For crop improvement, DNA manipulation techniques provide new approaches to generate useful plants which carry and express additive foreign genes. Recently, agronomically useful genes, such as herbicide, viral, fungal and insect resistance genes, have been introduced to both of dicot and monocot plants, and additive acquired resistance against the chemical and biological stresses were found in these tansgenic plants. Because resistance genes against phytopathogenic bacteria are limited in main crops, generation of transgenic plants which are resistant to bacterial disease have been long-waited. In addition, criticism against environmental pollution by usage of agricultural antibiotics to protect bacterial infection has increased. In this context, transgenic strategy to generate resistant crops against phytopathogenic bacteria would be important now. In this paper, genetic sources for introduced gene constructs and outline of generated resistant transgenic plants against phytopathogenic fungi and bacteria are described.
Long-mat type rice seedlings were treated before transplanting with either tricyclazole or carpropamid granules for rice blast. Treatment of the fungicides before transplanting was effective against rice blast in the field. Bakanae disease did not appear on seedlings in the hydroponic nursery bed but appeared severely from seven weeks after transplanting until the heading stage in the field. Data clearly suggest that the development of bakanae disease is different from the ordinary transplanting method.
In 1997, Cucumber mosaic cucumovirus (CMV) was detected from Sandersonia showing stunt and necrotic streak symptoms in Chiba Prefecture. The virus was confirmed by host range, electron microscopy and enzyme-linked immunosorbent assay. This is the first report on a virus disease of Sandersonia.
A new disease of cymbidium was found in Japan in the prefectures of Yamanashi, Shizuoka, Kochi, Shiga, Saitama and Yamaguchi from 1992 to 1998. Dark brown to black lesion appeared on the base of the leaves, dry rot was seen on pseudobulb and rot was seen on roots. Disease progress was slow, so that the plant grew up suppressively. The causal pathogen was identified as Fusarium solani on the basis of its morphology, and the common name of the disease, dry rot, was proposed.
Verticillium wilt of dahlia Dahlia×cultorum Thorsr. et Reis., small globethistle Echinops ritro L. and gayfeather Liatris spicata (L.) Willd. occurred in Tokyo Metropolis in 1997. The causal fungus isolated from the diseased plants was identified as Verticillium dahliae Klebahn by morphological observations and inoculation tests. This is the first report on these diseases in Japan.
Southern blights of sweet william silene, Silene armeria L., beggar-ticks, Bidens laevis (L.) B. S. P. and heliopsis, Heliopsis helianthoides (L.) Sweet occurred in Tokyo Metropolis in 1997. The causal fungi isolated from each diseased plant were identified as Sclerotium rolfsii Saccardo by morphological observations and inoculation tests. These are the first reports on the diseases in Japan.
Leaf blight of beard-tongue Penstemon hybrid and stem and root rot of safflower Carthamus tinctorius L. and small globethistle Echinops ritro L. occurred in Tokyo Metropolis in 1997. A Rhizoctonia species isolated from the diseased plants was identified as Rhizoctonia solani Kühn. Inoculation tests showed that the fungus was the causal agent of these diseases. This is the first report on these diseases in Japan.
Phoma rot of carpet bugle Ajuga reptans L. occurred in Tokyo Metropolis in 1996. The causal fungus isolated from the diseased plant was identified as Phoma eupyrena Saccardo by morphological observations and inoculation tests. This is the first report on the disease in Japan.
Leaf spot of English ivy Hedera helix L. and dog-hobble Leucothoe walteri (Willd.) Melvin occurred in Tokyo Metropolis between 1995 and 1996. The causal fungus isolated from the diseased plants was identified as Guignardia sp. by morphological observations and inoculation tests. This is the first report on the occurrence of these diseases in Japan.
Leaf spot of nandina, Nandina domestica Thunb., and Japanese spurge, Pachysandra terminalis Sieb. et Zucc. occurred in Tokyo Metropolis in 1996. The causal fungus isolated from the diseased plants was identified as Phyllosticta sp. by morphological observations and inoculation tests. This is the first report on the occurrence of these diseases in Japan.
Effectiveness of control by the application of Nitenpyram granule in soil against Liriomyza trifolii (Burgess) was evaluated by performing laboratory test and field tests on both tomato and chrysanthemum plants in greenhouses. The control effect of Nitenpyram granule against L. trifolii by a laboratory test was perfect. In the case of field tests Nitenpyram granule was more effective than Acephate granule and Acetamiprid granule when it was applied in the planting holes for tomato seedlings in the greenhouse. Nitenpyram was as effective as Acephate granule when it was applied on the soil just after planting of chrysanthemum in the greenhouse.
Paecilomyces fumosoroseus preparation (PFR-97™ 20% WDG) was applied three times weekly against Bemisia argentifolii and Trialeurodes vaporariorum on tomato in greenhouses in July in Experiment 1 and May-June in Experiment 2, respectively. In Expt. 1, effective control was not obtained in some period because of high temperature (>35°C) and insufficiency of high humidity (>80%). In Expt. 2, the most effective control was obtained due to optimal temperature and humidity.
We studied on the effects of the ultraviolet ray abosorbable films on occurrence and activity of Liriomyza trifolii, Bemisia argentifolii and their parasitoids: Diglyphus isaea, Dacnusa sibirica, Encarsia formosa and Eretmocerus californicus. In laboratory tests, all the tested insects avoided entering and/or staying in the UV ray eliminated space. In green-houses covered with UV ray absorbable films, D. isaea and E. formosa increased as in the greenhouse covered with a regular film.