Many field experiments have revealed sugarcane yield loss due to plant-parasitic nematodes, especially in sandy soil, but limited in clay soil. We previously reported a 15% sugarcane yield reduction in the plant crop in a heavy clay soil due to lesion nematodes suppressing the number of sugarcane tillers in the early growth stage (Kawanobe et al., 2016). Yet, it is unknown whether such early growth inhibition in plant canes will affect the ratoon crop yield in clay soil. The objective of this study was to examine the carry-over effect of yield decline from the plant crop to the ratoon crop in a field with high clay content (> 80%), in which early growth inhibition, possibly due to lesion nematodes, was observed in a plant crop of sugarcane. Though the Pratylenchus population density remained unchanged among treatments (fosthiazate-treated, 3 kg and 7.5 kg/ha at spring planting, and non-treated control), after 5 months (July) from the spring planting until the harvest of the ratoon crop, our study showed a 20–25% higher yield of the ratoon crop in the fosthiazate-treated crop than in the non-treated control. The result in the plant crop carried over to the ratoon crop, and implied that the healthier root growth of the plant canes achieved by a one-time nematicide application would carry-over to the ratoon crop. The result also suggested that the number of tillers and cane length observed at 5 months (July) in the ratoon crop might adequately reflect nematode damage and offer a good explanation for the level of the ratoon crop yield.

A red-crowned crane, Grus japonensis, chick died on August 6, 2013, in Kushiro, Hokkaido, Japan. In the postmortem examination, 20 individual nematodes were found in the nasal cavity and anterior thoracic air sacs. The chick died from severe inflammation of the air sacs, granulomatous pneumonia, and esophageal strangulation, caused by a heavy nematode infection. The nematodes were identified as Cyathostoma (Hovorkonema) sp., based on their measurements and morphological characteristics. This is the first host record of these nematodes from G. japonensis and the first geographical record from Japan. Considering the life cycle, the chick was infected with the nematodes by ingestion of earthworms, because the chick had been given many earthworms as food from the parents.

Root-knot nematodes (RKN) are one of the most economically damaging nematodes in Japan as well as in the world. In November 2014, we found malformed taro (Colocasia esculenta) tubers in the field. Many RKN second juveniles were extracted from soil by the Baermann funnel method and female adults were found parasitizing on the tubers. Nematode species was identified with PCR-RFLP method using individual nematodes, and all RKN specimens were identified as Meloidogyne microcephala (Mm). We also identified RKN from the soil of several fields where taro’s seeds cultivated in the previous year (Field 2), tomato greenhouse and green pepper greenhouses neighboring to Field 2 (Field 3 and 4, respectively) and tomato greenhouse about 300 m apart from Field 2 (Field 5). The number of RKN (Meloidogyne incognita (Mi) / Mm) of Field 2, 3, 4 and 5 were 18/11, 15/23, 30/0 and 8/0, respectively.