静岡県内のジチオカーバメート系薬剤の散布状況が異なる３圃場で採集したミカンサビダニに対する各種薬剤の殺虫効果を評価した。その結果，すべての個体群に対してマンゼブおよびビフェナゼートの効果が低いと判定された。一方，すべての個体群に対して，レピメクチン，ミルベメクチン，ルフェヌロン，アミトラズ，アセキノシル，ピリダベン，トルフェンピラド，スピロメシフェン，フルアジナム，キノキサリンの効果が高いと判定された。さらに，１個体群で本害虫に登録がない薬剤の殺虫効果を検定した結果，エチプロール，スピノサド，ピリフルキナゾン，ヘキシチアゾクス，ブプロフェジン，スピロテトラマト，シエノピラフェン，シフルメトフェン，シアントラニリプロール，フルベンジアミド，メパニピリムの効果が高いと判定された。これらミカンサビダニに対する殺虫効果が高い薬剤の中には，カンキツ微小害虫の土着天敵に対する影響が大きい薬剤も含まれるため，ミカンサビダニの化学的防除では土着天敵に悪影響を及ぼさないよう，使用薬剤の種類や散布時期に注意する必要がある。

アブラムシ類に対する生物的防除であるバンカー（植物）法の実用性を高めるため，ムギクビレアブラムシの増殖に及ぼす土壌水分および寄主植物の影響を以下の２つの試験により検討した。試験１：エンバク‘ヘイオーツ’，コムギ‘さとのそら’，オオムギ‘てまいらず’，ライムギ‘007’などの８種の植物を，生産地のピーマン栽培施設内において土壌水分が異なる３箇所（pF＝1.8，2.0，2.2）に植栽した。試験２：土壌水分を異なる２水準（pF＝1.8およびpF＝2.3）で維持管理した条件で，上記と同一の８種の植物を植栽した。両試験においてムギクビレアブラムシの増殖を比較した結果，本種の個体数は，生産地施設内における寄主植物の植栽場所によって有意に異なった（試験１）が，試験２においては土壌水分の相違による有意な差は認められず，土壌水分だけで本種の増殖の相違を説明することはできなかった。本種個体数は，両試験において寄主植物によって有意に異なり，エンバク，コムギおよびライムギが本種の増殖に適したバンカー植物であると推察された。

2015年に大阪府内においてバラ科樹木の害虫として世界的に知られているクビアカツヤカミキリ（Aromia bungii）が発見された。そこで，2015年から2017年に大阪府域において本種の宿主であるバラ科樹木を対象に被害状況を調査した。調査地において被害木は年々増加し，いくつかの被害木はおそらく本種の加害が原因で枯死した。

サクラにおいては根元周が大きな木ほど被害を受けていた。一方で，同じ被害程度のサクラを根元周別に比較すると，大きな木ほど樹勢への影響を受けにくく，小さな木ほど枯損しやすい傾向にあった。

被害木の被害部位の最高地上高は，大部分の被害木が地上から 2 mより低かった。また，被害を受けてからの年数が経過した被害木ほど被害部位の最高地上高は高かった。

シソサビダニとシソモザイク病の防除技術の開発のため，アオジソ（オオバ）葉上でのシソサビダニの発生消長と枝ごとのシソモザイク病の発病頻度を調査した。

シソサビダニは，アオジソ漏生株で４月から６月に発生を確認し，その後，隣接した露地ほ場でも発生し，約３か月後には，約 50 m離れた施設ほ場でも発生した。各ほ場では，シソサビダニの発生盛期は，７月から10月で，シソモザイク病は，最初のシソサビダニの発生確認と前後して，７月から９月に急激に発病が拡がった。このため，屋外から施設へのシソサビダニの侵入と，極めて低密度のシソサビダニによるシソモザイク病の伝搬の可能性が示唆された。

枝ごとのシソモザイク病の発病頻度は，保毒虫放飼後40日目には急増したが，放飼後69日目には減少し，放飼後96日目でも同様で，発病後に新たに発生した枝でシソモザイク病が消失する現象が確認された。しかし，見かけ上の健全枝から発生した枝で再び発病する事例があり，見かけ上の健全枝でもシソモザイク病の感染は続き，伝染源となると考えられた。

これらにより，シソサビダニとシソモザイク病の防除には，伝染源となりうる施設内外の発病したシソ類の除去，そして，シソサビダニ発生始期前の防除が重要であると考えられた。

ブドウ晩腐病の防除のため，病原菌の胞子飛散盛期にあたる６月から７月に露地栽培の‘巨峰’に対してQoI剤ではない殺菌剤（ペンチオピラド，キャプタン）とQoI剤を各２回ずつ散布し，発病状況を調査したところ，アゾキシストロビン（QoI剤），ピラクロストロビン・ボスカリド（QoI剤混合剤），キャプタン，ペンチオピラドの順で防除効果が高かった。また，果粒表面に対する各殺菌剤の影響を調査したところ，果粒の大きさがダイズ大を超えた時期にピラクロストロビン・ボスカリドを散布すると果粉の溶脱が生じ，アズキ大からダイズ大程度の時期での散布では果粉の溶脱は実用上問題とならなかった。

静岡県内のウンシュウミカン園ではミヤコカブリダニがミカンハダニの主要な天敵となっている。しかし，清耕栽培が行われる栽培園では，地面付近におけるカブリダニ類の生息場所が少ない。カブリダニ類の発生を助長するため，草生栽培が有効と指摘されている。また，ミヤコカブリダニはイネ科植物への生息の報告がある。そこで，2004～2005年にイネ科植物であるナギナタガヤの草生栽培を実施し，カブリダニ類およびミカンハダニの発生を清耕栽培と比較した。その結果，出穂後のナギナタガヤからミヤコカブリダニが捕獲され，ナギナタガヤ枯死後にウンシュウミカン上からも捕獲された。草生区のカブリダニ発生時期は除草区より１～５週間早く，夏季のミカンハダニの密度ピークは除草区の 11～59％にとどまった。少数であったが，秋季～冬季のナギナタガヤからミヤコカブリダニが分離された。これらのことから，ウンシュウミカン園のナギナタガヤ草生栽培は，春季のミヤコカブリダニの発生を助長し，夏季のミカンハダニの密度抑制に有効と考えられた。

ネギ黒腐菌核病（Sclerotium cepivorum）に重度に汚染されたネギ（Allium fistulosum L.）圃場において，作付前の転炉スラグ施用による被害軽減の効果について検討した。定植前の全面スラグ施用により，収穫時の重症株（廃棄株）の割合は，事前の土壌消毒の有無に関わらず，無処理区に比べ顕著に減少した（土壌消毒有り：74.7％→16.7％，土壌消毒無し：82.0％→50.7％）。翌年の同一圃場における作付では，前作より効果が低下したものの，追加の転炉スラグ施用をしなくても発病軽減が認められた。また施用場所をネギの植え溝部分に限定し，転炉スラグ量を減らして施用した場合の効果を検討した結果，無処理区と比べ発病の軽減が認められた。以上の結果は，定植前の転炉スラグ施用によりネギ黒腐菌核病を軽減できることを示している。

大阪府内の半促成ナス栽培を行う現地施設において，天敵温存植物・スイートアリッサムのナス株間への植栽と代替餌・アルテミア耐久卵を麻ひもに付着させた資材のナス株上への設置を行った条件で，飛ばないナミテントウ２および３齢幼虫の３回放飼とコレマンアブラバチ成虫の２回放飼を実施し，約３か月（４月下旬～７月下旬）にわたりアブラムシ類の密度の推移を調査した。無処理との比較はできなかったが，アブラムシ類（モモアカアブラムシ主体）は試験期間を通じて低密度に維持され，これら天敵２種および温存植物と代替餌を組み合わせた防除体系によるアブラムシ密度の長期抑制が示唆された。

2014年，2015年に府内で発生したキュウリのウイルス病について病原ウイルスを調査したところ，ズッキーニ黄斑モザイクウイルス（ZYMV）の感染が多いことが明らかとなった。また，ZYMV感染によっておこる萎凋症に対する遮光の効果を調査したところ，遮光によりハウス内の温度を下げることは効果的であるが，６～８葉期にZYMVに感染すると萎凋症の発生が多かったため，13～15葉期まではウイルスに感染しないようアブラムシの防除を徹底する必要があると考えられる。さらに，遮光とZYMVワクチンの併用による効果を調査したところ，ワクチン処理単独の場合よりもZYMVによる収量減少を軽減できる可能性が示唆されたが，ワクチン処理後すぐの３～４葉期にZYMVを接種すると遮光ハウスおよび無遮光ハウスともにワクチン無処理区と収量は同等であった。このことから，ワクチン処理と遮光を併用した場合でも６～８葉期まではZYMVに感染しないようアブラムシの防除を重点的に行う必要があると考えられる。

夏まきエンドウを加害するウラナミシジミの成虫，卵およびふ化幼虫に対する薬剤の殺虫効果ならびにふ化幼虫の莢への食入阻止に効果がある薬剤を調査した。

その結果，成虫に対しては殺虫効果が高かった７剤の内，ピレスロイド系のエトフェンプロックス乳剤，ペルメトリン乳剤，フルバリネート水和剤およびトラロメトリンフロアブル剤は速効的な効果が見られ，広範囲の一斉防除によって高い産卵防止効果を発揮すると考えられた。

卵とふ化幼虫に対して殺虫効果が高かった10剤の内，殺卵効果とふ化幼虫にも殺虫効果が高かったエマクチン安息香酸塩乳剤，スピノサド水和剤，エトフェンプロックス乳剤およびアセタミプリド水溶剤は産卵部位である花蕾への散布で安定した防除効果が期待できると考えられた。

ふ化幼虫の莢への食入阻止効果が高かった10剤の内，莢表面の食害痕が見られなかったカルタップ水溶剤，マラソン乳剤，エトフェンプロックス乳剤，ペルメトリン乳剤およびフルバリネート水和剤は，着莢時の防除における実用性が高いと考えられた。

トマト青枯病菌に対する土壌還元消毒の新規資材として，糖含有珪藻土または糖蜜吸着資材を用いた場合の処理条件について検討した。両資材とも，土壌に対して重量比で 1％以上混和して土壌還元消毒処理すると，青枯病菌に対して対照の廃糖蜜 0.6％処理に優る効果が得られることが示唆された。また，20～50°Cの範囲では温度が高いほど還元が進んだ。和歌山県で７～８月に施設内で土壌消毒を実施すると，地下 30 cmでは 40°C以上を12日間維持できた。一方，地下 40 cmでは，みなべ町では処理開始13日後以降 40°C以上を維持したが，海南市では 40°Cに達することはなかった。これらのことから，地下 30 cmより浅い層では高地温による菌密度低減と還元による菌密度低減が併せて起こり，地下 30～40 cmより深い層では溶出した糖含有珪藻土および糖蜜吸着資材の成分による還元が起こって菌密度が低減することが期待される。

Ceratocystis canker is one of the most serious diseases of figs, Ficus carica, in Japan. Some fungicides, such as triflumizole WP (T) and thiophanate-methyl WP (TM), have been drenched monthly to control the disease. However, these fungicides are not applied during harvest season because of registration restrictions, and losses of soil drench during harvest season were feared. We evaluated effectiveness of control with soil drenches of the newly registered tebuconazole WP (TE), which can be used up to the day before harvest. We planted fig cuttings in the soil contaminated with Ceratocystis ficicola, causal agent of Ceratocystis canker. Treatments were as follows: 1) control, 2) existing treatment (T and TM drenched bimonthly from April to October, except for the harvest period from August to October), 3) existing treatment plus TE at harvest (TE drenched monthly from August to October). Cumulative death rates of plants in each treatment were evaluated for 3 years. More than half of the plants died in the control, and less than half of plants died in the existing treatment. On the contrary, no plants died in the existing treatment plus TE. These results suggest that existing treatment plus TE possess high control effect against the disease.

We investigated the effect of various plants on the population density of Plasmodiophora brassicae, which causes clubroot disease in crucifers. The amount of P. brassicae in soil samples was measured using quantitative real-time PCR (qPCR). The impact of the plants used in this study was generally small under both greenhouse and field conditions. P. brassicae does not cause clubroot disease in leaf radish (ha-daikon), but is known to be able to proliferate in the root hairs of the plant. The qPCR could also detect an increased density of P. brassicae in soil where leaf radishes were grown.

The effects of utilization of agricultural mulch sheets against brown rot on Citrus unshiu were examined in this study. This disease is caused by Phytophthora palmivora and P. nicotianae which were observed during two cultural seasons from 2016 to 2017. The difference in the number of diseased fruits in mulching cultivation areas and open cultivation areas was surveyed. As a result, it was revealed that utilization of agricultural mulch sheets is effective to control the disease.

We demonstrated a method for the quick discrimination of live and dead sclerotia of the allium white rot pathogen (Sclerotium cepivorum Berkeley) by vital staining with fluorescein diacetate (FDA) hydrolysis. Surface-sterilized sclerotia were cracked by forceps and placed on a water agar plate. Within 20–30 min after the application of 1.25–10 ppm FDA, bright green fluorescence was observed from within and around the sclerotia under blue light (480 nm ). Water agar (background) and autoclaved (dead) sclerotia emitted negligible fluorescence with 10 ppm FDA. Inhibition of sclerotial germination by cyanamide did not affect fluorescence. FDA application did not suppress germination and growth of sclerotia. This method can be used to assess the viability of sclerotia quickly.

To estimate the influence of harvest timing on the severity of allium white rot (caused by Sclerotium cepivorum Berkeley) of Welsh onion (Allium fistulosum L.), we compared the severity of white rot during 5 cropping periods. The rate of plant death was significantly lower during the 2 earlier cropping periods (15 June–24 Nov., 30 June–16 Dec.) than during the 3 later periods (15 Jul.–14 Jan., 5 Aug.–28 Jan., 19 Aug.–28 Jan.). The results indicate that earlier cropping allowing harvest in December can avoid severe damage by white rot because of the shorter cool soil period (daily average <15°C).

We investigated the efficiencies of several treatments to control clubroot disease caused by Plasmodiophora brassicae on ‘Tennoji-kabura’ turnip (Brassica campestris L. ‘Tennoji-kabura’), a traditional vegetable in Osaka, Japan. Growing ‘Tanabe-daikon’ (Japanese radish) for 1.5 months as a decoy plant reduced the gall formation as is in the case of growing leafy daikon breeding line CR-1. Dolomite-converter slag raised the soil pH from 6.8 to 7.5, and remarkably suppressed the gall formation in ‘Tennoji-kabura’. A commercial seaweed fertilizer did not yield a significant effect.

Wild soybean consumption by nine species of coleopteran adults and two species of Trachyinae larvae was investigated for the environmental assessment of Bt soybean. The leaf area eaten by the coleopteran adults per day was 1158, 915, 599, 30, 22, and 6 mm² for Mimela splendens, Anomala rufocuprea, Epicauta gorhami, Medythia nigrobilineata, Trachys reitteri, and Pagria ussuriensis, respectively. The total area eaten by the Trachyinae larvae was 200 and 599 mm² for T. reitteri and T. auricollis, respectively.

The control effects of 14 insecticides on the diamondback moth, Plutella xylostella (Linnaeus), collected from Komatsuna, Brassica rapa L.var. perviridis, in Wakayama City, were investigated at 3rd instar larvae using the leaf-dipping method. Spinetoram, spinosad, emamectin benzoate, and two BT-insecticides exhibited high insecticidal activity. Flufenoxuron, chromafenozide, cypermethrin, chlorantraniliprole, and flubendiamide had low efficacity. Lepimectin showed relatively low efficacy on the 4th day after treatment, but all individuals died later. Mortality rates associated with lepimectin, pyridalyl, metaflumizone, and chlorfenapyr in the Nagusa population were lower than these in the Kasei population.

The efficacy of insecticides against adults of the Hawaiian flower thrips, Thrips hawaiiensis (Morgan), and larvae of the garden pea leafminer, Chromatomyia horticola (Goureau), on the garden pea (snap pea), Pisum sativum L., was evaluated under laboratory conditions. Seven insectides (cartap, chlorfenapyr, clothianidin, emamectin, phenthoate, imidacloprid, and spinetoram) were effective against T. hawaiiensis adults and three insecticides (chlorantraniliprole, imidacloprid, and spinetoram) were effective against C. horticola larvae.

We examined the nymphal development of the fruit-piercing stink bug, Glaucias subpunctatus, a pest of citrus and pears, on mature capsules of the Chinese tallow-tree, Triadica sebifera, considered to be an alternative host plant. The rearing experiment revealed that all nymphs after the second instar stage developed and survived to adulthood, but a large proportion of the second instar nymphs died, considered to be due to sucking failure. The marked mortality of the second instars may be due to the hard seed coat of T. sebifera. In conclusion, T. sebifera may be an alternative host plant after the successful passage of second instars on immature capsules of T. sebifera, or on Cryptomeria japonica or Chamaecyparis obtuse, conventionally viewed as the host plants.

We estimated the density of shoot blight from Pestalotiopsis longiseta and rolled leaves produced by Adoxophyes honmai or Homona magnanima in tea fields using a direct counting method based on aerial photography from a multirotor-type drone. We used a DJI Phantom 4 to conduct aerial photography of shoot blight and rolled leaves. We then counted the densities of both the diseased and rolled leaves in-situ. We examined the aerial photographs on a LCD, and identified and counted the densities of both the diseased and rolled leaves. The relationship between the densities of shoot blight counted using the LCD and in-situ was R² = 0.69 and 0.76, respectively. The accuracy of estimation using the LCD was about 80%. These results suggested that estimation of the density of shoot blight based on aerial photography was effective. For the rolled leaves, the accuracy of counting using an LCD increased to about 60% from <40%, after comparing to the first count.

We examined the effect of 13 pesticides by using the kidney bean leaf-dipping method on the 1st instar larvae, 3rd-4th instar larvae, and adults of Q-biotype Bemisia tabaci (Gennadius) collected from three major tomato-growing districts in Aichi Prefecture. The effects of the pesticides on Q-biotype were almost the same as previously reported, whereas those of pyridaben WP and tolfenpyrad WP were lower. In addition, the appropriate timing for applying the pesticides in forcing culture, the main tomato cultivation method in Aichi prefecture, is discussed based on our study results.

We investigated the ability of phytoseiid mites in intercropped barley to suppress onion thrips (Thrips tabaci Lindeman) on Welsh onion in the laboratory. Ten adult females of T. tabaci were released into a cage containing Welsh onion seedlings planted in a pot and intercropped with barley transplanted from a Welsh onion field. For comparison, insecticide-treated barley and soil from the Welsh onion field were tested. At 20 days after release, the number of T. tabaci was lowest (significantly) in the untreated barley, but there was no change in the treated barley. Phytoseiid mites (mainly Gynaeseius liturivorus (Ehara)) were observed only in untreated barley.

Control effects of etoxazole spraying were investigated for cotton aphid, Aphis gossypii Glover and potato aphid, Macrosiphum euphorbiae (Thomas) on strawberry. Densities of both aphid species were suppressed 3–14 days after spraying. Results show that etoxazole is effective to control aphids on strawberry.

Toxicities of 21 insecticides for Tetranychus kanzawai Kishida collected from a strawberry field in Nara Prefecture were investigated. Corrected mortality rates of these insecticides, except malathion, were almost 100%. Chemical control of T. kanzawai was inferred as possible by spraying these insecticides.

Toxicities of insecticides for adult females of Tetranychus urticae Koch collected from five chrysanthemum fields in Nara Prefecture were investigated. The corrected mortality rates of bifenazate were 100% in all populations. The rates of acequinocyl and abamectin were higher than 80% in three and four populations, respectively. No significant decrease of susceptibility was found. The rates of milbemectin and emamectin benzoate were lower than 50% in one or two fields, respectively. The rates of cyenopyrafen, pyflubumide-fenpyroxymate, spinetoram were lower than 28.4% in all fields.

The first generation of crawlers of arrowhead scale Unaspis yanonensis (Kuwana) occur in citrus orchards from early May to late July. Insecticide application is generally carried out to control U. yanonensis during the peak days of larval occurrence in June. We demonstrated that a high synergistic effect in controlling U. yanonensis was observed with the combined application of petroleum oil (9.7 g/L) and buprofezin (0.2 g/L) at the adult stage in late April. However, independent application of each insecticide during this time was less effective in controlling U. yanonensis.

Seven insecticides were treated against cotton ballworm larvae with kidney bean leaves. Two days after treatment, all insecticides were found to have high toxicity at commercial and 1/10 of this concentrations. It was thought that chemical control of cotton ballworm can be accomplished using rotation spray of these insecticides.

For two western flower thrips (WFT) populations collected from chrysanthemum fields in Nara prefecture, toxicities of seven insecticides were investigated. Fipronil was most effective in terms of corrected mortality, followed by prothiofos and chlorfenapyr. Tolfenpyrad, thiocyclam and abamectin were less effective in terms of corrected mortality but leaf damages were scarce. Spinosad was less effective in terms of corrected mortality and leaf damage. These result suggest that WFT populations on chrysanthemum in Nara prefecture developed resistance to spinosad.

The species composition and seasonal occurrence of phytoseiid mites on weeds around the eggplant field were investigated by collecting the weeds from April 2016 to March 2017 in Osaka Prefecture, Japan. The phytoseiid mites were extracted from the collected weeds using Tullgren funnels provided with a light bulb. Totally, 288 adult females were sampled, and 12 native and 1 non-native species were identified. The predominant species was Scapulaseius okinawanus (Ehara), accounting for 49.7% of the total number of identified adult females. The second most abundant species was Neoseiulus barkeri (Hughes) (16.3%), followed by Amblyseius tsugawai Ehara (14.2%) and Neoseiulus koyamanus (Ehara and Yokogawa) (7.3%). The four species are all native. Scapulaseius okinawanus was abundant from May to July and in November, and N. barkeri was captured exclusively in September.

The species composition of lepidopteran insects feeding on Japanese pear blossoms was investigated in Kyotango City, Kyoto Prefecture, from late March to late April in 2017. Pasiphila rectangulata (Linnaeus), Archips nigricaudanus (Walsingham), and Ptycholoma lecheana circumclusana (Christoph) were found from early to mid-April. It was reported for the first time that A. nigricaudanus feeds on the blossoms. Pa. rectangulata was predominant of the three species.

In Osaka prefecture, we investigated the species composition of thrips captured from leaves and flowers on cultivated Chrysanthemum morifolium. As results, Thrips nigropilosus was the dominant species on the leaves. But on the flowers, species composition of thrips diversified and dominant species were changed by fields and months. The results suggested that the species composition of thrips depends on the parts of the C. morifolium plant.

Susceptibility of beet armyworm Spodoptera exigua (Hübner) from watermelon to insecticides in Wakayama was determined in the 2nd instar larvae using the leaf dipping method. Spinetoram, spinosad, lepimectin, emamectin, and chlorfenapyr were effective on the 1st day after treatment, whereas pyridalyl and chromafenozide were effective on the 5th day after treatment. Toxicities of emamectin, pyridalyl, and chromafenozide in the Inami population were lower than those in the Gobo population.

Euzophera batangensis Caradja and Synanthedon tenuis (Butler) cause serious damages in persimmon stems. I examine the causes of death in overwinter larvae. In the persimmon trees, dead larvae with white fungi were found frequently. In raring test, although two parasite wasps emerged from E. batangensis larvae, no parasite insects emerged from S. tenuis larvae. Dead larvae with white fungi were found in both species under raring condition. Hatch ratio of E. batangensis was lower than S. tenuis. The difference of parasitism between two stem pests correspond to the tendency of actual specie that injures persimmon stems in spring season.

Enclosing with a red insect-proof net and defuse-reflection mulch sheets were set up in an open fig orchards in Osaka Prefecture in 2017. The dominant thrips species found on the sticky color traps were Thrips tabaci Lindeman from late May to early June and Frankliniella intonsa (Trybom) from mid-June to mid-July. Thrips hawaiiensis (Morgan) was dominant inside fig fruits. The use of these materials effectively prevented thrips from immigrating into the fig orchards, reducing population numbers and infestation of figs. We recommend placing these materials by the middle of May.

We investigated the method for measuring the adhesion amount of medicine sprayed on crops.

Potassium solution as an indicator was sprayed on strawberries, and potassium attached to phylloplane was washed while shaking and collected in a vial. Next, the recovered potassium was measured with an atomic absorption spectrophotometer. When comparing distilled water, 0.025 mol/L hydrochloric acid, and 0.25-N hydrochloric acid, 0.025 mol/L hydrochloric acid was most suitable for potassium recovery. Moreover, since the potassium present in strawberry juice may interfere with the measurement, it is critical that we use leaves that are not scratched.

If we use the insecticide clothianidin or fipronil in a seedling growing box, we can apply the insecticide just before rice planting (hereinafter, termed as “rice planting treatment”) or after seeding and before the seed is covered by soil (hereinafter, termed as “rice seeding treatment”). With the rice seeding treatment, the clothianidin level in plants at the rice-planting stage was 18.4 mg/kg, which was the highest value, and the level rapidly decreased thereafter. With the rice planting treatment, the clothianidin level increased to 1.53 mg/kg 1 day after rice planting and decreased thereafter. The difference in the levels between both treatments at 28 days from the rice planting was small. The fipronil level with rice seeding treatment was higher than that with the rice planting treatment at the rice-planting stage. But there were little differences in the fipronil levels between both treatments after 1 day from rice planting and thereafter.