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On the Bionomical Notes of Tea Root Parasitic Nematodes, Hemicriconemoides Kanayaensis and Others, in Makinohara Tea Plantation at Shizuoka-Ken

1964; Japan Epidemiological Association; Volume: 1964; Issue: 21 Linguagem: Inglês

10.5979/cha.1964.41

1883-941X

Takeshi Kaneko,

Nematode management and characterization studies

1. The observations and experiments on the bionomics of tea parasitic nematodes, especially Hemicriconemoides, were carried out at Makinohara tea plantation, Shizuoka, one of the biggest tea growing areas in Japan.The population of Hemicriconemoides in the soil was very high. The nematode is the most serious pest of tea roots, and has been probably scattered with root soils of the tea cutting nurseries of variety Yabukita from infested tea garden to new garden.Pratylenchus was the most wide spread nematode pest of tea roots in the mature tea garden of the domestic varieties.2. The populations of nematode in the soil were surveyed. A large majority of Hemicriconemoides and Paratylenchus were found in comparatively deep place (about 30cm. depth), whereas Pratylenchus and Helicotylenchus mostly in the upper layer of the soil (about 10cm. depth).Especially, the maximum number of Hemicriconemoides occurred at a depth of 30-40cm., where heavily infested rootlets accumulated as horse dung appearance in the clay layers.3. Hemicriconemoides is ectoparasitic and attacks mainly the rootlets of tea plant. Pratylenchus is endoparasitic and usually attacks both the main roots and the rootlets.Hemicriconemoides around tea root was examined and recorded in drawings.4. The seasonal fluctuation of the population of Hemicriconemoides was examined by the Baermann funnel technique. The egg laying occurred in May and November, in the former month it is in greater rate ; and the fluctuation of the male population coincided with the egg laying period. The larval growth occurred in the latter half of the year, from May to November, and the maximum rate occurred in July.Adult females occupied most portion of the population, i. e., the ratio of adult female in total individuals ranged from 97% the highest in January to 64% the lowest in July, and adult males were only found in 0.6% of the total.Single female contained usually 14-15 (maximum is 16) eggs and egg cells and laid eggs one by one. According to the observation in the laboratory, egg laying period of a female adult was 7 days in June and July, and 20-23 days in November; and the period from egg laying to hatching was 15-20 days in June and July, and 35-40 days in November.The life cycle of Hemicriconemoides may be required about 100 days.5. The population of nematode was studied at the tea garden where the double amount of the nitrogenous manuring standard was supplied. It seemed that the population of Hemicriconemoides was lowered by the excessive supply of the fertilizer, while the reverse was the case with Paratylenchus.6. A species of soil fungus was commonly found attacking adult Hemicriconemoides in the laboratory conditions.