Tea Thrips Research Articles

チャノキイロアザミウマで検出されたフェンプロパトリン水和剤抵抗性に関与するナトリウムチャネル遺伝子の点突然変異とPCR-RFLP法による抵抗性個体の判別

We analyzed part of the sodium channel gene to clarify the molecular mechanism involved in the pyrethroid resistance of the yellow tea thrips (Scirtothrips dorsalis), and found two amino acid mutations (T929I and L1014F) known as pyrethroid-resistant factors in several other insects. The L1014F mutation was shared with all the tested thrips from a field colony. On the other hand, the T929I mutation was found only in individuals which survived in pyrethroid treatment of agriculturally recommended concentration. This might suggest that pyrethroid resistance of S. dorsalis in the field is conferred by both mutations. We developed the PCR-RFLP assay using MboI to distinguish pyrethroid-resistant individuals.

제주에서 적산온도를 이용한 볼록총채벌레 세대별 발생최성기 예측모형

볼록총채벌레는 제주도 감귤에서 경미한 피해만 보고되다가 2007년부터 다발생하여 그 피해가 갈수록 심각해지고 있다. 본 연구는 적산온도를 이용하여 볼록총채벌레 각 발생세대의 발생최성기를 예측할 수 있는 모형을 개발하고자 수행하였다. 볼록총채벌레 성충 발생세대수를 독립변수(x)로 취급하고 세대별 발생최성기의 적산온도를 종속변수(y)로 취급하여 직선 회귀식을 추정하였다. 감귤원에서 유살된 자료와 녹차 또는 키위과원에서 얻은 자료를 기반으로 각각 감귤기반모형(y = 310.9x + 69.0, <TEX>$r^2$</TEX>=0.99) 녹차기반모형(y = 285.7x + 84.1, <TEX>$r^2$</TEX>=0.99)을 개발하였다. 각 모형의 예측값과 독립된 포장 실측자료와의 잔차자승합을 토대로 모형의 적합성을 평가하였으며, 녹차기반모형의 적합력이 좋았다. 본 예측모형을 통한 계산값과 실측치의 불일치에 대한 원인과 모형의 포장 활용도에 대하여 고찰하였다. The yellow tea thrips, Scirtothrips dorsalis (Thysanoptera: Thripidae), has been regarded as a minor pest on citrus on Jeju Island. However, the damage of yellow tea thrips has gradually increased since 2007. This study was conducted to develop a forecasting model for generation peak time of S. dorsalis by using degree-days. Simple linear regression analysis was applied to determine the relationship between the generation number (x, dependent variable) and degree-days (y, independent variable). As a result, two regression models were established: citrus-based model (y = 310.9x + 69.0, <TEX>$r^2$</TEX>=0.99) and green tea-based model (y = 285.7x + 84.1, <TEX>$r^2$</TEX>=0.99). The models was fitted by independent data sets obtained from 2013 and evaluated using the technique of RSS (residual sum of square) and <TEX>${\chi}^2$</TEX>-test. The green tea based-model showed a good fitting ability. The discrepancy between model outputs and actual data, and the practical application of models were discussed.

静岡県の茶園から採集したチャノキイロアザミウマに対する薬剤の殺虫効果

静岡県の茶園から採集したチャノキイロアザミウマに対する薬剤の殺虫効果

노지재배 감귤에서의 볼록총채벌레 발생 양상과 피해 증상

최근 들어 노지재배 감귤에서 볼록총채벌레에 의해 검은점무늬병 후기 증상 및 녹응애 피해 증상과 매우 유사하게 과정부 주위를 중심으로 검붉게 그을린 증상 또는 조직이 회갈색으로 괴사되어 딱지형태가 되는 증상들이 2007년부터 서귀포시 남원읍 일부지역에 발생하여 큰 피해를 주고 있다. 황색 끈끈이 트랩을 이용하여 7일 마다 발생 밀도를 조사한 결과 2009년의 경우 5월 상순부터 발생하기 시작하여 꾸준히 증가하다 8월 하순에 밀도가 가장 높았으며 2010년과 2011년의 경우 10월 상순에 밀도가 가장 높았다. 2009년의 경우 5월부터 10월 하순까지 최소 7회의 발생 세대를 보였고 통상 7월 경부터 볼록총채벌레가 감귤원에서 우점하여 발생하였다. 과실에서 볼록총채벌레 약충들이 7월부터 발견되어 2009년의 경우 8월 하순부터 9월 중순, 그리고 10월 상순에 피크를 보였고 피해 증상은 9월 중순부터 발생하기 시작하였다. 2011년의 경우 7월 상순에 밀도가 매우 높았으며 이후 9월 하순에 다시 밀도가 증가하였고 피해 증상은 7월 중하순 부터 발생하기 시작하여 10월 하순까지 계속적으로 증가하였다. 피해증상은 과정부를 중심으로 회색빛으로 부스럼같이 코르크화 되거나 초기에 검은색을 띄다가 착색기에 접어들어 과피가 검붉게 변하였다. 감귤에서 볼록총채벌레에 의한 이런 피해 증상을 국내에 처음으로 보고한다. Silver-grey or dark brown scaring, or dark brown discolored damages caused by the yellow tea thrip, <TEX>$Scirtothrips$</TEX> <TEX>$dorsalis$</TEX> Hood (Thysanoptera: Thripidae) have occurred on citrus fruits cultivated in the open field in east-south area orchards of Jeju Island since 2007. The weekly population of yellow tea thrips adults caught with a yellow sticky trap increased gradually from early May and peaked in late August, 2009. In 2010 and 2011, the most population was in early October. The yellow tea thrips of some species usually dominated from July in open citrus fields, and seven generations, at least, had occurred from May to late October 2009 by a yellow sticky trap survey. In 2009, <TEX>$S.$</TEX> <TEX>$dorsalis$</TEX> larva were observed from July and with peaks from late August to mid September and early October on citrus fruits. The damage symptoms appeared in the mid September. In 2011, the population peaks were in early July and late September, and the symptoms increased continually from mid July to late October. The symptoms were silver-scars or initial dark discolorations and then gradually changed to dark-brown discolorations or dark-brown scars. The percent of damaged fruits were 0.9%, 0.4%, 0.8% and 2.7% in 2008, 2009, 2010 and 2011, respectively, by survey in 64 typical orchards in Jeju Island. We are the first to report symptoms of the yellow tea thrip (<TEX>$Scirtothrips$</TEX> <TEX>$dotsalis$</TEX>) on citrus fruits.

Neem based Integrated Approaches for the Management of Tea Thrips Scirtothrips dorsalis Hood (Thripidae: Thysanoptera) in Tea

Tea thrips, Scirtothrips dorsalis Hood (Thripidae: Thysanoptera), has been the most destructive pest of tea in North East India since last few decades. In order to reduce the load of the synthetic chemicals in tea vis-a-vis their deleterious effect, integration of biopesticides, synthetic pesticides along with effective spraying strategies, have been attempted. The anti-insect property of “neem”, Azadirachta indica A. Juss. (Meliaceae) has been used to solve many pest problems. Two field trials were conducted between May and June 2008 at Red Bank Tea Estate, Jalpaiguri, West Bengal, India following randomized block design against tea thrips, S. dorsalis. In one experiment, different azadirachtin concentrations (300, 1,500, 3,000, 10,000 and 50,000 ppm) at different doses (1:200, 1:300, 1:500, 1:1,000 and 1:1,500) were evaluated to find out the relationship between azadirachtin concentration and its bioactivity against S. dorsalis. At 50,000 ppm azadirachtin concentration 82% control of reduction in thrips population could be attained, whereas at 3,000 and 10,000 ppm, gave 60–73% reduction and 300 and 1,500 ppm <60% control was possible. Therefore, azadirachtin concentration and its dilutions are the major criteria to determine the bioactivity against tea thrips. In another field experiment, a neem formulation alone and in combination with Tea Research Association recommended and reduced dose of endosulfan and monocrotophos were tested. Treatments with combined formulations (neem + insecticide) recorded significant reduction in S. dorsalis incidence even at reduced doses (1:600 and 1:800), as compared to sole application of neem or synthetic insecticide at recommended doses. Azadirachtin concentrations and their bioactivity, effective combinations and dose of the insecticides along with their formulations in controlling S. dorsalis have been presented and discussed.

Regional differences in the density of phytoseiid mites and yellow tea thrips Scirtothrips dorsalis Hood on the windbreaks of bigleaf podocarp trees surrounding citrus orchards

In 2007, I determined the densities of phytoseiid mites and yellow tea thrips Scirtothrips dorsalis Hood on the windbreaks of bigleaf podocarp trees Podocarpus macrophyllus that surround citrus orchards in Nishiura and Mikkabi region in Shizuoka prefecture. In the Nishiura region, phytoseiid mites such as Amblyseius eharai, Euseius sojaensis, and Neoseiulus californicus were observed on the windbreaks throughout early May to late July. In the Mikkabi region, phytoseiid mites were not detected on the windbreaks in May, but the density of phytoseiid mites increased slowly on the windbreaks from early June to early July. The total number of phytoseiid mites observed between early May and late July on the windbreaks in the Nishiura region was greater than that in the Mikkabi region. And consequently, the number of S. dorsalis larvae and adults observed on the windbreaks between early June and late July in the Nishiura region was smaller than that in the Mikkabi region. These results suggest that phytoseiid mites can lower the density of S. dorsalis on windbreaks of bigleaf podocarp trees.

Effects of vegetation around citrus orchards on the amount of citrus fruits damaged by yellow tea thrips Scirtothrips dorsalis Hood

Effects of vegetation around citrus orchards on the amount of citrus fruits damaged by yellow tea thrips Scirtothrips dorsalis Hood

Effect of pyrethroid insecticide on yellow tea thrips, Scirtothrips dorsalis Hood with grape leaf dipping method

Effect of pyrethroid insecticide on yellow tea thrips, Scirtothrips dorsalis Hood with grape leaf dipping method

チャノキイロアザミウマ成虫の飛翔による分散時期と移動距離

In 2001 and 2002, dispersal by the flight of adult yellow tea thrips, Scirtothrips dorsalis Hood was studied using yellow sticky traps placed in tea groves and in an adjacent lawn, i.e., an open space. At the peak of the population density for each generation of S. dorsalis adults inhabiting the tea groves, the number of adults captured in each trap reached its peak. The number of S. dorsalis adults captured using the traps decreased with the increase in distance from the tea groves for each generation. These results suggest that S. dorsalis adults actively make shorts flights when their population density increases at their reproduction sites. The sex ratio (number of females/total number of males and females) of the adults captured by the traps was significantly biased toward females as compared to those inhabiting the tea groves.

奄美大島のハウスマンゴーにおけるチャノキイロアザミウマとアカオビアザミウマの花芽，花房ならびに果実での発生推移

The yellow tea thrips, Scirtothrips dorsalis Hood, and the red-banded thrips, Selenothrips rubrocinctus (Giard), cause serious damage to the epicarp of the fruits of mango (Mangifera indica L.). I investigated seasonal prevalence of both these thrips species on the flower buds, inflorescences, and fruits of mango plants cultivated in greenhouses on Amami-Oshima Island. Scirtothrips dorsalis was regularly found on flower buds, inflorescences, and young fruits. The number of thrips on fruits decreased with the growth of the fruits. In contrast, Selenothrips rubrocinctus was observed only on fruits, and not found on flower buds and inflorescences. With regard to Selenothrips rubrocinctus, the number of thrips on fruits increased proportionately with the growth of the fruits. Neither Scirtothrips dorsalis nor Selenothrips rubrocinctus were observed on ripe fruits.

チャノキイロアザミウマ越冬成虫の産卵時期

The reproduction period of overwintered adults of yellow tea thrips, Scirtothrips dorsalis Hood (Thysanoptera: Thripidae) was investigated in tea groves and adjacent bigleaf podocarps trees (Podocorpus marcrophyllus). Overwintered adult S. dorsalis females started egg development from late March to early April while inhabiting tea groves that sprout in late March. First-generation larvae were found in the tea groves from late April to early May, and adults began to emerge in mid-May. First-generation larvae were barely detected in bigleaf podocarps trees that sprouted from mid- to late April. First-generation adults moved to bigleaf podocarp trees in mid-May, and second-generation larvae occurred from late May to early June.

Synchronism of immigration of adult yellow tea thrips, Scirtothrips dorsalis Hood (Thysanoptera: Thripidae) to citrus orchards with reference to their occurrence on surrounding host plants

Scirtothrips dorsalis adults generally immigrate to citrus orchards after propagation on suitable host plants that grow near the orchards; however, it is not clear when these thrips immigrate. In this study, the time of S. dorsalis adult immigration to citrus orchards was examined in relation to their occurrence on surrounding host plants. The investigation was carried out in citrus orchards and the surrounding fields of the following three plants: tea groves, bigleaf podocarp trees, and Japanese pear trees. The average number of adults emerging from these four plant fields gave six or seven peaks from May to early September, notwithstanding the small number of adults emerging from the citrus orchards. The peak periods of trap catch in citrus orchards coincided with those of adult emergence from the fields of four plants. The peak periods of adult S. dorsalis density on citrus fruits and shoots coincided with those of trap catch in citrus orchards. These results demonstrated that S. dorsalis adults immigrated to citrus orchards immediately after emerging from other suitable host plants surrounding the orchards.

ブドウにおけるチャノキイロアザミウマとコウズケカブリダニの個体群密度に及ぼす薬剤散布の影響

The insecticide susceptibility of yellow tea thrips, Scirtothrips dorsalis and its natural enemy mite, Euseius sojaensis was evaluated at 25°C under 16L8D. Imidacloprid was highly effective against S. dorsalis second instar larvae. Permethrin was effective at 100–200 ppm and marginally effective at 25–50 ppm. Imidacloprid was not harmful to E. sojaensis female adults, while permethrin was seriously harmful. The effect of insecticide application on the population of S. dorsalis and E. sojaensis was investigated in a Delaware vineyard in Osaka Prefecture. With the application of imidacloprid, the density of S. dorsalis was effectively reduced, and E. sojaensis was found to survive on the grapes. In contrast, the density of S. dorsalis was slightly reduced, and E. sojaensis was not found on the grapes with the application of permethrin. Injury to fruit by S. dorsalis was significantly lower on grapes with imidacloprid application. The results suggest that imidacloprid did not seriously affect the population of E. sojaensis but shows good control against S. dorsalis on grapes.

Seasonal fluctuation in population density of phytoseiid mites and the yellow tea thrips, Scirtothrips dorsalis Hood (Thysanoptera: Thripidae) on grape, and predation of the thrips by Euseius sojaensis (Ehara) (Acari: Phytoseiidae)

Seasonal fluctuation in population density of phytoseiid mites and Scirtothrips dorsalis and species composition of phytoseiid mites were investigated from May to September in 1997 and 1998 in a Delaware vineyard in Osaka Prefecture. Phytoseiid mites were found in high densities from mid-July to mid-August in 1997 and from mid-July to mid-September in 1998. S. dorsalis was found in high densities from late June to late July both in 1997 and in 1998. The dominant species of phytoseiid mites investigated in 1998 were Euseius sojaensis from mid-June to mid-August and Amblyseius eharai from late August to late September. The numbers of S. dorsalis larvae consumed per hour and day by E. sojaensis were 1.4 and 5.4, respectively. The results suggest that the population increase of E. sojaensis corresponds to that of S. dorsalis and affects the population density of the thrips as a predator on grape.

多孔質ポリシートによる地表面マルチのチャノキイロアザミウマに対する忌避効果

多孔質ポリシートによる地表面マルチのチャノキイロアザミウマに対する忌避効果

Scirtothrips dorsalis . [Distribution map

Abstract A new distribution map is provided for Scirtothrips dorsalis Hood [Thysanoptera: Thripidae] Chilli thrips, flower thrips, yellow tea thrips, Assam thrips Polyphagous, attacks grapevine, rubber, tea, castor, strawberry, Capsicum (chilli), tamarind, groundnut, soyabean, asparagus, citrus, mango, passionfruit, etc. Information is given on the geographical distribution in ASIA, Bangladesh, Brunei, China, Hongkong, India, Indonesia, Japan, Malaysia, Pakistan, Sri Lanka, Sulawesi, Taiwan, Thailand, AUSTRALASIA, AND PACIFIC ISLANDS, Australia, Papua New Guinea, Solomon Islands.

Effect of white wash treatment of satsuma orange to the damage caused by yellow tea thrips (Scirtothrips dorsalis Hood)

Effect of white wash treatment of satsuma orange to the damage caused by yellow tea thrips (<i>Scirtothrips dorsalis</i> Hood)

Control of Yellow Tea Thrips, Scirtothrips dorsalis HOOD, in Tea Field at East Region in Shizuoka Prefecture

近年,静岡県東部地帯において発生が増加しているチヤノキイロアザミウマに対し,既存の農薬を用いて防除効果を上げる方法を検討した。その結果,2回以上の連続散布を行うのが効果的であり,その場合の間隔は5日前後がよいと考えられた。また,被害を最少限にするためには,萌芽～開葉期の防除が重要である。2回散布に際しては,同一薬剤によるより,異なった薬剤を組合せることで効果の増大がはかられ,さらに他害虫の同時防除も可能となる。これらの条件を満す方法として,萌芽期にメソミル1,500倍,開葉期にカルタップ1,000倍を散布する方法が効果的であった。

Effect of some chemical compounds on citrus fruit injured by yellow tea thrips

Effect of some chemical compounds on citrus fruit injured by yellow tea thrips