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Almanac Pests
Plant pests of current importance (potential or existing risk for the European region)
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Viroids from Citrus and Grapevine Trees

Viroids from Citrus and Grapevine Trees | Almanac Pests | Scoop.it

Viroids are important pathogens of many plants. In citrus trees Citrus exocortis viroid (CEVd) and Citrus viroidⅡ(CVd-Ⅱ,known as Hop stunt viroid, HSVd) can cause the dwarf of citrus trees, decrease growth vigor and fruit production. These two viroids also can infect grapevine. However, they usually do not induce any visible symptoms. In this study, the viroids in citrus and grapevine trees grown in China were detected and their molecular characteristics were analysized.

The results showed that 2 samples were infected with CEVd and this was the first report of CEVd from grapevine in China. The infection rate by HSVd was 35%.

Agricultural Science Research Paper, 133 p

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Detection and Sequence Diversity Analysis of Viroids Isolated from ...

Detection and Sequence Diversity Analysis of Viroids Isolated from ... | Almanac Pests | Scoop.it

At present two kinds viroids were reported infected peach. Hop stunt viroid (HSVd) and Peach latent mosaic viroid (PLMVd). PLMVd had been already reported on peach tree of China, but for HSVd this is the first report in peach in China. Photo: PLMVd infected peach.

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A Destructive New Disease of Citrus in China Caused by Cryptosporiopsis citricarpa sp. nov.

A Destructive New Disease of Citrus in China Caused by Cryptosporiopsis citricarpa sp. nov. | Almanac Pests | Scoop.it

Defoliation, dieback and mortality of Satsuma mandarin (Citrus unshiu), as well as kumquat (Fortunella margarita), in Chenggu County, Shaanxi Province, China was first noticed in 2006 and caused substantial economic losses to citrus production. The incidence of leaves infected approached 100% in some badly infected orchards. The disease prevailed only in late winter and early spring, where early symptoms were rounded and target-like spots on leaves. The disease was named target spot. Black conidiomata were observed on the upper surface of the leaves. A Cryptosporiopsis species was consistently recovered from the infected leaves, shoots, and branches. The name Cryptosporiopsis citricarpa sp. nov. is given to accommodate the fungal pathogen in this study.

Plant Disease, Volume 96, Issue 6, Page 804-812, June 2012.

By Li Zhu, Xinghong Wang, Feng Huang, Jinze Zhang, and Hongye Li, Institute of Biotechnology, Zhejiang University, China; Dekuan Ding, Citrus Institute of Chenggu County, and Kevin D. Hyde, Institute of Excellence in Fungal Research, Thailand; King Saud University, College of Science, Botany and Microbiology Department, Saudi Arabia

http://dx.doi.org/10.1094/PDIS-09-11-0775

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First report of HSVd in Jujube trees in China

First report of HSVd in Jujube trees in China | Almanac Pests | Scoop.it

Hybridization and Biological Indexing Results showed that the 2 Jujube tree samples which were collected from the same field of “Jujube tree-pear” intercroping in Qiqiao,Cangzhou were positive for Hop stunt viroid (HSVd). This is the first report of HSVd in Jujube trees in the world

Both of the 2 samples were selected for cloning, sequence analysis of HSVd and then comparing withthe first HSVd sequence (X00009,1983) from the Hop and also the HSVd sequences in GenBank.

Agricultural Science Research Paper, 132 p

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Detection and Sequence Diversity Analysis of Viroids Isolated from Grapevine & Apple

Detection and Sequence Diversity Analysis of Viroids Isolated from Grapevine & Apple | Almanac Pests | Scoop.it

The first report is made about Hop stunt viroid (HSVd), Australia grapevine viroid (AGVd), Grapevine yellow speckle viroid 1 (GYSVd1) and Grapevine yellow speckle viroid 2 (GYSVd2)  in China.

A new viroid was found in grapevine sample, named Chinese grapevine viroid (CGVd), which has less than 90% similarity to GYSVd1 and GYSVd2.

Citrus exocortis viroid (CEVd) was not detected in all the grapevine samples.

Apple scar skin viroid (ASSVd) was detected in apple samples. The sequences of ASSVd Liaoning isolate and Xinjiang isolate have a top similarity with the sequences reported by Puchta.

28 HSVd sequences, 18 GYSVd sequences, 7 CGVd sequences, 8 AGVd sequences, 3 ASSVd sequences, and 5 CBVd1 sequences were deposited into GenBank.

Agricultural Science Research Paper, 166 p

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First Report of a Soft Rot of Philodendron ‘Con-go’ in China Caused by Dickeya dieffenbachiae

First Report of a Soft Rot of Philodendron ‘Con-go’ in China Caused by Dickeya dieffenbachiae | Almanac Pests | Scoop.it

Lin et al.  (2012) has recently made first report on identification of bacterium Dickeya dieffenbachiae in China. Bacteria cause soft rot of Philodendron and can be transffered by plants and growing medium.


Philodendron is a popular foliage plant cultivated in interiorscapes of homes, offices, and malls throughout China. A severe outbreak of a soft rot of Philodendron ‘Con-go’ occurred in Guangzhou, China from 2010 to 2011. The disease was characterized by leaf infections starting as pinpoint spots that are water soaked and yellow to pale brown. The lesions are sometimes surrounded by a diffuse yellow halo. When the humidity is high and temperatures are warm to hot, the spots expand rapidly, becoming slimy, irregular, and sunken with light tan centers, darker brown borders, and diffused yellow margins and may involve the entire leaf in a few days. An invasion of the midrib and larger veins by the causal bacterium often results in advancement into the petiole and stem.

A survey of three areas of production of Philodendron ‘Con-go’ (5 ha) in Guangzhou revealed that 91% of the fields were affected at an incidence ranging from 15 to 30%. Biolog analysis identified the isolates as Pectobacterium chrysanthemi alias Dickeya sp. PCR and other molecular tests followed by bioassey identified Dickeya dieffenbachiae, which ia a causal agens of soft rot of Philodendron ‘Con-go' in China.


 

Lin BR, Shen HF, Zhou JN, Pu XM, Chen ZN, Feng JJ (2012) First Report of a Soft Rot of Philodendron ‘Con-go’ in China Caused by Dickeya dieffenbachiae.- Plant Disease 96(2012)3 p 452. http://dx.doi.org/10.1094/PDIS-09-11-0795

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