Gray mold of celery, Apium graveolens L., occurred on Chichijima in Ogasawara(Bonin) Islands in 2007. The pathogen isolated from the diseased plants was identified as Botrytis cinerea Persoon: Fries. An inoculation test confirmed that this fungus was the causal agent of this disease. This is the first report of this disease in Japan.
Anthracnose of Cacalia delphiniifolia Siebold et Zucc. occurred on Toshima Island of Tokyo Metropolis in 2009. The causal fungi isolated from the diseased plants were identified as Colletotrichum dematium (Persoon:Fries) Grove and Colletotrichum gloeosporioides (Penzig) Penzig & Saccardo. Inoculation tests showed that these fungi were the causal agents of the disease. This is the first report of the disease in Japan.
Rhizopus rot of passion fruit, Passiflora edulis × P. edulis f. flavicarpa, occurred on Chichijima in Ogasawara(Bonin) Islands in 2005. The pathogen isolated from the diseased plants was identified as Rhizopus sp. An inoculation test confirmed that this fungus was the causal agent of this disease. This is the first report of this disease in Japan.
Leaf spot of coneflower (Rudbeckia spp.) and morning glory (Pharbitis nil) occurred in Ibaraki Prefecture in July and November 2007, respectively. Both causal agents were identified as Alternaria alternata. This is the first report on coneflower and morning glory in Japan.
Leaf spot of air plant, Kalanchoe pinnata (Lam.) Pers., occurred on Chichijima in Ogasawara (Bonin) Islands in 2003. The pathogen isolated from the diseased plants was identified as Phoma exigua. An inoculation test confirmed that this fungus was the causal agent of this disease. This is the first report of this disease in Japan.
Two fungal isolates from blighted oregano seedlings in Tsukuba, Japan, in November 2007 were identified as the leaf blight pathogen, Rhizoctonia solani AG-1 IB based on their morphology, anastomosis tests with the reference strain and PCR with the specific primer. Inoculations with the isolates to Origanum vulgare, two cultivars of O. vulgare, O. vulgare subsp. hirtum and O. majorana seedlings, showed that both attacked all cultivars and species, though O. vulgare and O. vulgare subsp. hirtum were relatively tolerant to the pathogen.
Stem rot disease of potted hydrangea (Hydrangea macrophylla (Thunb.) Ser.) occurred in Gunma Prefecture. Two of four isolates from affected hydrangea plants were identified as Phoma exigua Desmaz., a pathogen of leaf spot disease of hydrangea, and the others were identified as Phoma spp. by investigating mycological properties and analyzing DNA sequence of ITS-rDNA region.
The apple snail, Pomacea canaliculata (Lamarck), is an important exotic pest in paddy fields in Japan. In Shizuoka Prefecture after the first occurrence in 1983, the distribution area of the snails has been increasing year by year. We conducted a mark-release-recapture study of the snails in paddy fields with plot-to-plot irrigation to investigate their dispersal ability. The recapture rates were about 60% at two weeks after the release. About 30% to 60% of the snails moved from a released field to the adjoining fields through water inlets. After the invasion to the adjoining fields, they dispersed widely over the paddy fields. The maximum movement distance was 68m, although most of the snails moved less than 30m.
Salt-preserved cherry leaves are used as an indispensable material for traditional Japanese sweets. The leaves are harvested from cherry trees (Prunus lannesiana var. speciosa) grown mainly in Southern Izu Peninsula, central Japan, where cherry tree growing is one of the most important industries. Until today there have been few reports on the pest insects infesting these cherry trees. The author surveyed the pest insect fauna on the cherry trees, resulting in 50 species including two spider mite species. It was clarified that peculiar elongated holes on the cherry leaves were caused by feeding behavior of Frankliniella intonsa (Trybom) (Thysanoptera Thripidae) before leaf unfolding.
The susceptibility of 19 insecticides to spider mite predators was examined with the second or third-instar larvae of Stethorus japonicus H. Kamiya by using a direct spraying test. Chlorfenapyr and Ethiprole were determined to be harmless and two neonicotinoids (Nitenpyram and Dinotefuran) were determined to be slightly harmful. The use of these insecticides should be recommended in IPM programs to control insect pests in citrus orchards.