{"created":"2023-05-15T13:37:51.465737+00:00","id":1569,"links":{},"metadata":{"_buckets":{"deposit":"84052030-07f7-4c83-a98f-b3a1790439fe"},"_deposit":{"created_by":12,"id":"1569","owners":[12],"pid":{"revision_id":0,"type":"depid","value":"1569"},"status":"published"},"_oai":{"id":"oai:repository.naro.go.jp:00001569","sets":["87:599:601:127:203"]},"author_link":["2036"],"item_10002_biblio_info_7":{"attribute_name":"書誌情報","attribute_value_mlt":[{"bibliographicIssueDates":{"bibliographicIssueDate":"2007-02-19","bibliographicIssueDateType":"Issued"},"bibliographicPageEnd":"74","bibliographicPageStart":"17","bibliographicVolumeNumber":"9","bibliographic_titles":[{"bibliographic_title":"中央農業総合研究センター研究報告"},{"bibliographic_title":"Bulletin of the National Agricultural Research Center","bibliographic_titleLang":"en"}]}]},"item_10002_description_5":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"Rice bugs are considered to be important pests of rice in Japan. When rice bugs infest a spikelet, brown or black marks appear on the grain. These stained grains are called pecky grain. Hulled rice grains that contain over 0.1% of pecky grains have reduced commercial value according to Japanese rice quality regulations. Leptocorisa chinensis Dallas is a major rice bug species in central and western regions of Japan. Recently, the prevalence occurrences and distribution area of this species have been increasing. Furthermore, there have been increases in the number of areas where the severity of pecky grain contamination damage has intensified compared to previous records. In this study, to clarify the reasons for the recent high prevalence of L. chinensis and methods to forecast pecky rice contamination damage, 1) Population dynamics and mortality factors of L. chinensis and 2) Feeding characteristics of rice bugs and modeling of the relationship between the density of L. chinensis and the probability of damage occurrence were investigated. The results obtained in each chapter are summarized as follows. 1. Population dynamics and mortality factors of L. chinensis 1) Overwintering adults of L. chinensis appeared in grass fields in southern Ibaraki Prefecture from late June to early July. Their progeny appeared soon after, and the subsequent population fluctuation was bimodal. In contrast, overwintering adults of Cletus punctiger appeared much earlier, in early May, while the next-generation nymphs were seldom observed until late June. Based on the immigration dates of overwintering adults and the cumulative effective temperature for development and ovarian maturation, it was confirmed that L. chinensis is bivoltine in the study area. Peak occurrence of L. chinensis adults in grass fields did not coincide with the heading date of mid-season rice cultivated most widely in southern Ibaraki Prefecture. This reveals that current rice cultivation practices in this area are suitable to prevent the massive invasion of L. chinensis. 2) Using cages set in rice fields, the relationship between the number of L. chinensis and the number of pecky rice grains were investigated. Eggs of L. chinensis were released, in number ranging from 6 to 36, into 1.6× 1.6×1.5m cages at the milk ripening stage in a rice field. The number of pecky grains was highly correlated with the number of hatched nymphs and the number of individuals (both of adults and nymphs) at harvest, but not with the number of eggs released. Furthermore, the number of hatched nymphs was highly correlated with the number of individuals at harvest, but not with the number of eggs released. The egg survival rate was bimodal, with peaks at 0-20 or 80-100%, suggesting that predators caused an all-or-nothing type mortality to the eggs masses. These results indicate that an estimation of the density of hatched nymphs is more important than those of immigrant adults for obtaining a highly accurate estimation of pecky rice damage in rice fields. 3) To clarify factors causing mortality of L. chinensis eggs, sentinel egg masses were exposed at intervals of four days in two gramineous weed areas, a rice field, and a soybean field, from July to September. Parasitized eggs occurred in the retrieved sentinel egg masses in the four areas. The peak parasitized egg ratio was 30%, 70% in the each of the two gramineous weed areas, respectively, 9% in the rice field, and 42% in the soybean field. Some missing eggs also occurred in the four areas. The peak missing egg ratios were 56%, 73%, 50%, and 67%, respectively. These findings indicate that Gryon japonicum and egg predators are major mortality factors of L. chinensis eggs. 4) Trial sentinel eggs, application of insecticides, and field censuses were employed to clarify the species of L chinensis egg predators in the two rice fields that had been transplanted on 23 April (Field B) and 10 May (Field A). The average numbers of hatched and missing eggs did not differ significantly between the sprayed and control plots in field A. In field B, however, the numbers were significantly different. The percentage of missing eggs in damaged egg masses ranged from 80-100%. In the laboratory, we found that the feeding marks caused by the meadow grasshopper, Conocephalus chinensis, have characteristics that are similar to those on the eggs exposed in the rice fields. The density of C. chinensis was low in control plots of Field A. In contrast, the density was high in those of Field B. These observations suggest that the density of egg predators, e.g. C. chinensis, was a mortality factor of L. chinensis eggs in rice fields. 2. Feeding characteristics of rice bugs and modeling of the relationship between the density of L. chinensis and the probability of damage occurrence. 1) Feeding marks on grains were investigated to clarify species specific characters. The feeding marks caused by L. chinensis and Lagynotomus elongatus were mostly found on the grain surface along the hooking portion and the basal part of the grain, respectively, while those caused by C. punctiger were found everywhere under lemma and palea. The position of the feeding marks on rice grains was species-specific, and independent of the ripening stage of the rice and the developmental stage of rice bugs. These results provide useful information for specifying the major species causing the pecky rice. 2) To clarify the ripening stages of spikelets preferentially attacked by L. chinensis, L. elongatus, C. punctiger, and Stenotus rubrovittatus in paddy fields, rice bugs were individually released for three days onto a rice panicle at various stages of maturation (7, 14, 21 and 28 days after heading, DAH). The spikelets were classified into three groups, Group A (early flowering), Group B (mid-flowering), and Group C (late flowering), according to the position in a panicle, which is closely related to the flowering order. The bugs chose to feed on the spikelets in Group A and Group B on 7 DAH. At 14 and 21 DAH, however, bugs preferred the spikelets in Group C to those in the other two groups. In L. chinensis, L. elongatus, and S. rubrovittatus, the total number of damaged spikelets decreased with maturation of the panicle, whereas there was no remarkable change in the number of spikelets damaged by C. punctiger. These results suggest that all species of rice bugs except C. punctiger selectively damage spikelets of ovaries are developing with lengthwise to sidewise elongation, whereas C. punctiger mainly attacks spikelets of ovaries developing with lengthwise to thickness elongation. 3) To clarify the relationship between the occurrence patterns of L. chinensis, L. elongatus and S. rubrovittatus and the developmental stage of panicles in rice fields, we observed the development of spikelets in three paddy fields. Spikelets were classified into three stages based on ovarian development: Stage I (initial), Stage II (middle), and Stage III (fullness). Variations in the average number of each stage of spikelet development among the three plots expressed in cumulative degree-days were smaller than those expressed in days after the initial heading stage. The peaks of adult incidence were near the peak of Stage I at 50-150 degree-days. The incidence of nymphs began to increase near the peak of Stage II at 200-250 degree-days. The occurrence patterns of all the three rice bug species were found to be closely related to the abundance of the three stages of spikelets. Cumulative degree-days can be used to uniformly express the changes in the incidence of rice bugs among different rice varieties, seasons, and fields. 4) In order to clarify the effect of split-hull paddy on the ratio of pecky rice grains caused by L. chinensis, we carried out an experiment using cages set in rice fields where two rice varieties, 'Akitakomachi' or 'Hitomebore' were transplanted. The ratio of split-hull paddy was about 5% in Akitakomachi and 1% in Hitomebore. The numbers of pecky grains per 1000 hulled grains did not differ significantly between the two varieties. These results indicate that the split-hull paddies tend to be infested by L. chinensis. However, when the split-hull ratio is less than 5%, the ratio of pecky rice grains does not show a remarkable increase. 5) To estimate the occurrence of pecky grain damage caused by L. chinensis in rice fields, I constructed 30 logistic regression models using the data obtained from field censuses. The explanatory variables of each model were: different combinations of rice variety, date of initial heading stage, number of adults at early ripening stage, and numbers of adults, nymphs and their total at the mid-ripening stage. Akaike's information criteria indicated that a model whose explanatory variable was the number of nymphs at the mid-ripening stage was statistically better than the other models. These results suggest that a census of nymphs at the mid-ripening stage, which is 200-300 day-degrees from the initial heading stage, is an appropriate way to estimate the occurrence of pecky grains\n","subitem_description_type":"Abstract"}]},"item_10002_identifier_registration":{"attribute_name":"ID登録","attribute_value_mlt":[{"subitem_identifier_reg_text":"10.24514/00001527","subitem_identifier_reg_type":"JaLC"}]},"item_10002_publisher_8":{"attribute_name":"出版者","attribute_value_mlt":[{"subitem_publisher":"独立行政法人 農業・食品産業技術総合研究機構 中央農業総合研究センター"}]},"item_10002_relation_14":{"attribute_name":"DOI","attribute_value_mlt":[{"subitem_relation_type":"isIdenticalTo","subitem_relation_type_id":{"subitem_relation_type_id_text":"10.24514/00001527","subitem_relation_type_select":"DOI"}}]},"item_10002_source_id_9":{"attribute_name":"ISSN","attribute_value_mlt":[{"subitem_source_identifier":"1881-6738","subitem_source_identifier_type":"ISSN"}]},"item_10002_version_type_20":{"attribute_name":"著者版フラグ","attribute_value_mlt":[{"subitem_version_resource":"http://purl.org/coar/version/c_970fb48d4fbd8a85","subitem_version_type":"VoR"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"竹内, 博昭"},{"creatorName":"タケウチ, ヒロアキ","creatorNameLang":"ja-Kana"},{"creatorName":"TAKEUCHI, Hiroaki","creatorNameLang":"en"}],"nameIdentifiers":[{"nameIdentifier":"2036","nameIdentifierScheme":"WEKO"},{"nameIdentifier":"50370507","nameIdentifierScheme":"e-Rad","nameIdentifierURI":"https://kaken.nii.ac.jp/ja/search/?qm=50370507"},{"nameIdentifier":"read0004211","nameIdentifierScheme":"researchmap","nameIdentifierURI":"http://researchmap.jp/read0004211"}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2019-03-16"}],"displaytype":"detail","filename":"narc_report_No9p17-74p.pdf","filesize":[{"value":"10.7 MB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"narc_report_No9p17-74p.pdf","url":"https://repository.naro.go.jp/record/1569/files/narc_report_No9p17-74p.pdf"},"version_id":"e98b0de2-61e5-495c-a03a-c312b173c7e5"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"jpn"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"departmental bulletin paper","resourceuri":"http://purl.org/coar/resource_type/c_6501"}]},"item_title":"クモヘリカメムシの発生動態ならびに斑点米被害予測に関する研究","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"クモヘリカメムシの発生動態ならびに斑点米被害予測に関する研究"},{"subitem_title":"Population Dynamics of Leptocorisa chinensis (Hemiptera: Alydidae) and Forecasting of Damage Occurrence in Rice Fields","subitem_title_language":"en"}]},"item_type_id":"10002","owner":"12","path":["203"],"pubdate":{"attribute_name":"公開日","attribute_value":"2019-03-22"},"publish_date":"2019-03-22","publish_status":"0","recid":"1569","relation_version_is_last":true,"title":["クモヘリカメムシの発生動態ならびに斑点米被害予測に関する研究"],"weko_creator_id":"12","weko_shared_id":12},"updated":"2023-05-15T16:23:18.342320+00:00"}