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.

ASSOCIATION BETWEEN A NATIVE SPITTLEBUG (HOMOPTERA: CERCOPIDAE) ON MONTEREY PINE AND AN INTRODUCED TREE PATHOGEN WHICH CAUSES PITCH CANKER DISEASE

1998 ◽  
Vol 130 (6) ◽  
pp. 783-792 ◽  
Author(s):  
Andrew J. Storer ◽  
David L. Wood ◽  
Karen R. Wikler ◽  
Thomas R. Gordon
Keyword(s):  
Pinus Radiata ◽  
Spore Suspension ◽  
Field Observations ◽  
Pitch Canker ◽  
Canker Disease ◽  
Feeding Sites ◽  
Monterey Pine ◽  
Canker Pathogen ◽  
Monterey Peninsula

AbstractJuvenile Monterey pines, Pinus radiata D. Don (Pinaceae), in a native stand on the Monterey Peninsula, California, exhibited wilted green shoots in the spring of 1996. The pitch canker fungus, Fusarium subglutinans (Wollenweb. & Reinking) P.E. Nelson, Toussoun & Marasas f.sp. pini, was subsequently isolated from 95% of these shoots. Spittle masses produced by Aphrophora canadensis Walley were observed on the symptomless shoots of many of these trees. The pitch canker fungus was isolated from the feeding sites of this insect on 55% of symptomless shoots, and from shoot sections adjacent to these feeding sites on 29% of the shoots. Shoots with spittlebugs feeding on them in May 1996 were more likely to develop pitch canker disease by September 1996 and March 1997 than shoots without spittlebugs. Shoots with spittle masses in March 1997 were as likely to develop pitch canker disease by May and August 1997 as shoots without spittle masses, but the origin of the infection was most likely where A. canadensis feeding had taken place. In a controlled test, the incidence of pitch canker on shoots of potted Monterey pines was dependent on the presence of a spittlebug and a spore suspension of the pathogen. Thus, both field observations and controlled studies show an association between native A. canadensis and the introduced pitch canker pathogen. The role of A. canadensis in the epidemiology of pitch canker disease remains to be determined.

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.

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.

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.

scholarly journals Monterey pine forest made a remarkable recovery from pitch canker

2020 ◽  
Vol 74 (3) ◽  
pp. 169-173
Author(s):  
Gordon Thomas R. ◽  
Reynolds Gregory J. ◽  
Kirkpatrick Sharon C. ◽  
Storer Andrew J. ◽  
Wood David L. ◽  
...  
Keyword(s):  
Pinus Radiata ◽  
Rapid Progression ◽  
Native Forest ◽  
Pitch Canker ◽  
Santa Cruz ◽  
Monterey Pine ◽  
Native Populations ◽  
Remarkable Recovery ◽  
Monterey Peninsula ◽  
Observation Period

Monterey pine (Pinus radiata) is a species of limited distribution, with three native populations in California. In 1986, a disease known as pitch canker, caused by the fungus Fusarium circinatum, was identified as the cause of extensive mortality in planted Monterey pines in Santa Cruz County. Monitoring studies on the Monterey Peninsula documented rapid progression of the disease in the native forest during the 1990s, with most trees sustaining some level of infection. However, between 1999 and 2013, the severity of pitch canker stabilized, with many previously diseased trees then free of symptoms, and plots monitored between 2011 and 2015 documented a steady decline in the occurrence of new infections. Consequently, whereas pitch canker was once a conspicuous visual blight in the forest, by the end of the observation period, symptomatic trees had become a rarity. The arrested development of pitch canker is suggestive of a reduction in the frequency and duration of fog near the coast, which provides conditions necessary for the pathogen to establish infections.

scholarly journals Limiting Effects of Low Temperature on Growth and Spore Germination in Gibberella circinata, the Cause of Pitch Canker in Pine Species

Plant Disease ◽  
2008 ◽  
Vol 92 (4) ◽  
pp. 542-545 ◽  
Author(s):  
A. R. Inman ◽  
S. C. Kirkpatrick ◽  
T. R. Gordon ◽  
D. V. Shaw
Keyword(s):  
Spore Germination ◽  
Low Temperatures ◽  
Geographic Origin ◽  
Field Trials ◽  
Effect Of Temperature ◽  
Infection Frequency ◽  
Pitch Canker ◽  
Time Required ◽  
Gibberella Circinata ◽  
Pine Species

Pitch canker, caused by Gibberella circinata (anamorph = Fusarium circinatum), causes canopy dieback and mortality in susceptible pine species in many parts of the world. Pitch canker is most problematic in areas with a relatively warm climate, suggesting a possible limitation on disease development imposed by low temperatures. To test this hypothesis, the effect of temperature on radial growth was examined in isolates of G. circinata of diverse geographic origin. All isolates grew most rapidly at 25°C and progressively more slowly at 20, 15, and 10°C. Spore germination occurred most rapidly at 20°C and was slowest at 10°C. To determine if the time required for spore germination might influence the likelihood of infection, the duration of wound susceptibility was examined by inoculating branches of susceptible Monterey pines (Pinus radiata). In each of six field trials, branches were wounded and then inoculated immediately or at 2, 6, or 9 days after wounding. The results indicated that wounds inoculated immediately became infected at a significantly higher rate than those inoculated 2 days later. Thus, if low temperatures extend the time required for germination beyond this period, a reduced infection frequency would be expected. Such a limiting effect of temperature could help to explain the current distribution of pitch canker.

TRANSMISSION OF THE PITCH CANKER FUNGUS, FUSARIUM SUBGLUTINANS F. SP. PINI, TO MONTEREY PINE, PINUS RADIATA, BY CONE- AND TWIG-INFESTING BEETLES

1996 ◽  
Vol 128 (6) ◽  
pp. 981-994 ◽  
Author(s):  
Kelli Hoover ◽  
David L. Wood ◽  
Andrew J. Storer ◽  
Joseph W. Fox ◽  
William E. Bros
Keyword(s):  
Pinus Radiata ◽  
Insect Vectors ◽  
Beetle Species ◽  
Pitch Canker ◽  
Fusarium Subglutinans ◽  
Experimental Conditions ◽  
Canker Disease ◽  
Average Percentage ◽  
Monterey Pine ◽  
Plant Parts

AbstractConophthorus radiatae Hopkins, Ernobius punctulatus Fall, and Pityophthorus spp. infest cones and twigs of Monterey pines (Pinus radiata D. Don) and thus may be important vectors of the pitch canker fungus Fusarium subglutinans f. sp. pini in the central coast of California. Fifteen percent of 1st-year Monterey pine conelets infested with C. radiatae prior to August 1990 developed pitch canker by May 1991. Conophthorus radiatae, E. punctulatus, and Pityophthorus spp. were dissected from some of these conelets and found carrying F. s. pini. Between June 1990 and May 1991, 16% of 695 randomly selected uninfested 1st-year conelets from a total of 329 separate cone whorls were infested by at least one of the above beetle species, and F. s. pini was isolated from 42% of the attacked conelets. Average percentage contamination of beetles per conelet was highest for adults of Pityophthorus spp. (38%), followed by adults of C. radiatae (33%), larvae of E. punctulatus (24%), and larvae of Pityophthorus spp. (5%). There were significant associations between conelets that contained contaminated C. radiatae, Pityophthorus spp., and/or E. punctulatus and conelets with F. s. pini.Under experimental conditions, C. radiatae and E. punctulatus transmitted the fungus to healthy cones. Ernobius punctulatus required an entrance tunnel by C. radiatae to enter and infect the cone. Artificially wounded cones did not develop pitch canker. Intra- and interspecific transmission of F. s. pini was demonstrated among these beetle species. In infested branch tips without cones, interspecific transmission of F. s. pini between E. punctulatus and Pityophthorus spp. was also demonstrated.The roles of C. radiatae and E. punctulatus as vectors of F. s. pini and of Pityophthorus spp. as potential vectors are discussed in relation to the epidemiology of pitch canker disease. The spread of pitch canker to California’s native pines as well as other conifers may be enhanced by interspecific transmission of F. s. pini between E. punctulatus and C. radiatae in cones and between E. punctulatus and Pityophthorus spp. in branch tips. Ernobius punctulatus provides a pathway for the fungus to potential insect vectors that attack several hosts and a variety of plant parts.

scholarly journals Pitch Canker Disease of Pines

2006 ◽  
Vol 96 (6) ◽  
pp. 657-659 ◽  
Author(s):  
T. R. Gordon
Keyword(s):  
United States ◽  
Somatic Mutations ◽  
Pitch Canker ◽  
Vegetative Compatibility Group ◽  
Canker Disease ◽  
Monterey Pine ◽  
Canker Pathogen ◽  
Repeated Infection ◽  
Compatibility Group ◽  
California Population

Pitch canker, caused by Fusarium circinatum, is a disease affecting pines in many locations throughout the world. The pathosystem was originally described in the southeastern (SE) United States and was identified in California in 1986. Limited vegetative compatibility group (VCG) diversity in the California population of F. circinatum, relative to the SE United States, suggests the former is a recently established and clonally propagating population. Although the much greater VCG diversity found in the SE United States is suggestive of out-crossing, molecular markers indicate that many vegetatively incompatible isolates are clonally related. This implies that VCG diversity may derive, at least in part, from somatic mutations rather than sexual reproduction. Pitch canker is damaging to many pine species and one at particular risk is Monterey pine (Pinus radiata), which is widely grown in plantations and is highly susceptible to pitch canker. However, some Monterey pines are resistant to pitch canker and some severely diseased trees have been observed to recover. The absence of new infections on these trees reflects the operation of systemic induced resistance, apparently in response to repeated infection by the pitch canker pathogen.

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.

Sign in / Sign up

Export Citation Format

Share Document