Colonization of cut branches of five coniferous hosts of the pitch canker fungus by Pityophthorus spp. (Coleoptera: Scolytidae) in central, coastal California

2005 ◽  
Vol 137 (3) ◽  
pp. 337-349 ◽  
Author(s):  
Nadir Erbilgin ◽  
Andrew J. Storer ◽  
David L. Wood ◽  
Thomas R. Gordon
Keyword(s):  
Ponderosa Pine ◽  
Field Experiments ◽  
Selective Medium ◽  
Douglas Fir ◽  
Pitch Canker ◽  
Fusarium Circinatum ◽  
Monterey Pine ◽  
Host Trees ◽  
Low Incidence ◽  
Emerging Insects

AbstractPitch canker of pines (Pinus spp.) and Douglas-fir (Pseudotsuga menziesii (Mirbel) Franco) (Pinaceae) is caused by the fungus Fusarium circinatum Nirenberg et O'Donnell. In California, infections by F. circinatum occur largely through wounds caused by insects. Field experiments were initiated to determine whether the colonization activities of twig beetles, Pityophthorus spp. (Coleoptera: Scolytidae), could explain the incidence of pitch canker on Monterey pine (P. radiata D. Don), Bishop pine (P. muricata D. Don), ponderosa pine (P. ponderosa var. ponderosa Dougl.), knobcone pine (P. attenuata Lemm.), and Douglas-fir. Asymptomatic branches were cut from each of four pairs of tree species (Monterey–Bishop, Monterey–ponderosa, Monterey–knobcone, Monterey–Douglas-fir) at four sites and attached to the lower canopy of both heterospecific and conspecific host trees (total of four combinations per pair). After 10 weeks, branches were collected and placed in rearing tubes in the laboratory. Emerging insects were identified and placed on a Fusarium-selective medium. Monterey, Bishop, and ponderosa pines were more heavily infested by Pityophthorus spp. than Douglas-fir and knobcone pine. Furthermore, more Pityophthorus beetles emerged from Monterey pine branches placed in Monterey pine canopies than from Monterey pine branches placed in Bishop or ponderosa pine canopies, indicating that reduced emergence (colonization) was caused by the hetero specific host. Relatively fewer insects emerged from sites containing either Monterey and knobcone pines or Monterey pine and Douglas-fir. Fusarium circinatum was not isolated from emerging Pityophthorus spp. Susceptibility of the five host species, based on mean lesion lengths resulting from mechanical inoculations, varied significantly. The longest lesions were on Monterey pine and the shortest were on ponderosa pine and Douglas-fir. The low incidence of pitch canker on Douglas-fir and ponderosa pine in nature compared with that on Monterey, Bishop, and knobcone pines may be explained by the low colonization by twig beetles and the greater resistance of Douglas-fir and ponderosa pine to this disease, compared with the other three hosts.

scholarly journals Detection and Quantification of Airborne Conidia of Fusarium circinatum, the Causal Agent of Pine Pitch Canker, from Two California Sites by Using a Real-Time PCR Approach Combined with a Simple Spore Trapping Method

2004 ◽  
Vol 70 (6) ◽  
pp. 3512-3520 ◽  
Author(s):  
Wolfgang Schweigkofler ◽  
Kerry O'Donnell ◽  
Matteo Garbelotto
Keyword(s):  
Real Time ◽  
Filter Paper ◽  
Real Time Pcr ◽  
Fungal Spores ◽  
Seasonal Fluctuation ◽  
Selective Medium ◽  
Pitch Canker ◽  
Fusarium Circinatum ◽  
Intergenic Spacer Region ◽  
Monterey Pine

ABSTRACT Pinus radiata (Monterey pine), a tree native to coastal California and Mexico, is widely planted worldwide for timber production. A major threat to Monterey pine plantations is the fungal disease pine pitch canker, caused by Fusarium circinatum (Hypocreales). We present a novel trapping approach using filter paper in combination with a rapid molecular method to detect the presence of inoculum in the air. The assay is also useful for diagnosing the presence of the pathogen on plants. The test is based on the F. circinatum specific primer pair CIRC1A-CIRC4A, which amplifies a 360-bp DNA fragment in the intergenic spacer region of the nuclear ribosomal operon. Real-time PCR was used to calculate the number of fungal spores present in each reaction mixture by comparing the threshold cycle (Ct) of unknown spore samples to the Ct values of standards with known amounts of F. circinatum spores. The filter paper method allows prolonged and more sensitive spore sampling in the field compared to traditional traps using petri dishes filled with selective medium. A field test at two sites in coastal California infested with pine pitch canker was carried out during the summer and fall of 2002. Spore counts were in the range of ca. 1 � 103 to ca. 7 � 105/m2, with the highest spore counts in the fall, suggesting a seasonal fluctuation.

Incidence of the pitch canker pathogen and associated insects in intact and chipped Monterey pine branches

2002 ◽  
Vol 134 (1) ◽  
pp. 47-58 ◽  
Author(s):  
William R. McNee ◽  
David L. Wood ◽  
Andrew J. Storer ◽  
Thomas R. Gordon
Keyword(s):  
Temporal Variation ◽  
Pinus Radiata ◽  
Pitch Canker ◽  
Fusarium Circinatum ◽  
Coastal Site ◽  
Monterey Pine ◽  
Canker Pathogen ◽  
The Mean ◽  
Emerging Insects

AbstractIn a 2-year study of Monterey pine, Pinus radiata D. Don (Pinaceae), infected with pitch canker, caused by Fusarium circinatum Nirenberg and O'Donnell, less than 2% of symptomatic branches with green foliage were colonized by twig beetles in the genus Pityophthorus Eichhoff (Coleoptera: Scolytidae), whereas approximately 50% of branches with yellow and red foliage were colonized. More Pityophthorus spp. emerged from yellow branches (mean ± SE = 12.1 ± 1.7 per 30 cm) than from red branches (6.9 ± 0.9) at an inland study site (Oakland) but, at a coastal site (Pebble Beach), the means were not significantly different (4.3 ± 0.6 and 3.8 ± 0.7). The mean phoresy rate of all emerging insects was higher at Pebble Beach (17.7 ± 0.6%) than at Oakland (5.3 ± 0.2%). At both sites, there was considerable temporal variation in the proportion of branches colonized by twig beetles, mean numbers of emerging twig beetles, and phoresy rates of emerging insects. Chipping branches reduced the emergence of Pityophthorus spp. and associates by approximately 95%, compared with emergence from intact branches. The pathogen was isolated from 1-year-old branches and chips in up to 68% of samples, but was only recovered from 3-year-old branches in 1 of 46 sampled. It is recommended that recent branch cuttings and chips originating from symptomatic trees not be transported to areas that are believed to be free of the disease.

scholarly journals First Report of the Pitch Canker Fungus (Fusarium circinatum) in the Sierra Nevada of California

Plant Disease ◽  
2004 ◽  
Vol 88 (7) ◽  
pp. 772-772 ◽  
Author(s):  
D. R. Vogler ◽  
T. R. Gordon ◽  
B. J. Aegerter ◽  
S. C. Kirkpatrick ◽  
G. A. Lunak ◽  
...  
Keyword(s):  
New Zealand ◽  
Sierra Nevada ◽  
Douglas Fir ◽  
Wash Water ◽  
Pathogenicity Test ◽  
Pitch Canker ◽  
Fusarium Circinatum ◽  
Single Spore ◽  
Monterey Pine ◽  
Morphological Criteria

The pitch canker fungus, Fusarium circinatum (teleomorph Gibberella circinata), was isolated from a branch originating from rootstock of a Douglas-fir (Pseudotsuga menziesii) graft in a breeding orchard at 1,000m elevation in El Dorado County, California. We visited the orchard after the New Zealand Ministry of Agriculture and Forestry reported in November 2003 that a Douglas-fir scion (branch cutting) shipped from there in January—and subsequently grafted and held in a quarantine facility near Christchurch—was infected with the pitch canker fungus. We took samples throughout the orchard of any branches that appeared unhealthy. In addition, asymptomatic branches from the tree alleged to be the source of the New Zealand infestation were collected to assay for propagules of F. circinatum. Wash water from these branches was negative for the pathogen. Likewise, F. circinatum was not recovered from water washings of 20 branches collected randomly throughout the orchard. Fifteen branch samples collected from symptomatic Douglas-fir grafts were cultured on water agar and only one yielded a colony with an appearance consistent with F. circinatum. A single spore subculture of this isolate was confirmed as F. circinatum on the basis of colony morphology and the structure of the microconidiophores (1). The virulence of this isolate was evaluated by inoculating susceptible 2-year-old Monterey pine (Pinus radiata) seedlings with a toothpick to wound the main stem and insert potato dextrose agar colonized by the fungus. Twenty-four days later, pitching and yellow needles were evident at the site of inoculation, and removal of the bark revealed resin-soaked and discolored tissue. Concurrent with the pathogenicity test described above, a culture of the putative F. circinatum isolated in New Zealand was inoculated into Monterey pines with an identical outcome. The fungus was reisolated from lesions from both sets of inoculations and confirmed as F. circinatum based on morphological criteria. Isolates GL285 and GL286 are available from T. R. Gordon upon request. Prior to its discovery in the Sierra Nevada, pitch canker in California was known only from counties on or near the coast. Our report indicates the pathogen can survive and infect trees 110 km east of the previous most-inland site of infestation. It remains to be seen how extensively pitch canker will develop in the Sierra Nevada. Douglas-fir is only moderately susceptible to F. circinatum, which has not been observed to cause significant damage to this species. On the other hand, low-elevation Sierra Nevada pines including P. sabiniana, P. coulteri, and P. ponderosa are substantially more susceptible than are Douglas-fir in greenhouse tests (2). References: (1) T. R. Gordon et al. Mycol. Res. 100:850, 1996. (2) T. R. Gordon et al. Plant Dis. 85:1128, 2001.

Effects of pitch canker pathogen on gallery excavation and oviposition by Ips paraconfusus (Coleoptera: Scolytidae)

2002 ◽  
Vol 134 (4) ◽  
pp. 519-528 ◽  
Author(s):  
Andrew J. Storer ◽  
David L. Wood ◽  
Thomas R. Gordon
Keyword(s):  
Pinus Radiata ◽  
Ips Paraconfusus ◽  
Multiple Infections ◽  
Pitch Canker ◽  
Fusarium Circinatum ◽  
Monterey Pine ◽  
Naturally Occurring ◽  
Canker Pathogen ◽  
Negative Effect ◽  
The Mean

AbstractIps paraconfusus Lanier is a vector of the pitch canker fungus, Fusarium circinatum Nirenberg and O’Donnell, in California. Multiple infections of Monterey pine, Pinus radiata D. Don. (Pinaceae), branches and main stems appear to predispose trees to infestation by I. paraconfusus. The effect of cankers produced in response to F. circinatum on oviposition and gallery construction was investigated. Introduction of beetles into artificially induced or naturally occurring cankers was less likely to result in oviposition and resulted in shorter galleries than introductions into logs without cankers. Of all adults that produced eggs, the mean number of eggs per adult was no different in logs with cankers than in canker-free logs; however, the distance across the grain from the introduction point to the first egg was greater for adults introduced into cankers than for adults introduced away from cankers. These results indicate that the pitch canker pathogen has a negative effect on I. paraconfusus, as cankers produced in response to the pathogen are unsuitable for exploitation by the insect.

scholarly journals Susceptibility of Douglas fir (Pseudotsuga menziesii) to pitch canker, caused by Gibberella circinata (anamorph = Fusarium circinatum)

2006 ◽  
Vol 55 (2) ◽  
pp. 231-237 ◽  
Author(s):  
T. R. Gordon ◽  
S. C. Kirkpatrick ◽  
B. J. Aegerter ◽  
D. L. Wood ◽  
A. J. Storer
Keyword(s):  
Pseudotsuga Menziesii ◽  
Douglas Fir ◽  
Pitch Canker ◽  
Fusarium Circinatum ◽  
Gibberella Circinata

Twig beetles, Pityophthorus spp. (Coleoptera: Scolytidae), as vectors of the pitch canker pathogen in California

2004 ◽  
Vol 136 (5) ◽  
pp. 685-693 ◽  
Author(s):  
Andrew J. Storer ◽  
David L. Wood ◽  
Thomas R. Gordon
Keyword(s):  
Pinus Radiata ◽  
Fungal Spores ◽  
Pitch Canker ◽  
Fusarium Circinatum ◽  
Monterey Pine ◽  
Canker Pathogen ◽  
Disease Free

AbstractTwig beetles in the genus Pityophthorus Eichhoff are known to be associated with the pitch canker pathogen, Fusarium circinatum, in California. Phoresy of the pathogen on these species has been reported to occur when insects emerge from diseased branches and when they infest disease-free, cut branch tips. To demonstrate that twig beetles can vector the pathogen, studies of phoresy and transmission were conducted in a native Monterey pine, Pinus radiata D. Don (Pinaceae), forest. Phoresy was confirmed for both Pityophthorus setosus Blackman and Pityophthorus carmeli Swaine, and P. setosus was shown to vector the pitch canker pathogen when contaminated with fungal spores and caged onto Monterey pine branches. When attractive baits were used to increase visitation to Monterey pines by P. setosus, baited trees were more likely to develop pitch canker than unbaited trees even though the beetles did not tunnel into the host to develop egg galleries. Therefore, twig beetles are competent as vectors of the pitch canker pathogen, and their vectoring activity, though requiring a wound, does not require that they establish egg galleries in the host.

The role of Pityophthorus spp. as vectors of pitch canker affecting Pinus radiata

2007 ◽  
Vol 139 (6) ◽  
pp. 864-871 ◽  
Author(s):  
Joyce M. Sakamoto ◽  
Thomas R. Gordon ◽  
Andrew J. Storer ◽  
David L. Wood
Keyword(s):  
Relative Humidity ◽  
Pinus Radiata ◽  
Low Temperatures ◽  
Native Species ◽  
Field Experiments ◽  
Infection Frequency ◽  
Pitch Canker ◽  
Monterey Pine ◽  
Canker Pathogen

AbstractThe fungus Fusarium circinatum Nirenberg and O’Donnell (Hypocreaceae) causes pitch canker, a disease affecting pines worldwide. In California, many native insect species have been implicated in transmission of F. circinatum. This study showed that two twig beetle species, Pityophthorus setosus Blackman and Pityophthorus carmeli Swaine (Coleoptera: Curculionidae: Corthylini), can make wounds on healthy Monterey pine (Pinus radiata D. Don (Pinaceae)) branches that are suitable for infection by the pitch canker pathogen. Because these two species are not known to engage in maturation feeding and the observed wounds were not associated with tunneling, we hypothesize that the wounds reflect “exploratory tasting” to assess the suitability of the substrate for colonization. This behavior would help to explain how twig beetles can serve as wounding agents on healthy host branches, which are not amenable to colonization by these insects. We tested two specific hypotheses: (1) two native species of Pityophthorus can create wounds on F. circinatum-contaminated trees that are sufficient for development of disease; and (2) the efficiency with which F. circinatum infects beetle wounds is affected by relative humidity. Under growth-chamber conditions, both Pityophthorus species indulged in exploratory behavior that caused wounds suitable for development of pitch canker. Field experiments did not confirm a significant effect of beetle activity on infection frequency, perhaps because of an overall low infection rate due to low temperatures. Experiments conducted under controlled conditions documented a significant effect of relative humidity on the success rate of twig beetle-initiated infections.

scholarly journals Projecting Monterey Pine (Pinus radiata) Populations over Time in the Presence of Various Representations of Pitch Canker Disease, Caused by Fusarium circinatum

Forests ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 437
Author(s):  
Gregory J. Reynolds ◽  
Thomas R. Gordon ◽  
Neil McRoberts
Keyword(s):  
Pinus Radiata ◽  
Transition Probabilities ◽  
Transition Probability ◽  
Initial Population ◽  
Native Forest ◽  
Pitch Canker ◽  
Fusarium Circinatum ◽  
Projection Model ◽  
Size Classes ◽  
Monterey Pine

Monterey pine (Pinus radiata D. Don) is native to California and widely planted in Mediterranean climates around the world. Pitch canker, a disease caused by Fusarium circinatum Nirenberg and O’Donnell, is a serious threat to P. radiata in native forests and in plantations. Because of its economic importance worldwide, conservation of P. radiata native populations is a high priority. We developed a demographic matrix projection model to simulate dynamics of naturally occurring P. radiata populations in California in the presence of the disease. Tree demography data for the model were collected from seven sites in a native forest on the Monterey Peninsula. Height and stem diameter were recorded for all trees, which were divided into five size classes based on these data. Transition probabilities were calculated for each size class; cone production, seed release, and seed transition probability were estimated using an iterative search process. In the model, pitch canker influences state-specific fecundity and survival probabilities. Five different approaches to include these effects were compared. Populations were projected over 50 decades from three specified initial population sizes. Elasticity analysis indicated that facilitating survival of all size classes is vital to maintaining the structure of the forest.

scholarly journals Variation in Rates of Spore Deposition of Fusarium circinatum, the Causal Agent of Pine Pitch Canker, Over a 12-Month-Period at Two Locations in Northern California

2008 ◽  
Vol 98 (1) ◽  
pp. 137-143 ◽  
Author(s):  
M. Garbelotto ◽  
T. Smith ◽  
W. Schweigkofler
Keyword(s):  
Causal Agent ◽  
Pitch Canker ◽  
Northern California ◽  
Fusarium Circinatum ◽  
Monterey Pine ◽  
Forest Pathogen ◽  
Aerial Dispersal ◽  
Trapping Method ◽  
Spore Trapping ◽  
Spore Deposition

Patterns of spore deposition by Fusarium circinatum, the causal agent of pine pitch canker (PPC) of Monterey pine (Pinus radiata) and other conifers, were studied between May 2003 and April 2004 at two sites in Northern California using a novel spore trapping method combined with a real-time polymerase chain reaction (PCR) approach. At each study site, two plots were sampled by placing spore traps at 100 m intervals along transects 600 m in length. The air was sampled continuously by exchanging the spore traps every 2 weeks. The spore deposition rate (DR), ranged from 0 to 1.3 × 105 spores m–2. Spores were detected throughout the year, with higher trapping frequencies (TF) during the rainy season (November to April), than during the dry season (May to October). The detection of spores on traps at distances larger than 200 m from any Monterey pine, suggests at least midrange aerial dispersal. Finally, different inoculum loads were associated with trees displaying different levels of disease symptoms, suggesting infectiousness of the pathogen varies as the disease progresses. This study represents one of the first documenting continuous inoculum pressure values over an entire year for a forest pathogen, and provides important epidemiological information that will be invaluable in the development of disease progression models.

scholarly journals Douglas Fir and Ponderosa Pine Seed Dormancy as Regulated by Grassland Seedbed Conditions

2004 ◽  
Vol 57 (6) ◽  
pp. 661 ◽  
Author(s):  
Yuguang Bai ◽  
Don Thompson ◽  
Klaas Broersma
Keyword(s):  
Seed Dormancy ◽  
Ponderosa Pine ◽  
Douglas Fir
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