Stem and root rot of rocket, Eruca sativa Mill., and leaf blight of oregano, Oreganum vulgare L., occurred in Tokyo Metropolis in 2005. Rhizoctonia species isolated from the infected plants were identified as Rhizoctonia solani Kühn. Inoculation tests showed that these fungi were the causal agents of these diseases. This is the first report on these diseases in Japan.
Sclerotinia rot of komatsuna, a leafy variety of Brassica campestris L., occurred in Tokyo Metropolis in 2003. The causal fungus isolated from the diseased plants was identified as Sclerotinia sclerotiorum (Libert) de Bary. Inoculation tests showed that this fungus was the causal agent of this disease. This is the first report on the disease in Japan.
Anthracnose of Phormium tenax J. R. Forst. & G. Forst. and Chimonanthus praecox (L) Link f. concolor occurred in Tokyo Metropolis in 2004-2005. The causal fungi isolated from the diseased plants were identified as Colletotrichum gloeosporioides (Penzig) Penzig & Saccardo. Inoculation tests showed that these fungi were the causal agents of these diseases. This is the first report on the diseases in Japan.
Gray mold and leaf blight of true lavender, Lavandula augustifolia (L.) Mill., and stevia, Stevia rebaudiana Bertoni M., occurred in Tokyo Metropolis in 2005. The fungi isolated from the infected plants with gray mold were identified as Botrytis cinerea Persoon: Fries. Inoculation tests showed that these fungi were causal agents of the diseases. This is the first report of gray mold on these plants in Japan.
We examined the effects of diet on the developmental period of nymphs, body length of adults, and emergence rate in the rice bug, Leptocorisa chinensis. The spikelets of rice, Oryza sativa, and the seeds of Italian millet, Setaria italica, were used as the diets. All growth parameters examined were improved when the insects were reared with the rice spikelets and the seeds of Italian millet together compared to that with only one of the two diets. The study indicates that the dietary condition must be reconsidered for the improvement of accuracy in the estimation of voltinism and generation time in this species.
The relationship between the number of pesticide spray applications and the ratio of undamaged soybean was investigated from 2002 to 2003 in a soybean field at Shintone-cho, Ibaraki Prefecture. Stinkbug density and the ratio of undamaged soybean were negatively correlated with the number of pesticide spray applications. Damage to soybean varied among the years and experimental blocks. In order to harvest 85% and 90% undamaged soybean, the insecticide needed to be sprayed for one and two times, respectively. These results imply that the number of pesticide spray applications can be reduced from three times to two times in soybean production at Shintone-cho.
Vertical distribution of the white peach scale, Pseudaulacaspis pentagona (Targioni), on tea plants was investigated, and the relationship between the elimination rate of the scale by pruning and depth of pruning were estimated on the basis of the distribution data. The most abundant number of the scales on a tea plant was found at a position a little above the mid part of the tea bush, and there were few scales on young branches in the stratum of leaves and around the lower part of plants. The elimination rate of the scales by pruning increased with depth of pruning from the top of a bush. When 70%, 60% and 50% of branches from the top of a bush were pruned, it was suggested that elimination rates were 80%, 70% and 60%, respectively.