Agrocybe aegerita is an important mushroom cultivated in Korea, with good feel and a peculiar fragrance. A. aegerita can be cultivated throughout the year using culture bottles but is more susceptible to contamination than other mushrooms. Twenty-two pathogens were isolated from the fruiting bodies and compost of A. aegerita, and seven isolates were isolated from Pleurotus ostreatus to compare with the A. aegerita isolates, collected from Gimje, Iksan, Gunsan of Chonbuk, and Chilgok of Gyeongbuk Province in 2009. These isolates were identified based on morphological and molecular characteristics. Of the 29 isolates, 26 were identified as Trichoderma spp. and the remaining three were Aspergillus spp., Mucor spp., and Penicillium spp. A phylogenetic analysis revealed that the 26 isolates of Trichoderma were divided into four taxa, namely T. harzianum, T. pleuroticola, T. longibrachiatum, and T. atroviride. Among the Trichoderma spp., 16 isolates (55.2%) were identified as T. harzianum, six as T. pleuroticola (20.7%), two as T. longibrachiatum, and the remaining two were T. atroviride.
The socio-network activities for regional governments, agricultural research institutes, developing agencies and policy makers of any countries are very crucial and important to take into account the root cause of current problems faced by farmers. The survey was conducted in South Korea during the period January, 2008 to August, 2012 in order to shed light on prevalence of different diseases on watermelon in different regions and to better understand farmers' knowledge and perceptions for following watemelon's growing procedures and practices. A total of 590 cases were reported on 573 watermelon growers with highest 87.1% in Jeonbuk, 4.7% in Jeonnam, and 8.2% in other regions such as Gyeongbuk, Gyeongnam, Chungnam, Gwangju, Gyeonggi, Daegu, Gangwon, Changwon and Seoul. The maximum percentages of cases recorded were related to diseases and insect pest (38.6%) followed by physiological disorder (29.7%), cultural practices (18.8%), soil and fertilizer (9.0%), herbicide (2.9%) and others (1.0%). It was observed that the manifestation aspects of the diseases were changed due to increasing in proportion of 'in-facility' cultivation to 12,995 ha compared to 'open-field' cultivation (2,722 ha). The present survey revealed the necessity to reduce the damages incurred at watermelon farms as soon as possible through the breeding program to develop resistant cultivar, use of pathogen-free propagating plants, and efficient prevention of pathogen by regular monitoring of watermelon plants at farms.
, a root endoparasite of several cereal species, is considered to be non-pathogenic but serves as a vector of various plant viruses belonging to the genera ,, and . Specifically, it reduces barley productivity by transmitting the (BaYMV). To date, due to its obligate biotrophic property, no artificial culturing of was reported and its quantification was also technically challenging. Here, we developed a novel and simple method to infect within sterile barley roots in contamination free by preparing nearly pure zoospore inoculum. Such artificial maintenance of was verified based on the presence of various developmental stages in infected barley roots under microscope. In addition, the population of resting spores in host tissue was determined by establishing standard curve between manually counted number of spores and C values of 18S rDNA amplification using quantitative real-time PCR. Furthermore, it was validated that standard curve generated was also applicable to estimate the abundance of in soil environments. In conclusion, the present study would help to generate a system to investigate the etiological causes as well as management of plant diseases caused by and BaYMV in tissue and soil.
It was identified as a sharp eyespot (Rhizoctonia cerealis) that the isolates from abnormal symptoms in wheat that showed yellowing leaves, necrotic spot on stem base and dead tillers. These isolates have slower growth property and fewer mycelia than Rhizoctonia solani AG-1(1A) (KACC 40106). They showed binuclear cell, same media cultural and DNA characteristics to R. cerealis. They caused same symptoms on leaves and stem base appeared in artificial inoculation test, comparing to diseased wheat fields and also affect to maturing of kernels. They have optimal growth temperature and acidity on the artificial media as 20~25 o C and pH 5~7, respectively. In the investigation of varietal resistance of Korean winter cereal crops to sharp eyespot, there was no resistant in wheat cultivars that all materials infected over 20% diseased ratio. 12 cultivars including 'Anbaekmil', however, considered to moderate resistance with 20 to 30% infection ratio. The others crops using in feeding, whole crop barley, oat, rye and triticale were resistant below 15% diseased degree except the rye that showed over 50% infection rate. It was the first evaluation to sharp eyespot resistance for the Korean feeding crop cultivars. Most tested Korean barley cultivars for malting and food were moderate and susceptible to the sharp eyespot. Only 3 hulled barley, 'Tapgolbori', 'Albori' and 'Seodunchalbori', showed resistance with less than 10% diseased ratio. All tested naked barley cultivars showed susceptible response to the disease.
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