Californian thistle (Cirsium arvense): endophytes and Puccinia punctiformis.

Californian thistle (Cirisum arvense) is a troublesome weed in pastures and cropping systems. The fungal biocontrol agent Puccinia punctiformis, commonly referred to as thistle rust, performs inconsistently on C. arvense. Problems with P. punctiformis establishment and control of C. arvense may be attributable to differing plant endophytic populations in various environments. This article provides an overview of the relationships between endophytes and their host, but also between endophytes and pathogens with a focus on rust pathogens. This review provides insights into reasons why P. punctiformis performs inconsistently and identifies gaps in our knowledge. Filling these gaps may help to improve performance of this classical fungal biocontrol agent. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

A Horticultural Cuticle Supplement Can Impact Quality Characters and Drosophila suzukii Damage of Several Small and Stone Fruit.

Surface wax and other cellular building blocks play an important role in preserving fruit integrity from biotic and abiotic adversities. Huge energy expenses are made by plants to place these protective compounds onto the epidermal cuticle. Sprayable plant and fruit coatings have been developed to protect plant tissues from environmental stresses, pathogens, and arthropods. The aim of this study was to determine if an experimental cuticle supplement containing waxes can affect fruit quality parameters such as firmness and size of various crops. Cherry, blueberry, and winegrape plants treated with the cuticle supplement showed significant increases in berry firmness ranging from 4.6 to 11.6%. No quality benefits were however observed on blackberry. Cuticle supplement applications did not significantly affect berry size. Laboratory trials resulted in a 54% mean reduction in a model pest insect i.e., Drosophila suzukii egg laying on blueberry. Short-duration field trials over 72 ±â€…2 to 96 ±â€…2 h on commercial-standard blueberry bushes resulted in 50-93.4% reductions of D. suzukii damage. Longer-term field trials on cherry and blueberry challenged with egg-laying D. suzukii showed reductions of damage ranging from 45 to 95%, up to 30 d after initial cuticle supplement applications. These results indicate that the cuticle supplement significantly alters berry firmness and reduces D. suzukii damage under commercial production conditions. One factor that may contribute to this reduction includes improved fruit quality parameters. The current work serves to expand integrated pest management options to control D. suzukii populations in commercial field settings.

Evaluation of Organic, Food-Grade Hydrophobic Coatings for Suppressing Oviposition and Increasing Mortality of Western Cherry Fruit Fly (Diptera: Tephritidae).

Newer organic options for protecting fruit from tephritid fruit fly attack are needed to reduce extensive insecticide use. Here, we evaluated organic, food-grade hydrophobic coatings that help protect sweet cherries (Prunus avium L.) from water-induced cracking for suppressing attack on cherries by western cherry fruit fly, Rhagoletis indifferens Curran (Diptera: Tephtitidae), as well as for their effects on fly mortality. Three formulations of coatings called HydroShield 13.20, 13.22, and 13.28 that form invisible elastic barriers on cherries and that consist of complex carbohydrates, fatty acids and occlusive agents, solvents, emulsifiers, emollients, surfactants, and other ingredients were tested. In the laboratory, fly visits on and oviposition in HydroShield-coated cherries were 66.1-92.8% and 59.1-99.5% lower, respectively, than in controls. The mean number of dead female flies exposed to HydroShield-coated cherries was 69.4-94.6% greater than of females exposed to control cherries. In the field, three sprays of HydroShield 13.22 and 13.20 on sweet cherry trees in 2020, when fly densities were high, reduced larval infestations in cherries by 32.1% and 31.8%, respectively. In the field in 2021, when fly densities were lower, three sprays of HydroShield 13.22 and 13.28 reduced infestations in cherries by 90.5% and 86.8%, respectively, but sprays also reduced cherry size and toughened cherries. HydroShield formulations show promise in protecting sweet cherry from attack by R. indifferens, but further testing is needed to improve formulations so that they suppress fly oviposition without affecting cherry quality.

Establishment in an Introduced Range: Dispersal Capacity and Winter Survival of Trissolcus japonicus, an Adventive Egg Parasitoid.

The herbivorous brown marmorated stink bug, Halyomorpha halys, has spread globally, and one of its key parasitoids, Trissolcus japonicus, has recently been detected in the pest's introduced range. For an exotic natural enemy to impact its targeted host in a novel environment, it must disperse, locate hosts, and potentially be redistributed to susceptible sites. Through intentionally releasing T. japonicus across four Oregon eco-regions, we investigated an introduced parasitoid's dispersal capacity in urban sites and in two perennial crops, hazelnut and raspberry. In a second paired field and laboratory study, we investigated T. japonicus survival in different plant materials. Within three days of release, adult T. japonicus located host egg masses at 45% of sites and, one year later, were detected at 40% of release sites. Areas where released wasps survived winter were mostly urban or semi-natural. In commercial crop release experiments, we recovered the highest percentage of wasps in raspberry within 5 m of the release site but found no statistical difference in dispersal distance with some wasps dispersing up to 50 m. Adult parasitoids survived up to 16 weeks outdoors in the winter, with greater survival over time in bark compared to leaf litter. Wasp survival remained above 50% over the course of a simulated winter environment without precipitation. Our work affirms the continuation of H. halys parasitism by T. japonicus in novel environments and provides insight into the high population sizes necessary to survive winter and locate host egg masses the following season.

Spatial Associations of Vines Infected With Grapevine Red Blotch Virus in Oregon Vineyards.

Spread and in-field spatial patterns of vines infected with grapevine red blotch virus (GRBV) were documented in Oregon vineyards using field sampling, molecular diagnostics, and spatial analysis. Grapevine petiole tissue collected from 2013 to 2016 was tested using quantitative polymerase chain reaction for GRBV. At Jacksonville in southern Oregon, 3.1% of vines were infected with GRBV in 2014, and GRBV incidence reached 58.5% of study vines by 2016. GRBV-infected plants and GRBV-uninfected plants were spatially aggregated at this site in 2015, and infected plants were spatially associated between years 2015 and 2016. In a southern Oregon vineyard near Talent, 10.4% of vines were infected with GRBV in 2014, and infection increased annually to 21.5% in 2016. At Talent, distribution of the infected vines was spatially associated across all years. GRBV infection was highest at Yamhill, in the Willamette Valley, where 31.7% of the tested vines had GRBV infection in 2014. By 2016, 59.2% of the vines tested positive for GRBV. Areas of aggregation increased and were spatially associated across all years. From 2013 to 2015, GRBV was not detected at Milton-Freewater in eastern Oregon. Spatial patterns of GRBV infection support evidence of spread by a mobile insect vector. GRBV is a significant threat to Oregon wine grape production because of its drastic year-over-year spread in affected vineyards.

Consumption of Quercetin and Quercetin-Containing Apple and Cherry Extracts Affects Blood Glucose Concentration, Hepatic Metabolism, and Gene Expression Patterns in Obese C57BL/6J High Fat-Fed Mice.

BACKGROUND: Intake of polyphenols and polyphenol-rich fruit extracts has been shown to reduce markers of inflammation, diabetes, and hepatic complications that result from the consumption of a high-fat (HF) diet. OBJECTIVE: The objective of this study was to determine whether mice fed polyphenol-rich apple peel extract (AE), cherry extract (CE), and quercetin, a phytochemical abundant in fruits including apples and cherries, would modulate the harmful effects of adiposity on blood glucose regulation, endocrine concentrations, and hepatic metabolism in HF-fed C57BL/6J male mice. METHODS: Groups of 8-wk-old mice (n = 8 each) were fed 5 diets for 10 wk, including low-fat (LF; 10% of total energy) and HF (60% of total energy) control diets and 3 HF diets containing polyphenol-rich AE, CE, and quercetin (0.2% wt:wt). Also, an in vitro study used HepG2 cells exposed to quercetin (0-100 µmol/L) to determine whether intracellular lipid accumulation could be modulated by this phytochemical. RESULTS: Mice fed the HF control diet consumed 36% more energy, gained 14 g more body weight, and had ∼50% elevated blood glucose concentrations (all P < 0.05) than did LF-fed mice. Mice fed HF diets containing AE, CE, or quercetin became as obese as HF-fed mice, but had significantly lower blood glucose concentrations after food deprivation (-36%, -22%, -22%, respectively; P < 0.05). Concentrations of serum C-reactive protein were reduced 29% in quercetin-fed mice compared with HF-fed controls (P < 0.05). A qualitative evaluation of liver tissue sections suggested that fruit phytochemicals may reduce hepatic lipid accumulation. A quantitative analysis of lipid accumulation in HepG2 cells demonstrated a dose-dependent decrease in lipid content in cells treated with 0-100 µmol quercetin/L (P < 0.05). CONCLUSIONS: In mice, consumption of AE, CE, or quercetin appears to modulate some of the harmful effects associated with the consumption of an obesogenic HF diet. Furthermore, in a cell culture model, quercetin was shown to reduce intracellular lipid accumulation in a dose-dependent fashion.