Silicon supplementation can reduce infestation by azalea lace bug-(Hemiptera: Tingidae).

The azalea lace bug (ALB), Stephanitis pyrioides (Scott) (Hemiptera: Tingidae), is a pest of azaleas and rhododendrons. The application of silicon (Si) to plants has been shown to accumulate in other plants and enhance defense to other plant pests. We evaluated whether Si applications decreased ALB infestation on rhododendron leaves and increased Si accumulation in leaves.

The Effect of Boxwood Leaf Volatiles on Conidial Germination of , the Causal Agent of Boxwood Blight.

The fungal pathogen causes boxwood blight and is a significant threat to the boxwood industry, as well as historic boxwood gardens. The pathogen produces conidia in sticky masses that are splash dispersed, which germinate and infect through stomata on the leaves or stems, causing leaf spots and stem lesions. Despite its ability to cause severe infections on boxwood plants, the pathogen often has a low germination rate on artificial media under lab conditions.

Fungicide Sensitivity of Isolates from the Washington Red Raspberry Industry.

is an important pathogen causing Phytophthora root rot of red raspberries worldwide. Management of this disease is partially achieved with fungicides, but efficacy has been low, and growers are concerned about fungicide resistance. To determine whether fungicide resistance is developing, species were isolated from 26 raspberry fields with root rot, identified, and evaluated for sensitivity to four fungicides: mefenoxam, phosphorous acid, oxathiapiprolin, and dimethomorph.

Temperature and Fungicide Sensitivity in Three Prevalent Species Causing Phytophthora Root Rot in Rhododendron.

Temperature is an important environmental variable affecting spp. biology. It alters the ability of species to grow, sporulate, and infect their plant host, and it is also important in mediating pathogen responses to disease control measures.

Rapid and Scalable DNA Extraction and Real-Time PCR Assay from Boxwood Tissue for the Detection of , Causal Agent of Boxwood Blight.

Boxwood blight can be challenging to detect in the field, especially when symptoms are mild, thus requiring large numbers of plants to be screened. Therefore, a rapid diagnostic assay that can detect the pathogen from large amounts of plant tissue would be useful. Here, we present a crude DNA extraction protocol that is rapid and scalable.

Cool Temperatures Favor Growth of Oregon Isolates of and Increase Severity of Boxwood Blight on Two Cultivars.

Controlled environment experiments were conducted to evaluate the effects of temperature on mycelial growth and the effects of temperature and infection period on boxwood blight severity. In experiment 1, 15 Oregon isolates (representing five genotypes) were grown on potato dextrose agar (PDA) and malt extract agar (MEA) at six temperatures from 5 to 30°C. Growth (culture diameter) was measured after 2 weeks.

Is Disease Induced by Flooding Representative of Nursery Conditions in Rhododendrons Infected with or ?

The degree of flooding commonly used to induce disease in Phytophthora root rot studies rarely occurs in container nurseries. Instead, over-irrigation and poor drainage result in plants periodically sitting in shallow pools of water. Rhododendron plants were grown in a noninfested substrate or substrate infested with or to determine whether root rot induced by flooding represents disease that occurs under simulated nursery conditions when plants are in a shallow pool of water (saucers), or are allowed to freely drain and maintained at ∼75% container capacity (CC).

Optimizing Inoculum Production Methods for Infesting Soil with Species.

Inoculum production is an important part of conducting research with soilborne species. One common method is to incubate cultures in nutrient-amended vermiculite. However, inoculum levels often vary among batches of inoculum, even when production methods remain the same, and incubation typically takes ≥6 weeks, increasing risks for delayed experiments if the resulting inoculum level is too low.

Virulence of Five Species Causing Rhododendron Root Rot in Oregon.

Phytophthora root rot is a destructive disease of rhododendron that causes substantial losses of this nursery crop in infested field and container production areas. Historically, was considered the main causal agent of the disease. However, a recent survey of soilborne species from symptomatic rhododendrons in Oregon revealed that is more common than , and that several other species may be involved.

Species Differ in Response to Phosphorous Acid and Mefenoxam for the Management of Phytophthora Root Rot in Rhododendron.

Phytophthora root rot, caused by many soilborne spp., is a significant disease affecting the $42 million rhododendron nursery industry. Rhododendron growers have increasingly reported failure by two systemic fungicides, phosphorous acid and mefenoxam, to adequately control root rot.

Growth, Sporulation, and Pathogenicity of the Raspberry Pathogen Under Different Temperature and Moisture Regimes.

Phytophthora root rot of raspberry, which is mostly caused by , is a significant issue for the Washington State red raspberry industry. Considered a cool weather pathogen, it is often assumed that it is most active and infective during the cool, wet winters of the region when soil temperatures range from 5 to 10°C; however, there are little data to support this view. More recent research has found that symptoms of root disease during late summer were strongly associated with .

Soilborne and Diversity From Rhododendron in Propagation, Container, and Field Production Systems of the Pacific Northwest.

Rhododendron root rot is a severe disease that causes significant mortality in rhododendrons. Information is needed about the incidence and identity of soilborne and species causing root rot in Pacific Northwest nurseries in order to better understand the disease etiology and to optimize disease control strategies. The last survey focusing solely on soilborne oomycete pathogens in rhododendron production was conducted in 1974.

Population Structure of on in Oregon Nurseries.

is a recently described plant pathogen, formerly recognized as . Recent sampling of Pacific Northwest nurseries frequently encountered this pathogen, and it has been shown to be among the most damaging pathogens on ornamentals. We characterized the population structure of in a survey of four Oregon nurseries across three different counties with focus on hosts.

Variation in Disease Severity Caused by Phytophthora cinnamomi, P. plurivora, and Pythium cryptoirregulare on Two Rhododendron Cultivars.

Rhododendrons are an important crop in the ornamental nursery industry, but are prone to Phytophthora root rot. Phytophthora root rot is a continuing issue on rhododendrons despite decades of research. Several Phytophthora species are known to cause root rot, but most research has focused on P.

Chicoric acid: chemistry, distribution, and production.

Though chicoric acid was first identified in 1958, it was largely ignored until recent popular media coverage cited potential health beneficial properties from consuming food and dietary supplements containing this compound. To date, plants from at least 63 genera and species have been found to contain chicoric acid, and while the compound is used as a processing quality indicator, it may also have useful health benefits. This review of chicoric acid summarizes research findings and highlights gaps in research knowledge for investigators, industry stakeholders, and consumers alike.

Nitrogen mobilization, nitrogen uptake and growth of cuttings obtained from poplar stock plants grown in different N regimes and sprayed with urea in autumn.

Nitrogen mobilization, nitrogen uptake and growth of cuttings obtained from poplar stock plants fertigated with different nitrogen (N) treatments and sprayed with urea in autumn were studied. Stock plants propagated from poplar cuttings were trained to a single shoot and fertigated with 0, 5, 10, 15 or 20 mmol l(-1) N during the first growing season. In October, a subset of stock plants from each N fertigation treatment was sprayed twice with either 3% urea or water, and overwintered outside.

Nitrogen absorption, translocation and distribution from urea applied in autumn to leaves of young potted apple (Malus domestica) trees.

We studied the absorption, assimilation, translocation and distribution of nitrogen (N) from urea applied in autumn to leaves of 1-year-old potted Fuji/M26 apple (Malus domestica Borkh) trees. In early October, all leaves of each tree were painted with either 3% urea (enriched to 10 atom % with 15N) or water (control trees). Four trees were harvested before the treatment and N and amino acid contents were determined.