Although nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used for musculoskeletal pain, their use in patients with heart failure (HF) is discouraged because of risks of fluid retention and worsening disease. Nevertheless, in older patients, NSAIDs are still prescribed by non-cardiologists. We conducted a single-center retrospective cohort study of patients aged ≥ 65 years who were hospitalized for acute decompensated HF at Yamaguchi Prefectural General Medical Center between January 2016 and January 2022. Patients were classified as NSAIDs-related HF if NSAIDs use for ≥ 1 week before admission was identified through pharmacist review. As part of comprehensive cardiac rehabilitation, all patients received self-management guidance on medications, including NSAIDs avoidance. Multivariate Cox proportional hazards models were applied to assess associations with clinical outcomes. Among 801 patients, 64 (8.0%) were classified as NSAIDs-related HF and 737 (92.0%) as NSAIDs-unrelated HF. NSAIDs-related HF cases more frequently represented first-time HF hospitalizations. For the primary endpoint of all-cause mortality or HF readmission, the NSAIDs-related group showed a trend toward improved outcomes, although the difference did not reach statistical significance (hazard ratio [HR] 0.569, 95% confidence interval [CI] 0.289-1.118; p = 0.102). In contrast, the incidence of the secondary endpoint, major adverse cardiac and cerebrovascular events (MACCE), was significantly lower in the NSAIDs-related group (HR 0.404, CI 0.178-0.917; p = 0.030). NSAIDs-related HF accounted for a modest proportion of new HF hospitalizations in older patients. After standard management and NSAIDs discontinuation, outcomes were comparable to those of other HF patients, with a trend toward fewer adverse events. These findings likely reflect differences in patient background and comprehensive rehabilitation rather than a direct protective effect of discontinuation.

To clarify the effect of ambient temperature on the abundance of the two pecky rice bug species Niphe elongata and Cletus punctiger in organic rice paddy fields, we studied the relationships between the abundance of these species and temperatures recorded from November to April in Yamaguchi Prefecture, Japan, in 2022 and 2023. The periods during which temperature affected the abundance of both species were determined. Our analyses revealed that the abundance of N. elongata was significantly and positively related to the average minimum temperature in mid-April, suggesting that the low temperatures after the diapause termination may be associated with N. elongata mortality. The abundance of C. punctiger was significantly and positively related to the average maximum temperature in mid-March, suggesting that the higher temperature soon after the diapause termination makes it possible for overwintered C. punctiger adults to feed on host plants from earlier in the season. The heading period of rice was also observed to affect both species’ abundance in paddy fields. These results may allow us to estimate the abundance of both species based on the temperature before the start of rice cultivation and the rice heading period.

Kudoa septempunctata, a parasite found in olive flounder, poses a growing food safety risk in East Asia, particularly in Japan and South Korea. K. septempunctata poisoning caused by raw fish consumption causes brief gastrointestinal symptoms. However, long-term, national-scale aggregated epidemiological data for K. septempunctata food poisoning are limited. In this retrospective study, we examined the recent epidemiological trends and characteristics of K. septempunctata food poisoning cases reported in Japan between January 2013 and December 2023. Ministry of Health "Foodborne Illness Statistical Data" were assessed for case counts, outbreaks, and implicated foods. Reported cases totaled 2009, reaching a peak in 2014 (429 cases) then declining to < 100 cases during the COVID-19 pandemic. October had the highest number of monthly reports. Flounder, particularly sashimi and sushi, were implicated in 99% of cases. The highest case counts occurred in Yamaguchi, Osaka, and Fukuoka prefectures (160, 155, and 154, respectively). Tottori, Shimane, Yamaguchi and Oita prefectures had the highest incidence rates (14.3, 10.9, 10.7, and 10.7 per 1,000,000 population, respectively). Prefectures along the Sea of Japan typically reported higher incidence rates. This study highlights the importance of continued surveillance and reporting of K. septempunctata poisoning, and the need to consider Kudoa infections in the differential diagnosis of food poisoning cases involving raw fish consumption.

Lions and tigers, as dominant apex predators, likely became competitors when lions expanded from Africa into Eurasia approximately one million years ago (Ma), forming a lion-tiger transition belt from the Middle East through Central Asia to the Russian Far East. At the easternmost edge of this zone, the Japanese Archipelago has long been considered a Late Pleistocene tiger refugium, supported by large felid subfossils traditionally attributed to tigers (Panthera tigris), though their taxonomic identity remained unresolved. To clarify the origin, evolutionary history, and biogeography of Japan's Pleistocene felids, we analyzed 26 ancient specimens previously assumed to be tigers. Using mitochondrial and nuclear genome hybridization capture and sequencing, paleoproteomics, Bayesian molecular dating, and radiocarbon dating, we found that all ancient Japanese "tiger" remains yielding molecular data were, unexpectedly, cave lions (Panthera spelaea). One specimen from Yamaguchi Prefecture, western Japan, was radiocarbon dated to 36,000-34,891 cal. BP. These cave lions likely dispersed to the Japanese Archipelago between ~72.7 and 37.5 thousand years ago (ka), when a land bridge connected northern Japan to the mainland during the Last Glacial Period. Our findings challenge the long-held view that tigers once took refuge in Japan, showing instead that cave lions were widespread in northeast Asia during this period and were the Panthera lineage that colonized Japan, reaching even its southwestern regions despite habitats previously thought to favor tigers.

BackgroundKudoa septempunctata, a parasite found in olive flounder, poses a growing food safety risk in East Asia, particularly Japan and South Korea. Linked to raw fish consumption, K. septempunctata poisoning causes brief gastrointestinal symptoms. This study aimed to characterize recent epidemiological trends and characteristics of K. septempunctata food poisoning by using national data from Japan.MethodsThis retrospective study examined Kudoa food poisoning cases reported in Japan between January 2013 and December 2023. Data from the Ministry of Health’s “Foodborne Illness Statistical Data” report were assessed for case counts, outbreaks, and implicated foods.ResultsA total of 2,009 cases were reported, peaking in 2014 (429 cases) and declining to < 100 cases since 2020. October had the highest number of monthly reports. The age distribution showed that the majority of cases occurred among older adults, with individuals aged 60–69 years (23.5%) and those 70 years and older (26.0%) together accounting for nearly half of all cases. Cases among individuals younger than 20 years comprised less than 2.5% of all cases. Flounder, particularly sashimi and sushi, were implicated in 99% of cases. The highest case counts occurred in Yamaguchi, Osaka, and Fukuoka prefectures (160, 155, and 154, respectively). Tottori, Shimane, Yamaguchi and Oita prefectures had the highest incidence rates (14.3, 10.9, 10.7, and 10.7 per 1,000,000 population, respectively). Prefectures along the Sea of Japan tended to report higher incidence rates.Conclusionhis is the first study to describe Kudoa food poisoning in Japan. Clinicians should consider Kudoa infections in cases of food poisoning involving raw fish.DisclosuresAll Authors: No reported disclosures

Zircon U-Pb dating was conducted on granite, granodiorite, and gabbro from the central part of Yamaguchi Prefecture, Southwest Japan.The granodiorite and gabbro are recognized as components of the Susuma-Nagaho Plutonic Complex (SNPC).The zircon U-Pb dating yielded ages of 103 Ma for the granite and 92 Ma for the granodiorite and gabbro.These ages coincide with the magmatic flare-up event documented in Southwest Japan.A compiled dataset of Cretaceous gabbro-diorite from Southwest Japan shows that initial-Nd values (NdI) decrease progressively to as low as -5.1 between 107 Ma and 90 Ma.In addition, Th/La ratios exhibit a negative correlation with initial-Nd isotopic ratios.These geochemical trends, together with their temporal variation, suggest that subducted sediments increasingly interacted with the mantle wedge, producing progressively enriched mantle sources throughout the Cretaceous.This secular change may reflect variations in plate motion, such as change in the rate of subduction.

BackgroundOur Neurosurgery Department started inter-hospital medical collaboration using hotline telephones in 2000 and has been sharing images using videophone and smartphones since 2002. Currently, an image sharing system using Synapse (Fujifilm medical) is deployed at 15 hospitals in and outside of Yamaguchi Prefecture, and about 300 Doctor to Doctor (D2D) consultations are conducted annually. The consultations conducted so far have been D2D telephone consultations for acute diseases, mainly stroke and head trauma.ProblemWhile it is difficult to maintain advanced medical care of brain tumor in depopulated areas, a system is needed to enable consultation on treatment plans and advanced medical care at hospitals in depopulated areas in order to minimize the burden of patient travel. To achieve this, a system that (1) enables easy communication, (2) makes images available to all hospitals, and (3) is low-cost is needed.MethodsTo solve these problems, we established MEDIMONY, the first start-up company from our department, and have been developing the system. The system is based on a zero-touch system that allows hospitals in underpopulated areas to communicate with each other without having to operate the system. The zero-touch system is operated with ordinary tablets and uses LTE for communication, so Wi-Fi is not required for hospitals in depopulated areas. Doctor to Patient (D2P) with D has been in operation since May 2025, using this system to provide chemotherapy at hospitals in underpopulated areas.FutureThe company is also developing a system to share monitor images from electronic medical records without the need for an image sharing system, aiming to enable consultations at all hospitals. The company will continue to develop D2D and D2P with D for brain tumor patients in Yamaguchi Prefecture, aiming to create a model project that will enable equalization of medical care in depopulated areas.

Objective We broadly assessed how open residents in rural and remote areas are to using telemedicine, and whether an association exists between openness to telemedicine use and resident demographics including clinical visit status and advance care planning. Methods A self-administered survey was disseminated via mail between October 2022 and January 2023. Participants included 3,767 residents of nine districts with remote and rural medical care services in Shunan City, Yamaguchi Prefecture aged ≥20 years. We selected participants using stratified random sampling by district, sex, and age. The survey comprised questions regarding willingness to use telemedicine services including online medical care and medication counseling, resident characteristics, clinical visit status, and willingness to accept long-term and terminal care. Multivariate logistic regression analysis was used to assess potential factors associated with willingness or unwillingness to use telemedicine. We also analyzed the specific reasons given in the responses of those who did not want to use telemedicine.Results A total of 1,540 respondents were included in the final analyses (valid response rate: 40.9%). Regarding telemedicine use, 43.0% and 48.1% of respondents were willing to use online medical care in their family clinics and in their own houses, respectively. Additionally, 53.5% expressed a desire to use medication counseling clinics. Willingness to use telemedicine associated significantly with smartphone users and responders aged ≤50 years of age. Notably, hospital visitors and remote island residents were unwilling to use online medical care services. Time required to visit a hospital/clinic, residents living alone, and resident's desire to receive terminal care at home did not correlate significantly. The most common reasons given by those who did not want to use telemedicine were "easier to talk to someone in person (45.2-56.0%)," "never experienced it before (36.6-41.2%)," and "difficult to hear explanations (12.5-14.3%)." Other reasons (free responses) included "Don't know/don't need it (27.8-42.4%), "No problem with current hospital visit/pharmacy care (13.6-21.5%)," and "Concerns regarding equipment operation (10.4-18.2%).Conclusions We identified factors associated with positive and negative attitudes toward telemedicine among residents of rural and remote areas. Our findings underscore the importance of promoting residents' understanding of the convenience and necessity of telemedicine by increasing their opportunities to experience it.

The number of drowning deaths worldwide is increasing, and preventive measures are being developed on a global scale. However, unlike the global trend, elderly people account for most drowning deaths in Japan, which suggests that unique surveys and measures are required. In this study, we analyzed forensic autopsy cases of river drowning in a part of Japan to reveal the characteristics of the deaths and of finding of the deceased. We retrospectively investigated river drowning cases for which a forensic autopsy was performed from 2012 to 2021 in Yamaguchi Prefecture, Japan. Various factors were examined statistically for comparison of accidents and suicides. The accident group tended to be older and many had cognitive impairments or reduced mobility, while the suicide group tended to be younger, with a higher proportion in their 50s and 60s. Many cases in both groups occurred within 6h of the last confirmed contact. The suicide cases were reported as missing more frequently than the accident cases. The accident cases tended to occur in smaller, more familiar rivers, while suicide cases tended to occur in larger rivers further from home. Preventive measures such as guardrails or fences were present in 81.8% of the suicide cases and 22.0% of the accident cases. This study highlights the importance of timely searches, innovative preventive measures, and societal awareness focused on people with mental and cognitive problems to address the underlying factors contributing to drowning in rivers due to accident and suicide in Japan.

Non-immunoglobulin E-mediated gastrointestinal food allergies (non-IgE-GI-FAs) in children with Down syndrome (DS) tend to be more severe, with some children presenting with sepsis-like symptoms. However, the epidemiology of this condition remains unknown. This study aimed to investigate the prevalence rate and clinical characteristics of non-IgE-GI-FAs in children with DS. This study included 115 children with non-IgE-GI-FAs diagnosed at 13 hospitals in Yamaguchi Prefecture, Japan, between January 1, 2011, and December 31, 2020. The children were classified into DS and non-DS groups, and their clinical characteristics were retrospectively compared. Among the 115 children with non-IgE-GI-FAs, 7 and 108 were included in the DS and non-DS groups, respectively. During the study period, 184 children with DS were born in Yamaguchi prefecture, and 7 developed non-IgE-GI-FAs. In this study, the prevalence rate of non-IgE-GI-FAs was 3.8% (7/184) in children with DS and 0.11% (108/98,989) in children without DS. No significant differences were observed in causative foods, age at onset, age at diagnosis, or age at confirmed clinical remission between the 2 groups. Most children in both groups experienced vomiting and diarrhea, but none had hypothermia. Sepsis-like symptoms, such as lethargy (71.4% vs. 24.1%, P = 0.0150), hypotension (42.9% vs. 0.9%, P = 0.0006), and fever (57.1% and 8.3%, P = 0.0030), were significantly more common in the DS group than in the non-DS group. The prevalence rate of non-IgE-GI-FAs was 3.8% in children with DS and 0.11% in children without DS. Non-IgE-GI-FAs in children with DS were significantly more severe than those in children without DS. Non-IgE-GI-FAs should be considered a differential diagnosis when sepsis-like symptoms are observed in children with DS.

Genetic diversity of pathogenic Leptospira spp. harbored by bats in Japan.

Research into the supply of tourism accommodations in rural areas is essential, given tourism's central role in rural revitalisation. Recent studies increasingly employ Geographical Information Systems (GIS) to analyse the distribution and determinants of rural accommodations. However, a significant gap remains in the literature addressing rural Japan specifically. This study investigates the spatial distribution and pricing dynamics of Nohaku accommodations in Yamaguchi Prefecture, Japan. A comprehensive database was compiled from multiple sources to document accommodations and their respective prices across Japanese prefectures. The analysis integrates spatial analysis and the Spatial Durbin Model (SDM) to assess spatial clustering and the determinants of accommodation pricing. Results reveal significant clustering of Nohaku accommodations around key tourism resources and identify regions with untapped tourism potential. Spatial econometric analysis shows that Nohaku accommodations command a price premium, and proximity to tourism resources positively affects pricing. The results offer a nuanced understanding of spatial patterns and pricing strategies, providing actionable insights for policymakers to optimise rural tourism development.

ABSTRACT This article discusses the significance of whaling heritage in contemporary Japan. It distinguishes between whaling as lived socioeconomic practice on the one hand, and whaling heritage as social imaginary that is central to the construction of collective identities on the other. Its argument is twofold. First, it argues that heritage-making is not just a matter of nostalgia or care for history but fundamentally a future-oriented endeavour, and that conceptions of heritage are key components of social imaginaries today. Second, it argues that whaling heritage can be preserved and recreated as a set of cultural practices and resources for tourism and identity construction irrespective of the survival of the whaling industry. The article discusses three examples of whaling heritage that have gained new significance in recent years as markers of local identity, tourist attractions, and symbols of community cohesion: the cultivation and promotion of early modern whaling heritage in the whaling town of Taiji (Wakayama Prefecture), the meanings attributed to a re-enactment event and festival in the former whaling town of Kayoi (Yamaguchi Prefecture), and the changing significance of a similar but older festival in the non-whaling town of Yokkaichi (Mie Prefecture). None of these practices is contingent upon whaling per se. All of these cases constitute creative attempts to draw upon histories of whaling and other human-whale relations to shape new meanings, notions of belonging, and livelihoods today.

Although comprehensive cardiac rehabilitation (CR) is an effective treatment for cardiovascular diseases, its implementation in Japan remains insufficient. Following the 2022 Basic Act on Cardiovascular Disease Prevention, each prefecture has established specific targets. We report our experience implementing and managing CR programs across hospitals of different sizes in Yamaguchi Prefecture, Japan, including Tokuyama Medical Association Hospital (initiated in 2019), Mitajiri Hospital (initiated in 2022), and Yamaguchi Prefectural Grand Medical Center. Hospital size and functionality correlated with the diversity and number of healthcare professionals available to provide CR services. In mixed-care hospitals, both inpatient and outpatient CR participants were older compared with acute-care hospitals. Insurance reimbursement calculations and bed-type restrictions affected CR service delivery. The CR team exemplifies interprofessional collaboration in cardiovascular care. Even without all the necessary professional roles, patients can benefit significantly from CR implemented using available resources. Building effective organizations requires embracing diversity and enabling each profession to demonstrate its expertise while ensuring the psychological safety of team members.

Hepatitis E virus (HEV) is a zoonotic pathogen with multiple hosts, posing significant public health risks, especially in regions like Japan where game meat consumption is prevalent. This study investigated HEV infection and viral shedding in wild boars, sika deer, and Japanese serows across Japan. A total of 1896 serum samples were tested for anti-HEV antibodies, 1034 for HEV RNA, and 473 fecal samples for viral shedding. Anti-HEV antibodies were detected in wild boars from all seven prefectures studied, while HEV RNA was detected in wild boars from Fukuoka, Oita, and Miyazaki in southern Japan, as well as Yamaguchi prefecture. Genetic analysis revealed subtypes 3b, 4a, and 4g, with 3b being the most prevalent. Subtype 3b exhibited distinct geographical clustering, whereas 4g persisted exclusively in Yamaguchi for over 12 years. Infectious HEV particles were confirmed in wild boar feces, highlighting the risk of environmental contamination and zoonotic transmission. Sika deer showed no evidence of HEV infection, and only one Japanese serow tested positive for antibodies without detectable RNA. These findings underscore the importance of ongoing surveillance to assess the zoonotic risks from game meat consumption and prevention of HEV transmission to humans.

Background: The dark green coloration of bunching onion leaf blades is a key determinant of market value, nutritional quality, and visual appeal. This trait is regulated by a complex network of pigment interactions, which not only determine coloration but also serve as critical indicators of plant growth dynamics and stress responses. This study aimed to elucidate the mechanisms regulating the dark green trait and develop a predictive model for accurately assessing pigment composition. These advancements enable the efficient selection of dark green varieties and facilitate the establishment of optimal growth environments through plant growth monitoring. Methods: Seven varieties and lines of heat-tolerant bunching onions were analyzed, including two commercial F1 cultivars, along with two purebred varieties and three F1 hybrid lines bred in Yamaguchi Prefecture. The analysis was conducted on visible spectral reflectance data (400-700 nm at 20 nm intervals) and pigment compounds (chlorophyll a, chlorophyll b and pheophytin a, lutein, and β-carotene), whereas primary and secondary metabolites were assessed by using widely targeted metabolomics. In addition, a random forest regression model was constructed by using spectral reflectance data and pigment compound contents. Results: Principal component analysis based on spectral reflectance data and the comparative profiling of 186 metabolites revealed characteristic metabolite accumulation associated with each green color pattern. The "green" group showed greater accumulation of sugars, the "gray green" group was characterized by the accumulation of phenolic compounds, and the "dark green" group exhibited accumulation of cyanidins. These metabolites are suggested to accumulate in response to environmental stress, and these differences are likely to influence green coloration traits. Furthermore, among the regression models for estimating pigment compound contents, the one for chlorophyll a content achieved high accuracy, with an R2 value of 0.88 in the test dataset and 0.78 in Leave-One-Out Cross-Validation, demonstrating its potential for practical application in trait evaluation. However, since the regression model developed in this study is based on data obtained from greenhouse conditions, it is necessary to incorporate field trial results and reconstruct the model to enhance its adaptability. Conclusions: This study revealed that cyanidin is involved in the characteristics of dark green varieties. Additionally, it was demonstrated that chlorophyll a can be predicted using visible spectral reflectance. These findings suggest the potential for developing markers for the dark green trait, selecting high-pigment-accumulating varieties, and facilitating the simple real-time diagnosis of plant growth conditions and stress status, thereby enabling the establishment of optimal environmental conditions. Future studies will aim to elucidate the genetic factors regulating pigment accumulation, facilitating the breeding of dark green varieties with enhanced coloration traits for summer cultivation.

This study aimed to conduct a comparative epidemiological survey of uveitis across various healthcare settings and elucidate the clinical characteristics. We conducted a retrospective cross-sectional study in the Ube-City medical region in Yamaguchi prefecture and recruited 268 patients from a university hospital (151 patients), municipal hospitals (51 patients), and private eye clinics (58 patients). Medical records of patients newly diagnosed with uveitis between January 2018 and December 2019 in the institutes were included, reviewed, and compared. The main outcomes included the number of uveitis causes, treatment methods, and visual acuity. Panuveitis, which is associated with systemic diseases, such as Vogt–Koyanagi–Harada disease and sarcoidosis, was more prominent in university hospital patients. Conversely, anterior uveitis, including traumatic iritis, was prominently detected in general hospitals and private eye clinics. The best-corrected visual acuity improved to 1.0 (logMAR = 0); an improvement of 74%, 61%, and 54% was observed in private eye clinic, general hospital, and university hospital patients, respectively. This study identified differences in uveitis presentation and treatment across diverse clinical settings. The results of this study provide valuable data for differentiating the causes of uveitis at university hospitals, general hospitals, and private eye clinics.

• Forest insurance claim payments were used as an indicator of drought damage. • Factors affecting drought damage of young planted forests were analyzed using GIS. • Site conditions vulnerable to drought differed between regions and species. • Clayey soil was the drought risk factor in Kamikawa, but not in Yamaguchi region. • High risk at terraces with clay soil was found only for Japanese larch in Kamikawa. Due to the increasing frequency of extreme weather events, drought damage to trees threatens forestry production and forest ecosystems worldwide. Assessing the site conditions under which trees are vulnerable to drought damage provides key information for the establishment of countermeasures to prevent such damage. This study aimed to clarify the differences in drought vulnerability of young planted forests between regions and species by using forest insurance claims from all over Japan as a damage indicator. We targeted the two most damaged species in two of the most drought-affected regions from 2016 to 2021. Although landform and soil type were found to be influential factors in the Kamikawa Subprefecture of Hokkaido, these factors did not affect the drought damage in Yamaguchi Prefecture. In Kamikawa, the drought damage risk was high for Larix kaempferi on river terraces and for Abies sachalinensis on mountain areas with compacted brown forest soil. Clayey soil, which can prevent plants from absorbing water, has been known to distribute on the terraces and the mountains with compacted soil in Kamikawa. Therefore, our analysis identified clayey soil as a cause of drought vulnerability in Kamikawa. In addition, L. kaempferi was suggested to be especially vulnerable on flat terraces with less permeable clayey soil due to root damage associated with excessive soil moisture before drought. This study demonstrated that forest insurance can be used not only for damage compensation, but also as a source of information for identifying region- and species-specific risk factors for meteorological damage in forests.

Abstract In 1967, at the beginning of the Cultural Revolution, the Hagurumaza Troupe from Yamaguchi Prefecture, Japan, was invited to perform their dramas Nobi (Prairie Fire) and Arashi mo fubuki mo don to koi (Marching Against the Storm) in China. The troupe was received by Mao Zedong and became recognized as a “revolutionary cultural warrior” approved by China. They returned to Japan and propagated Mao Zedong Thought through dramas, leaving their mark across the country. On the one hand, the case of the troupe demonstrates the active spread of Mao Zedong Thought in Japan, while on the other hand, it reveals the Japanese people’s resistance to it. This paper focuses on the drama Nobi and draws on a variety of Chinese and Japanese historical documents to discuss the troupe’s process of becoming a revolutionary cultural warrior and its propaganda activities in Japan. The paper also analyzes the dilemma of having to cater to China while also pleasing the Japanese and highlights the conditions and difficulties of spreading Mao Zedong Thought in Japan.

山口県よりも冷涼な地域において雑草イネ防除に有効とされている秋期の不耕起と除草剤の体系処理が山口県においても有効であるか検証した。雑草イネ種子を地表面で越冬させた場合，土中で越冬させた場合と比べて越冬後の出芽率は高い場合が多く，秋期の不耕起が雑草イネの防除に有効とはいえなかった。除草剤の検証では，初中期一発剤と中期剤の体系処理であっても，5月下旬の水稲移植栽培では代かきから初中期一発剤処理前に出芽したと考えられる雑草イネが残草する場合があった。このことから，除草剤の体系処理では代かきから1剤目の処理の間隔を可能な限り短くすることが重要と考えられた。