Predominant nitidulid species (Coleoptera: Nitidulidae) associated with spring oak wilt mats in Minnesota

2001 ◽  
Vol 31 (4) ◽  
pp. 635-643 ◽  
Author(s):  
Kory R Cease ◽  
Jennifer Juzwik

Nitidulids are primary vectors of the oak wilt pathogen, Ceratocystis fagacearum (Bretz) Hunt, in the north-central United States. Species of adult nitidulids associated with different ages of oak wilt fungus mats on red oaks (Quercus rubra L. and Quercus ellipsoidalis E.J. Hill) during spring in east-central Minnesota were determined. The exoskeletal surfaces of representative specimens were assayed for the presence and abundance of the pathogen. Six species comprised 94% of 2542 adults, representing at least 12 species, collected between 1994 and 1996. Of these six species, Colopterus truncatus Randall and Epuraea corticina Erichson were the most abundant ones on immature mats (94% of 154 nitidulids). They were also more abundant than the other species on mature mats (77% of 868 nitidulids). Carpophilus sayi Parsons was the most common species (28% of 1134 nitidulids) on aging mats, while Carpophilus sayi and three Glischrochilus species (Glischrochilus sanguinolentus (Oliv.), Glischrochilus fasciatus (Oliv.), and Glischrochilus quadrisignatus Say) were predominant on declining mats (80% of 214 nitidulids). Multiple numbers of individuals of each species were commonly found on the mats. The smaller bodied species, C. truncatus and E. corticina, had the lowest numbers of fungal propagules on their bodies, while the highest incidence and numbers of viable propagules were found for the three largest bodied species (Glischrochilus spp.). These results are important to elucidating the principal nitidulid species involved in successful transmission of the pathogen in Minnesota.

Plant Disease ◽  
2005 ◽  
Vol 89 (10) ◽  
pp. 1067-1076 ◽  
Author(s):  
Angie K. Ambourn ◽  
Jennifer Juzwik ◽  
Roger D. Moon

Sap beetles (Nitidulidae) are considered important overland vectors of the oak wilt pathogen, Ceratocystis fagacearum, in the north central United States. Colopterus truncatus and Carpophilus sayi are thought to be the principal sap beetle vectors in Minnesota. Field studies using windoriented funnel traps baited with aggregation pheromones of the insects were conducted during 2 years in east central Minnesota. The studies compared temporal flight dynamics of Colopterus truncatus and Carpophilus sayi from April through October, measured the proportion of dispersing adults of each species carrying viable pathogen propagules, and estimated the populations of contaminated dispersing beetles in oak (Quercus spp.) stands with and without oak wilt. Abundance of Colopterus truncatus peaked in either April or May, but the pathogen was most frequently isolated (20 to 45%) from beetles obtained from oak wilt sites from July through September. However, the highest contaminated insect population (CIP) generally occurred during April and May. Abundance of Carpophilus sayi peaked in October of both years, but the pathogen was most commonly isolated from beetles collected during May and June. The CIP was highest in June. The infective insect potential, as indexed by CIP, was greatest for both species in the spring and was greater for Colopterus truncatus than for Carpophilus sayi.


2014 ◽  
Vol 15 (3) ◽  
pp. 92-96 ◽  
Author(s):  
Guirong Zhang ◽  
Carl A. Bradley

Historically, frogeye leaf spot (FLS, caused by Cercospora sojina) of soybean has been observed more frequently in the southern United States than the north-central United States. However, in recent years, FLS field observations have increased in the north-central United States. To better understand the survival rate of C. sojina in Illinois, a field study was conducted at three locations: Monmouth (west-central Illinois), Urbana (east-central Illinois), and Dixon Springs (southeastern Illinois). At each location, soybean leaves affected by FLS were placed at depths of 0, 10, and 20 cm and retrieved at different durations up to 24 months. To determine the viability of C. sojina in the collected leaves, a greenhouse bioassay was used. Survival of C. sojina declined equally with time at all three locations through 19 months. After 24 months, C. sojina from leaves that had been placed at Monmouth and Urbana were no longer viable, whereas leaves that had been placed at Dixon Springs produced viable inoculum. Depth of leaf placement had no effect on survival of C. sojina at any of the locations. These results suggest that planting a nonhost crop for two years in central Illinois will reduce levels of C. sojina inoculum to a negligible amount; however, soybean farmers in southern Illinois may need a longer rotation for FLS management. Accepted 10 May 2014. Published 23 July 2014.


1980 ◽  
Vol 10 (3) ◽  
pp. 257-263 ◽  
Author(s):  
K. D. Widin ◽  
A. L. Schipper Jr.

Development of the aecial and uredial stages of Melampsoramedusae leaf rust of poplar in relation to the phenology of its hosts (Populus spp. and Larix spp.) was monitored from March until October during two consecutive growing seasons in central Iowa, east central Minnesota, and north central Wisconsin. Both years, in Wisconsin, larch needles flushed in early May and poplar leaves flushed in mid-May to late May. Aeciospores of M. medusae were found on spore traps only at the Wisconsin site (within the natural range of larch) from May 19 until the end of June in 1975 and 1976. Uredospores were present in the north central United States from mid-June through late September during both years. Temperatures between 15° and 20 °C and periods of precipitation favored uredospore production. Poplar leaf rust was found successively later at more southerly locations.


Plant Disease ◽  
2009 ◽  
Vol 93 (4) ◽  
pp. 428-428 ◽  
Author(s):  
S. Jensen-Tracy ◽  
S. Kenaley ◽  
G. Hudler ◽  
T. Harrington ◽  
C. Logue

Ceratocystis fagacearum (T.W. Bretz) J. Hunt is considered to be the most destructive vascular pathogen of oaks (Fagaceae: Quercus spp.) in the eastern, north-central, and south-central United States. (1,2,4). All red oak species (subgenus Quercus: section Lobatae) are highly susceptible to C. fagacearum, and infected trees typically die within 3 months of first symptom expression. However, members of the white oak group (subgenus Quercus: section Quercus) are moderately to highly resistant to C. fagacearum and rarely die from oak wilt (1,3). In early August of 2008, we received branch samples taken from wilting red oaks (Q. rubra L.) growing in a residential neighborhood in Scotia, NY (Schenectady County). The endoconidial state of the oak wilt fungus, Thielaviopsis quercina (B.W. Henry) A.E. Paulin, T.C. Harr. & McNew, was consistently isolated from the xylem in the branches. The cultures were identified based on hyphal and conidial morphology on acidified potato dextrose agar (aPDA) as well as sequences of the internal transcribed spacer (ITS) (GenBank Accession No. FJ347031) and large subunit (LSU) (GenBank Accession No. FJ347030) regions of nuclear ribosomal DNA (rDNA). The nucleotide identities for the ITS and LSU sequences were a precise match, 99 and 100%, to rDNA sequences (GenBank Accession Nos. AF043598 and AF222483, respectively) of other isolates of C. fagacearum. According to the homeowners at the site, 12 red oaks have died during the last 3 years, and each tree died within one growing season after oak wilt-like symptoms were noted. In a brief survey of nearby properties in late August of 2008, we found 12 additional trees that were either expressing crown symptoms of oak wilt (e.g., premature leaf casting, bronzing of leaf margins, and water-soaked leaves) or were standing dead and within close proximity (5 to 10 m) to symptomatic trees. Branch samples from four of the symptomatic trees revealed limited (spotted) or no vascular discoloration; however, C. fagacearum was isolated from each suspect tree on aPDA. Remnants of gray mycelial mats and associated pressure cushions were observed beneath the bark of one standing dead oak. The sweet fruit-like odor characteristic of the oak wilt fungus was immediately evident once the bark overlying the mats was removed. Prior to this discovery, the Susquehanna River in north-central Pennsylvania was considered to be the northeastern limit for oak wilt occurrence in the United States (2,4). To our knowledge, this is the first report of the fungus from New York and expands the known range of C. fagacearum to the northeast by at least 300 km, supporting the hypothesis that the range of this fungus continues to expand via animal vectors and/or human activities (2). An isolate of C. fagacearum from New York has been deposited at the Centraalbureau voor Schimmelcultures (CBS 123913). References: (1) D. N. Appel. Ann. Rev. Phytopathol. 33:103, 1995. (2) J. Juzwik et al. Ann. Rev. Phytopathol. 46:13, 2008. (3) W. L. MacDonald et al. European oaks-susceptible to oak wilt? Page 131 in: Shade Tree Wilt Diseases. C. L. Ash, ed. The American Phytopathological Society, St. Paul, MN, 2001. (4) USDA Forest Service. Oak Wilt Distribution. Northeast Area, State and Private Forestry, St. Paul, MN. Online publication, 2005.


PLoS ONE ◽  
2015 ◽  
Vol 10 (9) ◽  
pp. e0139188 ◽  
Author(s):  
Laura Aldrich-Wolfe ◽  
Steven Travers ◽  
Berlin D. Nelson

1995 ◽  
Vol 52 (2) ◽  
pp. 416-424 ◽  
Author(s):  
James W. LaBaugh

Algal chlorophyll a is commonly used as a surrogate for algal biomass. Data from three lakes in western Nebraska, five wetlands in north-central North Dakota, and two lakes in north-central Minnesota represented a range in algal biovolume of over four orders of magnitude and a range in chlorophyll a from less than 1 to 380 mg∙m−3. Analysis of these data revealed that there was a linear relation, log10 algal biovolume = 5.99 + 0.09 chlorophyll a (r2 = 0.72), for cases in which median values of chlorophyll a for open-water periods were less than 20 mg∙m−3. There was no linear relation in cases in which median chlorophyll a concentrations were larger than 20 mg∙m−3 for open-water periods, an occurrence found only in shallow prairies lakes and wetlands for years in which light penetration was the least.


1987 ◽  
Vol 1 (4) ◽  
pp. 341-349 ◽  
Author(s):  
R. Gordon Harvey ◽  
J. H. Dekker ◽  
Richard S. Fawcett ◽  
Fred W. Roeth ◽  
Robert G. Wilson

Research conducted since 1979 in the north central United States and southern Canada demonstrated that after repeated annual applications of the same thiocarbamate herbicide to the same field, control of some difficult-to-control weed species was reduced. Laboratory studies of herbicide degradation in soils from these fields indicated that these performance failures were due to more rapid or “enhanced” biodegradation of the thiocarbamate herbicides after repeated use with a shorter period during which effective herbicide levels remained in the soils. Weeds such as wild proso millet [Panicum miliaceumL. spp.ruderale(Kitagawa) Tzevelev. #3PANMI] and shattercane [Sorghum bicolor(L.) Moench. # SORVU] which germinate over long time periods were most likely to escape these herbicides after repeated use. Adding dietholate (O,O-diethylO-phenyl phosphorothioate) to EPTC (S-ethyl dipropyl carbamothioate) reduced problems caused by enhanced EPTC biodegradation in soils treated previously with EPTC alone but not in soils previously treated with EPTC plus dietholate. While previous use of other thiocarbamate herbicides frequently enhanced biodegradation of EPTC or butylate [S-ethyl bis(2-methylpropyl)carbamothioate], previous use of other classes of herbicides or the insecticide carbofuran (2,3 -dihydro-2,2 -dimethyl-7-benzofuranyl methylcarbamate) did not. Enhanced biodegradation of herbicides other than the thiocarbamates was not observed.


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