This book provides an illustrated guide to the identification and management of fungi, insects, and abiotic conditions that cause problems in Northwest bareroot conifer nurseries. A key to nursery pests offers initial guidance in identification. Separate chapters address individual pests with details on recognition, damage cycle, and management practices to...
Cones of Douglas-fir and ponderosa pine with extensive mold on external portions of scales were sampled for presence of fungi potentially pathogenic to conifer seedlings in nurseries. The major colonizers of cone scales and external seedcoats for both conifer species were Trichoderma spp. Penicillium spp. were also very common. The...
Tests were conducted at the USDA Forest Service Nursery, Coeur d'Alene, Idaho to evaluate effectiveness of spring fumigation with dazomet to improve survival and performance of Douglas-fir and western white pine transplants. Spring fumigation greatly reduced populations of potentially pathogenic Fusarium and Pythium spp. Disease levels of container (plug+1) and...
Tests were conducted to evaluate efficacy of dry heat (82.2°C for 10, 20, and 60 minutes) to reduce colonization by selected fungi within styroblock containers and residual seedling roots left in containers after seedling extraction. Dry heat alone was generally ineffective in significantly reducing fungal colonization. However, simply wetting container...
Soil in Field 2 at the USDA Forest Service Nursery, Coeur d'Alene, Idaho was assayed six times over a 2-year fallow period for potentially pathogenic Fusarium and Pythium spp. following incorporation of a corn cover/green manure crop. Populations of potentially disease-antagonistic Trichoderma spp. were also assayed. Soil populations of Fusarium...
Thirty-three isolates of Fusarium acuminatum obtained from inland Pacific Northwest forest nurseries were tested for their pathogenicity on young Douglas-fir germinants under controlled laboratory conditions. Tested isolates were from forest nursery soil, roots of healthy-appearing and diseased conifer seedlings, Styrofoam and hard plastic containers, conifer seeds, 411 and adult fungus...
Forty-seven isolates of Fusarium solani obtained from the roots of diseased and healthy conifer seedlings and forest nursery soil were tested for pathogenicity on young Douglas-fir germinants under controlled laboratory conditions. Isolate virulence varied widely; a few were highly virulent whereas many were classified as non-pathogenic. Isolates from the roots...
Investigations were conducted from 1998-
2000 at the Potlatch Corporation's
Cherrylane Seed Orchard near Lewiston,
Idaho to evaluate presence and extent of
potentially pathogenic fungi on roots of
diseased stock and within the soil in current
and proposed plantation sites. The most
common group of pathogens encountered
was Fusarium spp.;...
Fungal pathogens tend to accumulate within styroblock containers, which are reused to produce successive crops of container-grown seedlings. Most nurseries treat reused containers by immersing them in hot water for varying time periods. The efficacy of radio frequency waves (RFs) to reduce levels of selected groups of fungi within styroblock...
Preplant soil treatments were implemented to determine effects on populations of potentiallypathogenic Fusarium and potentially disease-suppressive Trichoderma spp. as well as root colonization by these and other selected fungi on healthy-appearing, bare root 2-0 western white pine seedlings at the USDA Forest Service Nursery, Coeur d'Alene, Idaho. Soil treatments included...
A preliminary evaluation of the biological control formulation of Trichoderma harzianum marketed as BioTrek® was conducted on bareroot Douglasfir and western white pine seedlings at the USDA Forest Service Nursery, Coeur d'Alene, Idaho. The biocontrol material was applied topically on seed shortly after sowing and comparisons made between treated and...
Healthy-appearing 1-0 ponderosa and lodgepole pine seedlings were assayed for root infection and colonization by potentially-pathogenic fungi following pre-sowing soil treatments which included methyl bromide/chloropicrin (MBC) fumigation, fallowing with or/without periodic cultivation, and amending soil with mushroom composts or undecomposed sawdust. Levels of root colonization by Fusarium spp. on both...
Whitebark pine is an important reforestation species in the northern Rocky Mountains for enhancement of wildlife habitat. Production of container-grown whitebark pine seedlings at the USDA Forest Service Nursery in Coeur d'Alene, Idaho has been increasing the past several years. Diseases continue to be an important limiting factor in seedling...
Three stands along Benton Creek within the Priest River Experimental Forest, Idaho, were surveyed for diseases using previously established timber inventory plots and sample trees. These surveys provided information to aid in formation of silvicultural prescriptions by CEFES (Continuing Education in Forest Ecology and Silviculture) students. Diseases were quantified at...
Treating styroblock containers in hot water (68°C) with a very dilute bleach and detergent solution effectively reduced populations of Fusarium and Cylindrocarpon spp., two potential root pathogens of containerized conifer seedlings. However, the treatment did not significantly reduce levels of Phoma (another potential pathogen) nor saprophytic Penicillium and Alternaria spp....
Investigations of containerized conifer seedling root diseases at the Champion Timberlands Nursery revealed that Fusarium oxysporum was most commonly isolated from seed, seedling roots, and styroblock containers. Amount of seed infection varied widely among the seedlots tested, but was usually below 5 percent. Runningwater rinses did not reduce amounts of...
An evaluation of the efficacy of steam treatment on reducing levels of Fusarium, Cylindrocarpon, and
Trichoderma within styroblock containers was conducted at the Plum Creek Nursery in Pablo, Montana. Although levels, of both Fusarium and Cylindrocarpon were significantly reduced by cleaning, relatively high populations of both these fungi persisted after...
Three hundred fifty Leach pine cells used to grow containerized conifer seedlings at the USDA Forest Service Nursery in Coeur d'Alene, Idaho, were sampled for Fusarium and Trichoderma colonization. Cells were either sampled prior to or after cleaning. Cleaning reduced Fusarium colonization from 86 percent of the cells to about...
A total of 45 nondiseased containerized ponderosa pine seedlings from 10 seedlots were sampled at three different times during the growing season for root infection by Fusarium and Trichoderma at the USDA Forest Service Nursery in Coeur d'Alene, Idaho. More than 90 percent of the seedlings had roots infected with...
Investigations of containerized western white pine, western larch, and Douglas-fir seedlings at the Western Forest Systems Nursery in Lewiston, Idaho, revealed that many seedlings were colonized with Fusarium oxysporum although they lacked severe disease symptoms. White pine seedlings were also infected with Pythium spp., probably as a result of sowing...
Investigations were conducted to understand the epidemiology of Fusarium on containerized Douglas-fir seedlings. Types and importance of Fusarium inoculum sources, relationships between seedling infection and symptom production, amounts and types of diseases that occurred throughout typical growth cycles, and the importance of secondary pathogen spread were investigated. Levels of Fusarium...
Benomyl and chlorothalonil were tested on 2-0 bareroot ponderosa pine seedlings as a means to reduce impact of Diplodia tip blight at the Fantasy Farms Nursery, Peck, Idaho. Infection levels were not adequate to assess effectiveness of the fungicides. However, techniques were developed which can be used to assess efficacy...
Causes of mortality of containerized western larch seedlings at the Champion Timberlands Nursery, Plains, Montana, were investigated. Seedlings were rated for disease severity based on extent of foliar decline symptoms and fungal isolations made from their roots. Isolations were also made from selected larch seed. Consistent associations between root colonization...
Mortality of western white pine transplants used to assess resistance to blister rust at the USDA Forest Service Nursery in Coeur d'Alene, Idaho was likely due to extensive root infection by Pythiva app. Severity of foliar symptom production was significantly correlated with extent of root system colonization by these fungi....
Eighteen isolates of Fusarium comprising four species (F. oxysporum, E. avenaceum, E. acuminatum, and F. sambucinum) isolated from diseased conifer seedlings from nurseries were tested for pathogenicity on Douglas-fir germlings. Three of the most pathogenic F. oxysporum isolates on Douglas-fir germlings were also tested on ponderosa pine germlings and older...
Investigations were conducted to determine importance of Fusarium as a pathogen on Douglas-fir seed and containerized seedlings at the Plum Creek Nursery during 1985. Fusarium oxvsnorum was occasionally isolated from necrotic lesions on young germinants that lacked foliar symptoms. Low levels of F. oxvsnorum were detected on three of four...
Containerized western larch, Douglas-fir, grand fir, subalpine fir, and ponderosa pine seedlings which displayed disease symptoms were sampled for presence of Fusarium spp. Seedlings from 33 seedlots within the Northern Region were sampled. Major types of diseases included post-emergence damping-off, root disease (late damping-off), and cotyledon blight. Fusarium oxysporum was...
Isolates of Botrytis cinerea from containerized conifer seedlings from two
nurseries in the Northern Rocky Mountains were exposed to the
dicarboximide fungicides vinclozolin and iprodione and the chlorinated
nitroaniline fungicide dicloran to evaluate occurrence and characteristics
of resistant strains. The isolates were grown on test media prepared by
incorporating the...
Isolates of Fusarium oxysporum, F. acuminatum, and F. sambucinum obtained from peat-vermiculite soil mixes were tested for pathogenicity on ponderosa pine, lodgepole pine, western larch, and blue spruce containerized seedlings and on germination of Scots pine and blue spruce seed. Ponderosa pine seedling were the least susceptible to killing by...
Root disease of 2-0 western white pine seedlings occurred at the Coeur d'Alene Nursery in 1982 within seedbeds fumigated with methyl bromide and chloropicrin. Although losses were not substantial, there were several groups of dead seedlings within affected seedbeds. Fusarium oxysporum was most often isolated from diseased roots. Other Fusarium...
A survey for incidence and distribution of root diseases was conducted on the Kootenai National Forest using timber inventory subcompartments as primary sample units. Root diseases were located within 23 of 75 sampled subcompartments. At least 1.1 percent of the commercial forest lands within the Forest are infested with root...
Root diseases were evaluated on the Reuben's Reserve, Nez Perce Indian Reservation, Idaho. Nineteen trees adjacent to two suspected root disease centers were pushed with a D-6 tractor to expose their root systems. Extent of root necrosis and decay was determined and related to level of crown thinning, chlorosis, and...
Five fungicides were evaluated to control Botrytis blight of containerized western larch seedlings at the Champion Timberlands Nursery, Plains, MT. Fungicides were applied at biweekly intervals before and after seedling inoculation with Botrytis. Vinclozolin (Ornalin®) caused severe phytotoxicity to seedlings, resulting in enhanced mortality and premature needle loss. Captan and...
Needle tip dieback of 2-0 ponderosa pine seedlings at the Coeur d'Alene Nursery was investigated. Organisms associated with dieback symptoms were identified and infected trees were transplanted to determine disease effects on survival. The major fungus colonizing necrotic needles was Lophodermium nitens, a close associate of L. pinastri. The fungus...
Fungi associated with cankers of Russian-olive seedlings at the Montana State Nursery, Missoula, were investigated. Phomopsis elaeagni was most often isolated from and fruiting on cankers. Other associated fungi were Phoma herbarum, P. eupyrena, P. chrysanthemicola, P. exigua, Alternaria alternate, Epicoccum nigrum, and Fusarium moniliforme. Because of its common occurrence...
Six fungicides were evaluated to control Botrytis blight of western 41 larch in seedbeds at the Coeur d'Alene Nursery. Fungicides were applied at biweekly intervals during the spring of 1982; test seedlings were inoculated with spores of B. cinerea twice during the evaluation period. Seedling mortality and height were recorded...
Tests were conducted to determine levels of tolerance of 10 Botrytis cinerea isolates from the Flathead Indian Reservation greenhouse (Ronan, MT) to six fungicides. In vitro growth and conidial germination on fungicide-amended potato dextrose agar were used as criteria for assessing tolerance. All tested isolates were tolerant to benomyl and...
Two methods attempting to stop marginal spread of a root disease center in Douglas-fir were evaluated within the Flathead Indian Reservation, Montana. The first method was to cut all living trees within a 1-chain strip outside the edge of the infestation. The second method was to uproot all trees for...
An impact survey to determine extent and distribution of root disease centers was completed for the Nezperce National Forest, Idaho, in 1980. Lowlevel
color infrared photography was used to delineate root disease centers
within National Forest inventory subcompartments. Suspected root disease
centers were ground checked to determine associated fungi and...
A root disease evaluation was completed for the Ducharme logging unit near the southeast corner of Flathead Lake. Extensive root disease was found on Douglas-fir throughout the unit. The major pathogen on the site was Armillaria meilea. Black stain (Verticicladiella sp.) was isolated from one tree which was also infected...
Five seedlots of Colorado blue spruce and three seedlots of Black Hills spruce were sampled for Fusarium contamination. All seedlots contained some seed and/or debris with Fusarium. Levels of contamination were greatly reduced by treating seed with running water rinses for 48 hours or with chemical sterilants such as sodium...