fusarium sp. cultures. The isolates were transferred to PDA and Spezieller Nährstoffarmer agar and incubated at 25°C for 10 days with a 12-h photoperiod. The cultures were identified as Fusarium circinatum Nirenberg & O'Donnell (= Fusarium subglutinans Wollenweb. & Reinking), causal agent of pitch canker disease, on basis of the presence of polyphialides and characteristic sterile, coiled, hyphae (2). To further confirm their identity, a polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) based on histone H3 gene sequences (4) and a test based on the F. circinatum-specific primers, CIRC1A-CIRC4A, which amplifies a 360-bp DNA fragment of the intergenic spacer region of the nuclear ribosomal operon (3), were used. Results obtained with both techniques confirmed the morphological identification of the cultures. A representative culture has been placed in the Centraalbureau voor Schimmelcultures (CBS 117843). The pathogen was isolated only from seedlings of P. radiata and P. pinaster. Other species such as P. nigra, P. sylvestris, and Pseudotsuga menziesii, which were also grown in these nurseries, did not show symptoms. Pathogenicity was confirmed by inoculating 6- to 9-month-old P. radiata and P. pinaster seedlings. Small strips of bark (10 × 1 mm) were cut from the stems and similar sized pieces of PDA colonized by F. circinatum were placed in contact with the open wounds and covered with parafilm. Basal needle dieback was observed 10 days after inoculation that resulted in wilting of the seedlings. F. circinatum was reisolated from the affected stems fulfilling Koch's postulates. Later in the year, symptoms of pitch canker were also observed on 20-year-old P. radiata in one forest plantation in Cantabria (northern Spain). Infected branches and shoots of the trees exudated abundant resin, resulting in resinous cankers. The needles, distal to branch tip infections, wilt, fade to yellow then red, and fall from the tree. Affected trees showed noticeable crown dieback. The isolations from the cankers also yielded F. circinatum cultures that were identified as described above. Although a nonrefereed report appeared in 1998 (1), to our knowledge, this is the first report of F. circinatum on P. radiata and P. pinaster in Spain and in Europe. References: (1) L. D. Dwinell et al. Int. Congr. Plant Pathol. 7th. 3:9, 1998. (2) H. I. Nirenberg and K. O'Donnell. Mycologia 90:434, 1998. (3) W. Schweigkofler et al. Appl. Environ. Microbiol. 70:3512, 2004. (4) E. T. Steenkamp et al. Appl. Environ. Microbiol. 65:3401, 1999.

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