S. Rooney-Latham

California Department of Food and Agriculture | cdfa · Plant Pest Diagnostics Lab

The genus Tubakia is revised on the basis of morphological and phylogenetic data. The phylogenetic affinity of Tubakia to the family Melanconiellaceae (Diaporthales) was recently postulated, but new analyses based on sequences retrieved from material of the type species of Tubakia, T. dryina, support a family of its own, viz. Tubakiaceae fam. nov....

Carica papaya and other species of the genus Carica are hosts of numerous powdery mildews belonging to various genera, including some records that are probably classifiable as accidental infections. Using morphological and phylogenetic analyses, five different Erysiphe species were identified on papaya, viz. Erysiphe caricae, E. caricae-papayae sp....

White leaf smut is a minor foliar disease of sunflower (Helianthus annuus) in the United States. The disease occurs primarily in greenhouse-grown sunflowers in California and causes leaf spot, defoliation, and a reduction in yield and crop value. Historically, many Entyloma specimens with similar morphological characters, but infecting diverse plan...

Abstract: Trunk diseases diminish vineyard longevity and productivity in nearly every raisin, table, and wine grape production region worldwide. Fungi causing these diseases infect primarily through pruning wounds. One way to control these diseases is to protect pruning wounds with fungicide applications, which can be problematic because of the lim...

From December 2004 through May 2009, samples were collected from California nurseries and wild lands to survey for Phytophthora ramorum and comply with federal regulations of nursery stock. Samples were prescreened by an enzyme-linked immunosorbent assay (ELISA) that detects Phytophthora spp. and tested by culture, P. ramorum-specific real-time pol...

Goji berries (Lycium barbarum and L. chinense) have a rich historical significance in traditional Chinese medicine and have gained popularity as a superfood in Western cultures. From 2021 to 2023, powdery mildew was observed on goji plants of both species in community and residential gardens in Yolo County, California (USA). Disease severity varied...

In November 2022 and February 2023, CAL FIRE tree health experts examined four maples (Acer spp.) planted decades earlier in a residential setting in Elk Grove, Sacramento Co., California (USA). Three of the trees were silver maples (Acer saccharinum ) and one was a Norway maple (A. platanoides); both species are exotic to California. The trees wer...

Cornus capitata Wall. ex Roxb. (evergreen dogwood) is a bushy evergreen tree or shrub native to East Asia grown for its showy creamy bracts in late spring followed by attractive red fruit. In Feb 2023, a sample of foliage with leaf spots and tip dieback from C. capitata ‘Mountain Moon’ was submitted from a Humboldt Co. nursery as part of a CDFA ins...

We report observations of Onnia subtriquetra on bishop pine (Pinus muricata) and shore pine (Pinus contorta var. contorta) from north coastal California. Our identification of this fungus is supported by molecular information, morphological characteristics, and and a description of the observed range of the fungus on the West Coast. These observati...

Goji berries, both Lycium barbarum, and L. chinense, are native to Asia and have been highly valued for food and medicinal purposes for more than 2,000 years (Wetters et al. 2018). These species are difficult to distinguish due to the extensive cultivar development of the former and the plasticity of the latter's phenotypes. During the summers (fro...

hree Botryosphaeriaceae species, not previously recorded on coast redwood, were detected from native redwood stands in Humboldt Co., CA during general surveys between 2014 and 2017. Pathogenicity experiments with three of these fungi, Diplodia scrobiculata, Diplodia mutila, and Dothiorella californica, were performed on 2-year-old redwood seedlings...

Golden or giant chinquapin, Chrysolepis chrysophylla (Fagaceae), is a slow growing, evergreen shrub or tree, native to the west coast of the US. In April 2015, several declining chinquapin trees were identified on Bolinas Ridge near Mt. Tamalpais in Marin Co. CA, a Phytophthora ramorum infested region. Branch dieback was observed but no bole or bra...

Spaghetti squash (Cucurbita pepo L. subsp. pepo) is a yellow-skinned squash that forms translucent spaghetti-like strands when cooked. California leads the nation in total squash production, the majority of which is grown in the San Joaquin Valley. In October of 2019, severe fruit rot of C. pepo L. subsp. Pepo (C. pepo) was observed in fruit harves...

Novel species of fungi described in this study include those from various countries as follows: Algeria, Phaeoacremonium adelophialidum from Vitis vinifera. Antarctica, Comoclathris antarctica from soil. Australia, Coniochaeta salicifolia as endophyte from healthy leaves of Geijera salicifolia, Eremothecium peggii in fruit of Citrus australis, Micr...

Brisbane box,Lophostemon confertus (Myrtaceae) is a frost tender evergreen tree planted for its upright form, large ovate leaves and attractive white flowers which bloom in the spring. In June of 2017, the Plant Pest Diagnostics Center lab received a call from an arborist who described Brisbane box street trees dying in central Sausalito, Marin Co....

The genus Arctostaphylos (Ericaceae) includes more than 100 species of evergreen shrubs and small trees, most of which are endemic to California and many considered threatened or endangered (Wahlert et al. 2009). In May and June 2017, foliar and stem samples of two Arctostaphylos species were submitted for disease diagnosis to the CDFA Plant Pest D...

Background: Previous phylogenetic analyses of species within the genus Golovinomyces (Ascomycota, Erysiphales), based on ITS and 28S rDNA sequence data, revealed a co-evolutionary relationship between powdery mildew species and hosts of certain tribes of the plant family Asteraceae. Golovinomyces growing on host plants belonging to the Heliantheae...

Phytophthora tropicalis-like internal transcribed spacer (ITS) sequences were detected with Illumina MiSeq from irrigation water, soil and gravel, and root balls of container-grown Pieris plants at a commercial nursery in Oregon in 2015 to 2018 (Parke et al. 2019; Redekar et al. 2019). A Phytophthora isolate (JP-18-01) matching the species descript...

Powdery mildew of Prunus spp. is a significant disease in most cherry growing regions of Washington, USA. Powdery mildews on Prunus virginiana and Pr. avium were previously assigned to Podosphaera clandestina s. lat. (= Po. oxyacanthae) or Po. prunicola. In this report, we confirm the presence of two distinct Podosphaera species on these hosts. Phy...

Coast redwood (Sequoia sempervirens) is among the most widely planted landscape trees in California (CA) but is in decline outside its natural range due to factors including prolonged drought and plant pathogens. We investigated associations of Botryosphaeriaceae fungi with declining coast redwood trees throughout CA. More than 100 samples were col...

Phytophthora tentaculata was detected for the first time in North America in 2012 in a nursery on sticky monkeyflower plant (Diplacus aurantiacus) and again in 2014 on outplanted native plants. At that time, this species was listed as a federally actionable and reportable pathogen by the USDA. As a result of these detections, California native plan...

Coast redwood is among the most planted landscape trees in California. Outside its natural range, coast redwood is in decline due to factors including climate change and the movement of plant pathogens. We investigated the fungi associated with leaf blight and canker in declining urban stands of coast redwood. Symptomatic leaves, shoots and branch...

Coast redwood is among the most planted landscape trees in California. Outside its natural range, coast redwood is in decline due to factors including climate change and the movement of plant pathogens. We investigated the fungi associated with leaf blight and canker in declining urban stands of coast redwood. Symptomatic leaves, shoots and branch...

Ming Aralia, Polyscias fruticosa (Araliaceae), is a tropical evergreen shrub and dwarf tree native to India. Specimens are usually grown indoors as houseplants but can also be grown outdoors in tropical areas. Between March and September 2013, three Ming Aralia samples with extensive cankers were submitted to the California Department of Food and A...

The potential aerial spread of Phytophthora ramorum, causal agent of Sudden Oak Death and Ramorum blight, from infected plants in a quarantine research nursery at the National Ornamentals Research Site at Dominican University of California (NORS-DUC) to the environment was monitored weekly for five years (2011-2016) using a sentinel system. P. ramo...

Fava bean, Vicia faba L., broad bean, is eaten in many cuisines, and is planted worldwide as a rotation crop for erosion control and soil improvement. In April 2014, fava bean plants were collected from a seed field in Santa Clara County, CA. Clusters of stunted and declining plants were reported before flowering with further decline after seed set...

California, with approximately 90% of the production, is the leading producer of avocado (Persea americana Mill), in the United States, followed by Florida and Hawaii (California Avocado Commission 2016). Diseases on avocado, caused by members of the Botryosphaeriaceae, can result from entry through natural openings, wounds caused by mechanical dam...

Oenothera lindheimeri (= Gaura lindheimeri), gaura, is a perennial shrub native to Texas and Louisiana and grown for its graceful airy form and long blooming period. In November 2013, rust samples from an incoming shipment containing fifty O. lindheimeri plants in 3.8-liter pots were taken from a nursery in Contra Costa County and sent to the CDFA...

In June 2006, a residential apple tree (Malus domestica Borkh. cv. Honeycrisp) was submitted to the California Department of Food and Agriculture’s Plant Pest Diagnostics Center. The bare root tree was planted in January 2006 in a landscape in Santa Clara Co. In the spring, the tree began exhibiting branch cankers and dieback symptoms. The resident...

California is the fifth largest apple-producing state in the United States with approximately 6,150 ha (USDA-NASS 2015). In June 2012, container-grown apple trees (Malus domestica Borkh. cv. Newtown Pippin) from Sonoma Co., CA, were submitted to the California Department of Food and Agriculture’s Plant Pest Diagnostics Laboratory. The county agricu...

Novel species of fungi described in the present study include the following from Malaysia: Castanediella eucalypti from Eucalyptus pellita, Codinaea acacia from Acacia mangium, Emarcea eucalyptigena from Eucalyptus brassiana, Myrtapenidiella eucalyptorum from Eucalyptus pellita, Pilidiella eucalyptigena from Eucalyptus brassiana and Strelitziana ma...

Novel species of fungi described in the present study include the following from Malaysia: Castanediella eucalypti from Eucalyptus pellita, Codinaea acacia from Acacia mangium, Emarcea eucalyptigena from Eucalyptus brassiana, Myrtapenidiella eucalyptorum from Eucalyptus pellita, Pilidiella eucalyptigena from Eucalyptus brassiana and Strelitziana ma...

Novel species of fungi described in the present study include the following from Malaysia: Castanediella eucalypti from Eucalyptus pellita, Codinaea acacia from Acacia mangium, Emarcea eucalyptigena from Eucalyptus brassiana, Myrtapenidiella eucalyptorum from Eucalyptus pellita, Pilidiella eucalyptigena from Eucalyptus brassiana and Strelitziana ma...

Phytophthora tentaculata Kröber & Marwitz (Pythiaceae) has been detected in several native plant nurseries in 4 California counties and in restoration sites on orange sticky monkey flower (Diplacus aurantiacus (W. Curtis) Jeps. subsp. aurantiacus [Scrophulariaceae]), toyon (Heteromeles arbutifolia (Lindl.) M. Roem. [Rosaceae]), coffeeberry (Frangul...

Cadophora species are reported from grapevine (Vitis vinifera L.) in California, South Africa, Spain, Uruguay, and Canada. Frequent isolation from vines co-infected with the Esca pathogens (Togninia minima and Phaeomoniella chlamydospora), and confirmation of its ability to cause wood lesions/discoloration in pathogenicity tests, suggest that C. lu...

Novel species of fungi described in the present study include the following from South Africa: Alanphillipsia aloeicola from Aloe sp., Arxiella dolichandrae from Dolichandra unguiscati, Ganoderma austroafricanum from Jacaranda mimosifolia, Phacidiella podocarpi and Phaeosphaeria podocarpi from Podocarpus latifolius, Phyllosticta mimusopisicola from...

Cadophora species are recently acknowledged as putative trunk pathogens in independent investigations from California, South Africa, Spain, Uruguay, and Canada. In particular, Cadophora luteo-olivacea has been associated with vines affected by Petri disease and Esca, and indeed has been shown to cause the characteristic black streaking in controlle...

Phytophthora tentaculata was recovered from sticky monkey flower (Mimulus aurantiacus) at a California native plant nursery in 2012, which was the first detection of P. tentaculata in the USA (Rooney-Latham and Blomquist 2014). Phytophthora tentaculata is listed as a threat to nurseries and forests in United States federal New Pest Response Guideli...

Arugula (Eruca vesicaria subsp. sativa (Mill.) Thell. is a Cruciferous plant used for culinary purposes. From 2012 to 2013, a foliar disease seriously impacted the growth and quality of about 0.1 ha of hydroponically grown arugula at a Santa Barbara County nursery. Samples of affected arugula seedlings exhibited adaxial and abaxial symptoms of mott...

In July 2013 in coastal (Santa Barbara County) California, commercial plantings of southern highbush blueberry (Vaccinium corymbosum) developed symptoms of a previously undiagnosed disease. Symptoms consisted of reddening and wilting of foliage, with leaves and small twigs later drying up. The bark of diseased branches was discolored and sunken; re...

Sticky monkey flower plant, Mimulus aurantiacus (Phrymaceae), is a small, perennial shrub that is widely distributed throughout California, especially in coastal and disturbed habitats. It is also found in native plantings in parks and landscapes. In October 2012, nearly all the M. aurantiacus plants grown in a Monterey County, CA nursery for a res...

The multi-trophic relationship between insects, yeast, and filamentous fungi is reported on sabal palm (Sabal palmetto (Walter) Lodd. ex Schult. & Schult. f.). Gut content analyses and observations of adult and larval feeding of the sap beetle Brachypeplus glaber LeConte indicate that niche partitioning of fungal food substrata occurs between adult...

Olive (Olea europaea) is a widely planted evergreen tree primarily grown for its oil, fruit for pickling, and landscape appeal in Mediterranean and temperate climates. California produces most of the olives grown in the United States; its industry was valued at $53 million in 2011 (4). In 2005 and 2008, fruit spotting occurred on coratina and picho...

Cinnamomum camphora (Lauraceae) is an evergreen shade tree grown in many parts of the United States, including California. From 2007 to 2011, an arborist working in a residential neighborhood in Mill Valley (Marin Co.) noticed several camphor trees with branch dieback and decline. Affected trees had patchy, irregular cankers on the branches and sho...

Phormium colensoi Hook.f. (syn. P. cookianum), New Zealand flax, (family Xanthorrhoeaceae) is popular in ornamental landscapes in the United States because of its sturdy blade-like foliage available in diverse colors. In February 2012, the Oregon State University Plant Clinic received three potted plants of P. colensoi ‘Black Adder’ from a commerci...

Huanglongbing (HLB), also known as citrus greening, is one of the most destructive citrus diseases worldwide and is seen as a major threat to the multimillion dollar citrus industry in California. The vector of the two bacterial species associated with this disease, Candidatus Liberibacter asiaticus and Ca. L. americanus, is the Asian citrus psylli...

Chinese fringe flower is a popular landscape plant in California for its red evergreen foliage and its showy red flowers in the spring. In April 2007, a sample was submitted to the California Department of Food and Agriculture diagnostic laboratory from Sacramento County as part of an inspection of a nursery for Phytophthora ramorum. A sample was t...

Euphorbia tithymaloides (Euphorbiaceae; known as 'Jacob's ladder,' 'Devil's Backbone') is a perennial, succulent spurge, grown primarily as a border plant in ornamental landscapes. In June 2011 and February 2012, the California Department of Food and Agriculture Plant Pest Diagnostics Lab, Sacramento, CA, received an unusual powdery mildew sample o...

Between 2001 and 2007, samples from three California native plants showing canker symptoms were submitted to the California Department of Food and Agriculture's Plant Pest Diagnostics laboratory. Giant sequoia (Sequoiadendron giganteum) and coast redwood (Sequoia sempervirens) showed branch cankers and dieback, whereas tanoak (Lithocarpus densiflor...

In April 2011, commercial garlic (Allium sativum) in Monterey County, CA showed symptoms of an undocumented disease. Bulb and stem sheaths were dark, decayed, and sloughing off the plants. Dissection of diseased sheaths revealed black hyphae between layers. Lower leaves wilted, turned tan, and dried up. Disease occurred in small patches scattered i...

The majority of United States sunflower production is in seven Midwestern states, but hybrid planting seed is almost exclusively produced in California. Due to the lack of summer rains and furrow irrigation, California-produced seed is relatively disease free and thus it regularly meets phytosanitary restrictions imposed by many countries. For the...

Passiflora edulis Sims f. edulis, known as purple passion fruit, is a woody, perennial vine that is grown for its attractive two-part flower and its purple, edible fruit (4). In November 2009, passion fruit vines were collected during a regulatory nursery inspection in Santa Barbara County and submitted to the California Department of Food and Agri...

Cosmos (Cosmos bipinnatus Cav.) is an annual that is grown for cut flowers or as a landscape bedding plant. In late July 2009, cosmos plants were collected from a 0.4-ha field in Santa Barbara County, CA and submitted to the California Department of Food and Agriculture's Plant Pest Diagnostics Laboratory. Plants showed symptoms of chlorosis, wilti...

The genus Scilla (Hyacinthaceae) includes more than 50 species of perennial, flowering bulbs grown in landscapes worldwide. In December 2000 and May 2009, an unknown leaf spot disease on Scilla peruviana was submitted to the California Department of Food and Agriculture Plant Pest Diagnostic Lab. Samples were collected during routine phytosanitary...

The genus Acanthus (Acanthaceae) includes ~30 herbaceous, perennial species grown for their attractive foliage and flower spikes. Between June and December 2009 the CDFA Plant Pest Diagnostics Lab in Sacramento, CA received multiple leaf spot disease samples on Acanthus spinosus and A. mollis, commonly known as bear's breeches. Samples were collect...

The botryosphaeriaceous fungus Diplodia corticola A. J. L. Phillips, Alves & Luque was shown to be the most prevalent canker and dieback pathogen in cork oaks (Quercus suber L.) in the Iberian Peninsula causing a general decline of the trees as a consequence of canker formation in the trunks (1). In addition, D. corticola has been recently reported...

Fenugreek (Trigonella foenum-graecum) is a member of the Fabaceae family and is grown worldwide for culinary and medicinal purposes. The leaves are used as an herb while the seeds are used whole, ground as a spice, or germinated and used as sprouts. In November 2008, a fenugreek plant exhibiting leaf spotting and severe stunting was submitted to th...

Sweet basil (Ocimum basilicum) is a culinary herb grown in fields and greenhouses in California. In August of 2008, samples were submitted to the San Diego County Plant Diagnostic Laboratory with a grayish brown, downy growth that covered areas of the abaxial side of the leaf. Early symptoms included leaf chlorosis followed by the appearance of sca...

In November 2006, trees of Italian alder (Alnus cordata) were observed declining in association with bleeding trunk cankers in a commercial landscape in Foster City, CA. A species of Phytophthora was isolated on PARP selective medium from the leading edge of the cankers. The Phytophthora species was homothallic with primarily paragynous antheridia...

During the 2006 growing season, grape berries in several Red Globe vineyards in Kern County, California were found exhibiting black fungal sporulation and typical sour rot symptoms. Symptoms included berry cracking and leakage along with a pungent vinegar smell. In California, sour rot (also known as summer bunch rot) has been attributed to a compl...

Togninia minima is an important pathogen causing esca and grapevine declines worldwide. Although perithecia of T minima have been produced in the laboratory, their presence in diseased vineyards has not been shown. In our study, perithecia of T minima were found on grapevines in the field in five California counties. Perithecia were clustered on de...

Esca and Petri diseases on grapevine are caused by Phaeomoniella chlamydospora and species of Phaeoacremonium including P. aleophilum, P. viticola, P. angustius, P. parasiticum, P. inflatipes, P. rubrigenum, and P. mortoniae. The teleomorphs of P. aleophilum and P. mortoniae have been recently confirmed as Togninia minima(Tul. & C. Tul.) Berl. (2,3...

Esca (black measles) and Petri disease (young esca) are two of the most destructive diseases of grapevines in California and other grape-producing countries. This disease is now known to be caused by multiple species of Phaeoacremonium including P. aleophilum, P. angustius, P. parasiticum, P. rubrigenum, and P. mortoniae. The teleomorph of P. aleop...

Phaeoacremonium is a recently described genus of the hyphomycetes and includes species associated with grapevine (Vitis vinifera) declines worldwide. Spores of Phaeoacremonium spp. have been trapped in infested vineyards, but neither asexual nor sexual fruiting structures have been observed in the field. Mating studies were carried out to determine...

Esca and grapevine decline are important diseases affecting both young and mature grapevines worldwide. In California, these diseases are caused primarily by the fungal pathogens Phaeomoniella chlamydospora and Phaeoacremonium aleophilum. Perithecia of Togninia minima, the newly-described teleomorph of Phaeoacremonium aleophilum, were produced by m...

Root rots of grapevine in California are caused by several soilborne pathogens. While root rot in vineyards in general has been considered to be a relative minor problem, nearly all root diseases have increased in incidence and severity since the introduction of rootstocks resistant to Phylloxera. Pathogens such as Phytophthora spp. and Armillaria...

Autoclaved sand was inoculated with Phaeoacremonium inflatipes, P. aleophilum and P. chlamydosporum. Single bud cuttings of grapes of cv. Chardonnay were placed in inoculated sand and incubated for three weeks at 27°C. P. inflatipes was isolated from 66%, P. aleophilum from 59% and P. chlamydosporum from 7% of cultured cuttings. The effect of infec...