Plant Disease – International Nut & Dried Fruit Council

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 […]

Alternaria alternata Causing Brown Spot Disease on Walnut in Xinjiang, China.

Walnut is one of the Xinjiang’s characteristic dried fruits and the main source of income for farmers in walnut growing areas. In September 2019, Juglans regia leaves with brown spots were observed in a 10 hm2 orchard in Hotan area, the diseased leaf rate reached more than 25%. The leaf lesions were suborbicular to irregular, […]

First report of Fusarium concentricum as a causal agent of Fusarium leaf blotch on pecan (Carya illinoinensis) in Southeast China.

The economically important nut crop pecan (Carya illinoinensis (Wangenh.) K. Koch) is seriously affected by increasing incidence of fungal disease worldwide (Xiao et al 2021). The top leaves of the pecan variety ‘Pawnee’ in the orchard of Zhejiang A&F University, Zhejiang, China were damaged by massive dark brown plaques in summer to autumn 2021. The […]

First report of leaf spot on pecan caused by Choanephora cucurbitarum in China.

Pecan (Carya illinoinensis K. Koch) is an important and widely planted nut tree species in Jiangsu Province, China (Mo et al. 2018). In July 2020, leaf spot symptoms were frequently observed on pecan in Jurong, Jiangsu Province (119°15’36″E, 32°1’6″N). Disease incidences ranged from 40 to 65% among 150 mature pecan trees from three nurseries. The […]

Biological and Urea Treatments Reduce the Primary Inoculum of Red Leaf Blotch of Almond Caused by Polystigma amygdalinum.

Red leaf blotch (RLB), caused by Polystigma amygdalinum, is considered the most prevalent foliar disease in both traditional and new intensive almond-growing areas in Spain. Since the disease is monocyclic, its control must be based on the reduction of the only source of inoculum-the leaves infected in the previous season and fallen to the ground […]

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 […]

Frequency of Alternaria genotypes resistant to SDHI fungicides in California pistachio orchards determined by real-time PCR.

Real-time PCR methods were developed to quantify the frequency of SDHC-H134R and SDHB-H277Y mutants associated with SDHI resistance in Alternaria populations from pistachio. The linearity of the standard curves demonstrated the applicability in the quantification of the assays. The accuracy and reliability of the qPCR protocols to determine the frequency of mutants in real samples […]

First Report of Colletotrichum fructicola Causing anthracnose on macadamia in China.

Macadamia (Macadamia ternifolia Maiden and Betche) is an important commercial crop in the world and has the reputation of being the king of nuts (Liu et al. 2019). In August 2020, symptoms of anthracnose appeared on leaves of macadamia in Chongzuo, Guangxi Province, China, with an incidence of 15-20%. The disease developed from the edge […]