scholarly journals Seasonal Dispersal of the Oak Wilt Fungus by Colopterus truncatus and Carpophilus sayi in Minnesota

Plant Disease ◽  
2005 ◽  
Vol 89 (10) ◽  
pp. 1067-1076 ◽  
Author(s):  
Angie K. Ambourn ◽  
Jennifer Juzwik ◽  
Roger D. Moon
Keyword(s):  
Field Studies ◽  
Aggregation Pheromones ◽  
Oak Wilt ◽  
North Central ◽  
East Central ◽  
Ceratocystis Fagacearum ◽  
The North ◽  
Sap Beetles ◽  
Central United States ◽  
Quercus Spp

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.

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
Keyword(s):  
Common Species ◽  
Oak Wilt ◽  
North Central ◽  
East Central ◽  
Ceratocystis Fagacearum ◽  
The North ◽  
Red Oaks ◽  
Fungal Propagules ◽  
Central United States ◽  
Quercus Ellipsoidalis

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.

scholarly journals Survival of Cercospora sojina on Soybean Leaf Debris in Illinois

2014 ◽  
Vol 15 (3) ◽  
pp. 92-96 ◽  
Author(s):  
Guirong Zhang ◽  
Carl A. Bradley
Keyword(s):  
United States ◽  
Southern Illinois ◽  
Cercospora Sojina ◽  
North Central ◽  
East Central ◽  
The North ◽  
Central United States ◽  
Soybean Leaf ◽  
Soybean Leaves ◽  
Central Illinois

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.

Epidemiology of Melampsoramedusae leaf rust of poplars in the north central United States

1980 ◽  
Vol 10 (3) ◽  
pp. 257-263 ◽  
Author(s):  
K. D. Widin ◽  
A. L. Schipper Jr.
Keyword(s):  
United States ◽  
Leaf Rust ◽  
North Central ◽  
East Central ◽  
Growing Seasons ◽  
The North ◽  
Central United States ◽  
Natural Range ◽  
Poplar Leaf ◽  
Populus Spp

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.

scholarly journals Colonization of Oak Wilt Fungal Mats by Ophiostoma piceae During Spring in Minnesota

Plant Disease ◽  
1997 ◽  
Vol 81 (4) ◽  
pp. 410-414 ◽  
Author(s):  
Jennifer Juzwik ◽  
Jason M. Meyer
Keyword(s):  
Wound Surface ◽  
Oak Wilt ◽  
East Central ◽  
Ceratocystis Fagacearum ◽  
Ophiostoma Piceae ◽  
Colony Forming Units ◽  
Different Ages ◽  
Quercus Spp

The colonization of Ceratocystis fagacearum fungal mats of different ages by Ophiostoma piceae on Quercus spp. was determined in three east-central Minnesota locations during the spring of 1995. The extent of the mat area colonized by O. piceae generally increased with mat age. Subsamples per mat yielding the fungus for the three locations averaged 11 to 27% for immature mats, 65 to 72% for mature mats, and 66 to 96% for aging and declining mats. On a mat-incidence basis, frequencies of O. piceae isolation from at least one subsample of an immature mat ranged from 30 to 53% compared with more than 90% for all other mat ages in the three locations. The average number of colony-forming units of O. piceae per square centimeter ranged from 1 × 103 to 1.2 × 106 and increased with mat age. The extent of C. fagacearum recovery from each mat was lower for aging plus declining mats (P < 0.03) compared with other ages in two locations. On a mat-incidence basis, frequency of C. fagacearum recovery from at least one subsample of a mat averaged 99% for all ages of mats in all locations. The interaction between O. piceae and C. fagacearum on mats, nitidulids, and the oak wound surface is discussed.

scholarly journals Genetic Variation of Sclerotinia sclerotiorum from Multiple Crops in the North Central United States

PLoS ONE ◽  
2015 ◽  
Vol 10 (9) ◽  
pp. e0139188 ◽  
Author(s):  
Laura Aldrich-Wolfe ◽  
Steven Travers ◽  
Berlin D. Nelson
Keyword(s):  
United States ◽  
Genetic Variation ◽  
Sclerotinia Sclerotiorum ◽  
North Central ◽  
The North ◽  
Central United States

Relation of algal biovolume to chlorophyll a in selected lakes and wetlands in the north-central United States

1995 ◽  
Vol 52 (2) ◽  
pp. 416-424 ◽  
Author(s):  
James W. LaBaugh
Keyword(s):  
United States ◽  
North Dakota ◽  
Chlorophyll A ◽  
Linear Relation ◽  
Algal Biomass ◽  
Open Water ◽  
Light Penetration ◽  
North Central ◽  
The North ◽  
Central United States

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.

Enhanced Biodegradation of Herbicides in Soil and Effects on Weed Control

1987 ◽  
Vol 1 (4) ◽  
pp. 341-349 ◽  
Author(s):  
R. Gordon Harvey ◽  
J. H. Dekker ◽  
Richard S. Fawcett ◽  
Fred W. Roeth ◽  
Robert G. Wilson
Keyword(s):  
Weed Species ◽  
North Central ◽  
Herbicide Degradation ◽  
Proso Millet ◽  
The North ◽  
Central United States ◽  
Enhanced Biodegradation ◽  
Long Time ◽  
Previously Treated ◽  
Repeated Use

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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