Leaf spot disease on Juglans regia caused by Ragnhildiana diffusa in China

Juglans regia L. is commercially important for its edible nuts, which is a major species of walnut trees in Sichuan Province (Luo et al. 2020). In September 2021, brown leaf spot symptoms were observed on roughly 75% of 60 J. regia trees surveyed in an orchard of Chongzhou city (30°40’6”N, 103°40’18”E). Initially, the lesions measuring […]

Trunk rot of Juglans regia caused by Myrmaecium fulvopruinatum in China

Walnut (Juglans regia) is a deciduous tree of the Juglandaceae family, widely cultivated in China, and provides value in a variety of ways, including the usage of the wood and nuts, and offers substantial economic, social, and environmental advantages (Wang et al, 2017). Nevertheless, a fungal disease of causing walnut trunk rot was observed in […]

First Report of Anthracnose on Juglans regia Caused by Colletotrichum siamense in Korea.

Walnut (Juglans regia) is one of the main tree crops cultivated for nut production in South Korea with an estimated production of about 1,189 tons per year (Korea Forest Service 2020). In August 2021, anthracnose symptoms, including dark, depressed, irregularly shaped lesions on fruits and leaves of walnut cv. Sinlyeong, were observed at three orchards […]

High-Pressure Carbon Dioxide Use to Control Dried Apricot Pests, Tribolium castaneum and Rhyzopertha dominica, and Assessing the Qualitative Traits of Dried Pieces of Treated Apricot.

One of the new ways of warehouse pest control is the carbon dioxide treatment, which had no residues on the target products. In the present research, at first, CO2 gas was applied to control two important pest species infesting dried apricots. Dry apricots infested with adults of Tribolium castaneum (Herbst) or Rhyzopertha dominica (F.) were exposed to CO2 gas pressures correspond […]

Assessment of Semiochemical Repellents for Protecting Walnut Trees From Walnut Twig Beetle (Coleoptera: Curculionidae) Attack in a Commercial Orchard Setting in California

The walnut twig beetle, Pityophthorus juglandis Blackman, the vector of thousand cankers disease (TCD), poses a significant threat to North American walnut (Juglandaceae Juglans) trees. Despite discovery of TCD-related tree mortality over a decade ago, management options are lacking. This study represents the culmination of several years of investigating the chemical ecology of P. juglandis […]

Limited Evidence for Accumulation of Latent Infections of Canker-Causing Pathogens in Shoots of Stone Fruit and Nut Crops in California

Prevalence of latent infections of the canker-causing fungi Botryosphaeria dothidea and species of Cytospora, Diplodia, Lasiodiplodia, Neofusicoccum, and Phomopsis in young shoots of almond, prune and walnut trees in California was studied to test the hypotheses that 1) latent infections accumulate from current-season shoots to 1-year-old shoots in the orchard and 2) there are distinct […]

Effects of Aphicides on Pecan Aphids and Their Parasitoids in Pecan Orchards

Aphids are important pests of pecans. Traditionally, insecticides have been the primary method of management. However, over-reliance and non-judicious use has led to resistance and damage to natural enemy populations. Therefore, frequent assessment of insecticides is necessary in order to monitor resistance development and non-target impacts. Aphicides, flonicamid, sulfoxaflor, and afidopyropen were assessed for their […]

Progression of Kernel Mold on Hazelnut

Hazelnut kernel mold, caused by a number of fungal species, has been a chronic problem in Pacific Northwest hazelnut production areas for many years. Two highly susceptible breeding selections and two commercial cultivars were used to investigate kernel mold development over time and possible correlations with rainfall. Nuts were allowed to naturally fall onto orchard […]

Improved de novo chromosome-level genome assembly of the vulnerable walnut tree Juglans mandshurica reveals gene family evolution and possible genome basis of resistance to lesion nematode

Manchurian walnut (Juglans mandshurica Maxim.) is a synonym of J. cathayensis, a diploid, vulnerable, temperate deciduous tree valued for its wood and nut. It is also valued as a rootstock for Juglans regia because of its reported tolerance of lesion nematode. Reference genomes are available for several Juglans species, our goal was to produce a […]