Comparative Effectiveness of Chemical Insecticides Against the Chilli Thrips

ARTICLE IN PRESS

Crop Protection 25 (2006) 949–955 www.elsevier.com/locate/cropro

Comparative effectiveness of chemical insecticides against the chilli thrips, Scirtothrips dorsalis Hood (Thysanoptera: Thripidae), on pepper and their compatibility with natural enemies

D.R. Seala,Ã, M. Ciomperlikb, M.L. Richardsc, W. Klassena

aUniversity of Florida-IFAS, Tropical Research and Education Center, Homestead, FL 33033, USA bUSDA APHIS PPQ CPHST, Pest Detection Diagnostics and Management Laboratory, 22675 N. Mooreﬁeld Rd., Bldg. 6414, Edinburg, TX 78541-9398, USA cMinistry of Agriculture and Fisheries, St. Vincent, Richmond Hill, Kingstown, St. Vincent and the Grenadines

Received 23 August 2005; accepted 19 December 2005

Abstract

The chilli thrips, Scirtothrips dorsalis Hood, is a significant pest of various vegetable tropical fruit and ornamental crops. Originally from south Asia, this pest is becoming widely distributed in tropical, subtropical and temperate areas, and in 2003 was found for the first time in the Western Hemisphere established on St. Lucia and St. Vincent in the insular Caribbean. Since there is a paucity of information on the effectiveness of modern insecticides in managing S. dorsalis populations, we evaluated the efficacy of the following insecticides for their control of this pest on ‘Scotch Bonnet’ pepper on St. Vincent: spinosad, imidacloprid, chlorfenapyr, novaluron, abamectin, spiromesifen, cyfluthrin, methiocarb, and azadirachtin. Irrespective of the number of applications and use of surfactant, chlorfenapyr was the most effective in reducing the densities of S. dorsalis adults and larvae followed by spinosad and imidacloprid. The performance of other insecticides in controlling S. dorsalis populations was inconsistent. Nevertheless, all of the above insecticides if applied repeatedly were effective in suppressing of S. dorsalis populations. Addition of the surfactant-sticker, Nu-Film 17TM, improved the performance of all insecticides somewhat. Spinosad was slightly harmful and chlorfenapyr was moderately harmful to Cryptolaemus sp. predators. r 2006 Elsevier Ltd. All rights reserved.

Keywords: Scirtothrips dorsalis; Pepper; Insecticides; Chlorfenapyr; Spinosad; Nuﬁlm; Natural enemies

1. Introduction elucidate aspects of the pest’s biology and to develop technology to manage it. In 2003, Skarlinsky, an USDA-APHIS Plant Protection S. dorsalis Hood is a pest of various vegetable, and Quarantine officer, intercepted Scirtothrips dorsalis at ornamental, and fruit crops in southern and eastern Asia, Miami, Florida on Capsicum spp. from St. Vincent and the Africa and Oceania (Ananthakrishnan, 1993; CABI/EPPO, Grenadines, West Indies. This was the first interception at 1997; CABI, 2003). Plants in 112 taxa are reported to be a US port of this thrips on a shipment originating in the hosts of S. dorsalis. It is abundant on chillies in India the Western Hemisphere. In addition, Skarlinsky (2003) (Ramakrishna Ayyar, 1932; Ramakrishna Ayyar and found established S. dorsalis on pepper at several sites Subbiah, 1935), on sacred lotus in Thailand (Mound and in St. Vincent. Subsequently, we found this species to Palmer, 1981), and a serious pest of Arachis (Amin, 1979, be established also on St. Lucia, and we undertook to 1980). In Japan, S. dorsalis is a pest of tea and citrus (Kodomari, 1978). Among the economically important ÃCorresponding author. Tel.: +1 305 246 7001x260; hosts of this pest listed by Venette and Davis (2004) are fax: +1 305 246 7003. banana, bean, cashew, castor, corn, citrus, cocoa, cotton, E-mail addresses: [email protected]fl.edu, DRSeal@ifas.fl.edu (D.R. Seal). eggplant, grapes, kiwi, litchi, longan, mango, melon, onion,

0261-2194/$ - see front matter r 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.cropro.2005.12.008 ARTICLE IN PRESS 950 D.R. Seal et al. / Crop Protection 25 (2006) 949–955 passion fruit, peach, peanut, pepper, poplar, rose, sacara, ranges from about 1500 mm on the southeast coast to soybean, strawberry, sweet potato, tea, tobacco, tomato, about 3800 mm in the interior mountains (http://www.bri- and wild yams (Dioscorea spp.). One or more S. dorsalis life tannica.com). Vegetable and fruit crops are produced year stages occur on all above-the-ground plant parts of its round for domestic consumption and export. Thrips palmi hosts, and causes scarring damage due to its feeding Karny is a significant pest of vegetable crops in St. Vincent (Chang et al., 1995). during the dry season. Frankliniella spp. and Microcepha- The Florida Nurserymen and Growers Association lothrips spp. were also present (Chu et al., 2006). considers S. dorsalis as one of the 13 most dangerous Here we report on the comparative effectiveness of exotic pest threats to the industry (FNGA (Florida various insecticides against S. dorsalis and on their effects Nurserymen & Growers Association), 2003). Venette and on a possible predator of this pest, Cryptolaemus sp. Davis (2004) projected the potential geographic distribu- Elsewhere, we reported on the within pepper plant and tion of S. dorsalis in North America to extend from within pepper field distribution of S. dorsalis (Seal et al., southern Florida to north of the Canadian boundary, as 2006). well as to Puerto Rico and the entire Caribbean region, but Meissner et al. (2005) suggest that the pest is likely to 2. Materials and methods establish in the USA only in the southern and Pacific states, but not overwinter outdoors in northern states. In any case, Five studies were conducted to determine the effective- these projections suggest that this pest could also become ness of various insecticides in controlling S. dorsalis on widely established in South America and Central America. ‘Scotch Bonnet’ pepper on St. Vincent. Three studies In October 2005, this pest was found on potted roses sold (studies 1, 2 and 3) were conducted on Williams Farms, in retail outlets from the Florida Keys to Tallahassee Georgetown, St. Vincent in October 2004 (rainy season). (Hodges et al., 2005), and in November 2005 on pepper Subsequently, in March 2005 study 4 was conducted on seedlings in retail outlets in the Rio Grande Valley but not Williams Farms and study 5 on Baptiste Farms. To outdoors (M.A. Ciomperlik, e-mail 11/16/2005). S. dorsalis conduct these studies, ‘Scotch Bonnet’ pepper was planted is a vector of various viral and bacterial diseases. It into a deep soil without use of plastic mulch. Each field was transmits peanut bud necrosis virus (PBNV), peanut yellow ca. 0.3 ha. The plants were spaced 91 cm within rows and spot virus (PYSV), peanut chlorotic fan-spot virus (PCFV), 122 cm between rows. Plants were maintained using tobacco streak virus (TSV), and acacia bunchy top virus standard cultural practices recommended for St. Vincent. bud necrosis disease, and the bacterial leaf spot bacterium Plants were treated with Manzate and Bravo fungicides at (Amin et al., 1981; Ananthadrishnan, 1993; Mound, 1996; 7–10 day intervals. Each study was initiated 2–3 months Mound and Palmer, 1981). after planting the crop. Detection and identification of S. dorsalis are key in In studies 1 and 2, insecticides were applied alone. In developing management practices (Lewis, 1997). Various study 3, insecticides were applied in combination with the methods have been used employed by entomologists to surfactant sticker, Nu-Film 17TM, at 0.125% V/V. In each determine the presence of S. dorsalis. Bagle (1993) study, treatment plots consisted of a segment of a row dislodged thrips from five young shoots per single plant 456 cm long and 122 cm wide. Treatments in these studies onto a black cardboard and counted them. Likewise, were (1) spinosad (511 ml ha1; Spintor TM2SC, Dow Gowda et al. (1979) shook inflorescences over black paper Agrosciences, Indianapolis, IN); (2) imidacloprid to obtain and count nymph and adult thrips. Suwanbutr et (274 ml ha1; Provados 1.6F; Bayer CropScience, Re- al. (1992) rinsed thrips from plant material using 70% search Triangle Park, NC); (3) chlorfenapyr (731 ml ha1; ethanol and counted individuals collected on a fine muslin Alert 2F, BASF Corporation, Research Triangle Park, sieve. Takagi (1978) constructed a suction trap to monitor NC); (4) novaluron (731 ml ha1; Diamond 0.83 SC; the flight of S. dorsalis and other tea pests. Okada and Crompton Crop Protection, Middlebury, CT); (5) aba- Kudo (1982) used a similar suction trap for monitoring mectin (731 ml ha1; Agrimek 0.15EC; Syngenta Crop flight behavior of S. dorsalis and other thrips. Saxena et al. Production, Inc., Greensboro, NC); (6) azadirachtin (1996) reported that S. dorsalis were attracted to white (511 ml ha1; Neemix 4.5, Certis USA LLC, Columbia, sticky traps. Adults may also be attracted to yellowish- MD); and (7) a nontreated control. In each study, green, green or yellow boards (Tsuchiya et al., 1995). Chu treatments were arranged in a randomized complete block et al. (2006) evaluated the effectiveness of a non-sticky trap design with four replications. Treatments were applied illuminated with a light-emitting diode in capturing S. using an hydraulic backpack sprayer with one BEXR F dorsalis and other thrips. Series flat spray nozzle delivering 2 l min1 at 206.8 kPa. St. Vincent is a volcanic island located at latitude Treatments were evaluated 24 h after each application by 131150N and longitude 611120W within the Windward collecting at random five growing tips per plot, one tip per Islands chain in the eastern Caribbean. Temperatures plant, each consisting of three young leaves. The samples fluctuate between 18 and 32 1C on the coast, the dry season were placed individually in a ziplock bag and taken to the extends from December to May, the rainy season from laboratory for further study. Leaves were washed with June to November, and the island’s average annual rainfall 70% ethanol to separate thrips from leaves. Identifications ARTICLE IN PRESS D.R. Seal et al. / Crop Protection 25 (2006) 949–955 951 of adult and larval thrips were based on the morphology of 3. Results and discussion adult and larval forms and their identities were confirmed with recent taxonomic keys (Mound and Kibby, 1998). In the first study in 2004, all insecticides significantly Adults of S. dorsalis were distinguished from other thrips reduced S. dorsalis adults ðP40:05Þ 24 h after the first based on body transparency, body color, and a dark application when compared with the nontreated control cuticular thickening medially on tergites III to VII. Tergites (F ¼ 4:79; df ¼ 6; 21; Po0.05) (Table 1). First and second of adults are furnished with three discal setae in the lateral instar larvae were also significantly reduced by the various microtrichial fields (Mound and Kibby, 1998). Also, the insecticide treatments (first instar: F ¼ 9:84; df ¼ 6:21; forewing cilia are straight. The larvae of S. dorsalis were Po0.05; second instar: (F ¼ 6:93; df ¼ 6:21; Po0.05)). separated from those of other thrips species based on color S. dorsalis populations increased thereafter in all treat- and size, and confirmed by observing funnel shaped setae ments. At 96 h after the first application, the mean number on the head and abdominal segment IX. of adults appeared to be the lowest on chlorfenapyr (Alert) In 2005, on both farms pepper plants were grown in soil and imidacloprid treated plants, and they were significantly covered with plastic mulch and irrigated using drip tubes lower than on nontreated plants (F ¼ 4:20; df ¼ 6:21; on as needed basis. All other cultural practices were as in Po0.05) (Table 1). However, the level of suppression by previous studies. Treatments evaluated on Williams Farms chlorfenapyr (Alert) and imidacloprid did not differ were (1) three rates of chlorfenapyr (438, 585, 731 ml ha1, significantly from that of novaluron and of abamectin. Pylons 2F; BASF Corporation, Research Triangle Park, However, only chlorfenapyr had suppressed the density of NC); (2) spinosad (511 ml ha1; SpintorTM 2SC); (3) first instars significantly when compared with the non- s imidacloprid (274 ml ha1; Provado 1.6F); (4) abamectin treated control (F ¼ 4:82; df ¼ 6; 21; Po0.05). The density (731 ml ha1; Agrimek 0.15EC); (5) spiromesifen of first instars had increased in the other treatments and (621 ml ha1; Oberons 2 SC; Bayer CropScience, Research these did not differ from the nontreated control. All Triangle Park, NC); (6) cyfluthrin (274 ml ha1; Bay- insecticide treatments had suppressed populations of the throids 2, Bayer CropScience, Research Triangle Park, second instars to levels significantly lower than the NC); (8) methiocarb (1169 ml ha1; Mesurol 75-W; AM- nontreated control (F ¼ 7:61; df ¼ 6; 21; Po0.05). When VAC Chemical Corporation); and (9) a nontreated check. densities of all life stages are considered together, All other materials and procedures were as in the 2004 chlorfenapyr (Alert) provided the highest reduction of studies. In Baptiste Farms, in addition to all treatments S. dorsalis followed by spinosad, imidacloprid, abamectin, used in Williams Farms, chlorfenapyr (731 ml ha1; Alert); novaluron, and azadirachtin (F ¼ 7:61; df ¼ 6; 21; and methiocarb (1169 ml ha1; Mesurol 75-W; AMVAC Po0.05). Chemical Corporation) were evaluated. In the second study in 2004 (field 2), S. dorsalis population densities prior to insecticide applications did 2.1. Statistical analysis not differ significantly (Table 2). However, at 24 h after the first application (Table 2), the mean numbers of Data on the effectiveness of various insecticides were S. dorsalis adults were significantly lower on chlorfenapyr analyzed using software provided by Statistical Analysis (Alert)-treated plants followed by those on abamectin- System (release 6.03, SAS Institute Inc. Cary, NC; SAS treated plants than on the nontreated plants (F ¼ 4:00; Institute, 1988). General linear model procedures were used df ¼ 6; 21; Po0.05) (Table 2). Suppression of adults by to perform the analysis of variance. Means were separated spinosad was not significantly greater than by novaluron. with the Duncan Multiple Range Test (DMRT). The mean numbers of adults in other treatments did

Table 1 Mean numbers of S. dorsalis on pepper plants treated once with various insecticides in ﬁeld 1 of Williams Farms at 24 and 96 h after application in October 2004 (rainy season)

Treatments Rate (ml ha1) Mean numbers of S. dorsalis at 24 h after application of Mean numbers of S. dorsalis at 96 h after application of insecticides insecticides

Adults Small larvae Large larvae Adults Small larvae Large larvae

Spinosad 511 0.50bc 0.00b 0.50b 3.75ab 8.50b 2.00b Imidacloprid 274 1.50bc 0.25b 0.25b 0.50c 16.00ab 1.50b Chlorfenapyr 731 0.00c 0.25b 0.50b 0.25c 0.00c 0.00b (Alert) Novaluron 731 2.50b 0.00b 1.00b 1.50a–c 27.50ab 3.75b Abamectin 731 1.50bc 0.00b 0.25b 1.25bc 25.50ab 2.25b Azadirachtin 511 2.50b 0.50b 1.75b 5.25a 43.75a 10.75b Control 6.25a 3.75a 6.00a 4.50a 22.75ab 21.00a

Means within a column followed by the same letter do not differ signiﬁcantly (P40:05; DMRT). ARTICLE IN PRESS 952 D.R. Seal et al. / Crop Protection 25 (2006) 949–955

Table 2 Mean numbers of S. dorsalis on pepper plants before the application of insecticides in ﬁeld 2 of Williams Farms in October 2004 (rainy season)

Treatments Rate (ml ha1) Before insecticide application At 24 h after ﬁrst application At 24 h after second application

Adults Larvae Total Adults Small Large Total Adults Larvae Total larvae larvae larvae

Spinosad 511 2.00 13.00 15.00 2.00ab 5.00c–e 0.50bc 5.50bc 0.75b 0.50c 1.25bc Imidacloprid 274 4.50 10.25 14.75 4.50a 0.50de 2.50bc 3.00bc 0.33b 0.00c 0.33c Chlorfenapyr (Alert) 731 2.50 8.50 11.00 0.25b 0.00e 0.00c 0.00c 0.00b 0.00c 0.00c Novaluron 731 3.75 8.00 11.75 1.50ab 27.50ab 3.75a–c 31.25a–c 1.50b 1.50bc 3.00bc Abamectin 731 5.50 10.75 16.25 1.25b 25.50a–c 2.25bc 27.75bc 0.25b 0.50c 0.75bc Azadirachtin 511 2.75 10.00 12.75 5.25a 43.75a 10.75a 54.50a 0.75b 5.00b 5.75b Control 4.76 9.75 14.50 4.50a 7.75b–d 5.00ab 12.75ab 4.75a 16.75a 21.50a

No Nu-Film-17TM surfactant-sticker was used in the formulations. Means within a column followed by the same or no letter do not differ signiﬁcantly (P40:05; DMRT).

not differ significantly from the nontreated control. Table 3 The mean numbers of first and second instars were Mean numbers of S. dorsalis on pepper plants treated once with various TM significantly fewer in chlorfenapyr treated plants than in insecticides+Nu-Film-17 surfactant-sticker in field 2 of Williams Farms at 24 and 96 h after application in October 2004 (rainy season) the control (first instar: F ¼ 4:68; df ¼ 6; 21; Po0.05; second instar: F ¼ 3:11; df ¼ 6; 21; Po0.05). Suppres- Treatments Rate At 24 h after second of two sion of first and second instars by the other insecticides (ml ha1) applications 4 days apart did not differ statistically from the control. When im- Adults Larvae Total pacts on adults and larvae were considered together, chlorfenapyr appeared to be the most effective and it Spinosad 511 0.00b 0.00c 0.00c significantly reduced the S. dorsalis population com- Imidacloprid 274 0.25b 0.00c 0.25c pared with the control (F ¼ 5:61; df ¼ 6; 21; P 0.05). Chlorfenapyr (Alert) 731 0.00b 0.00c 0.00c o Novaluron 731 0.75b 4.75b 5.50b Spinosad and imidacloprid were similarly effective and Abamectin 731 0.00b 0.00c 0.00c their effects were not statistically different from those of Azadirachtin 511 2.25a 11.50a 13.75a chlorfenapyr. The effects of novaluron and azadirachtin Control 2.00a 18.00a 20.00a did not differ from the control. At 24 h after the second Means within a column followed by the same letter do not differ application of the insecticides, made 4 days after the first significantly (P40:05; DMRT). application, S. dorsalis adults (F ¼ 2:25; df ¼ 6; 21; Po0.05) and larvae (F ¼ 11:96; df ¼ 6; 21; Po0.05) were significantly lower in all treatments than in the control In the fourth study (Table 4) conducted in March 2005 (F ¼ 2:25; df ¼ 6; 21; Po0.05) (Table 2). Thus, all (rainy season), the mean numbers of S. dorsalis adults after insecticides after two consecutive applications sepa- the first application were significantly fewer in the rated by 4 days effectively reduced S. dorsalis popula- chlorfenapyr (585 and 731 ml ha1), spinosad, imidaclo- tions compared with the control (F ¼ 9:67; df ¼ 6; 21; prid, and abamectin treatments, but not in other treat- Po0.05). ments, than in the control (March 24: F ¼ 3:63; df ¼ 8; 18; In the third study all insecticides in combination with Po0.05). After the second application in all treatments NuFilm-7, except azadirachtin, significantly reduced S. and in the control, the mean numbers of adults had dorsalis adults (F ¼ 9:94; df ¼ 6; 21; Po0.05) and larvae increased from the number present after the first applica- (F ¼ 18:78; df ¼ 6; 21; Po0.05) when compared with the tion. This increase may have been caused by infiltration of control (Table 3). The effect of the addition of NuFilm-17 adults from nearby nontreated pepper plants. In any case, on the effectiveness of the insecticides (Table 3)as the mean numbers of adults were significantly lower in the compared to their effectiveness without the surfactant chlorfenapyr (731 ml ha1), spinosad, and imidacloprid (Table 2) indicates that NuFilm-17 caused a marginal treatments than in the control, but not so for abamectin, improvement in the effectiveness of spinosad, imidacloprid, spiromesifen nor cyfluthrin (March 29: F ¼ 3:35; and abamectin, but not in that of novaluron. No rainfall df ¼ 8; 18; Po0.05) (Table 4). After the first application, occurred during this trial. Also, it is likely that a nonionic mean numbers of larvae were significantly lower in the surfactant would enhance insecticidal effectiveness by imidacloprid treatment than in the control (F ¼ 1:63; increasing the deposition and retention of the delivered df ¼ 8; 18; Po0.05) (Table 4). The other treatments insecticidal formulation and by increasing the wetting of did not suppress the larvae significantly. However, after the plant cuticle especially on plants with trichomes the second application on March 29 (Table 4), chlorfena- (McCloskey, 2003). pyr at 438 and 731 ml ha1, spinosad, imidacloprid, and ARTICLE IN PRESS D.R. Seal et al. / Crop Protection 25 (2006) 949–955 953

Table 4 Mean numbers of S. dorsalis adults and larvae on pepper plants treated with various insecticides on Williams Farms and Baptiste Farms in March 2005 (dry season) at 24 h after the second of two insecticide applications 4 days apart

Treatments Rate (ml ha1) Mean numbers at Williams Farms Mean numbers at Baptiste Farms

Adults Larvae Adults Larvae

March 24 March 29 March 24 March 29 March 26 March 30 March 26 March 30

Chlorfenapyr (Pylons 2F) 731 1.00bc 1.33b 4.33a 0.00b 2.00bc 0.25bc 1.00e 0.50d Chlorfenapyr (Pylons 2F) 585 0.67bc 4.33ab 1.67ab 6.00ab 2.75bc 0.25bc 11.25b–d 4.50cd Chlorfenapyr (Pylons 2F) 438 1.67ab 2.00ab 2.00ab 0.00b 3.75b 0.75bc 7.00d 10.00bc Chlorfenapyr (Alert) 731 – – – – 0.00d 0.00c 0.00e 0.50d Spinosad 511 0.00c 0.33b 0.67ab 0.33b 0.75cd 0.75bc 1.00e 0.50d Imidacloprid 274 0.00c 1.33b 0.00b 0.00b 0.50cd 0.50bc 0.25e 0.75d Abamectin 731 0.67bc 2.00ab 0.67ab 0.67b 2.25bc 2.00b 8.00cd 0.75d Spiromesifen 621 1.67ab 8.33a 3.00ab 10.33a 10.00a 10.75a 30.50a 17.25ab Cyﬂuthrin 205 1.67ab 7.33a 1.67ab 6.00ab 11.75a 11.75a 19.00b 20.00a Methiocarb 1169 – – – – 12.00a 8.75a 11.25bc 14.25ab Control 3.00a 7.67a 3.33ab 6.00ab 10.50a 8.50a 17.75b 13.00ab

Means within a column followed by the same letter do not differ signiﬁcantly (P40:05; DMRT).

abamectin significantly reduced larval populations when Table 5 compared with the control (F ¼ 2:89; df ¼ 8; 18; Po0.05). Mean numbers of Cryptolaemus sp. on pepper plants before and after Overall, the various insecticide treatments, except spiro- treatment with various insecticides on Williams Farms in March 2005 mesifen and cyfluthrin, significantly reduced S. dorsalis Treatments Rate Mean numbers of Cryptolaemus populations in ‘Scotch Bonnet’ pepper. (ml ha1) sp. In the fifth study (Table 4) conducted in March 2005 (rainy season), the mean numbers of S. dorsalis adults in Before After spraying spraying the two sampling dates (March 26 and 30) were signifi- s cantly lower for all rates of chlorfenapyr (Pylon ), Alive Alive Dead chlorfenapyr (Alert), spinosad, imidacloprid, and abamec- Chlorfenapyr (Pylons 2F) 731 0.87 0.37c–e 0.10c tin than in the control (March 26: F ¼ 3:13; df ¼ 10; 33; Chlorfenapyr (Pylons 2F) 585 0.77 0.50b–d 0.03c Po0.05; March 30: F ¼ 5:41; df ¼ 10; 33; Po0.05). Chlorfenapyr (Pylons 2F) 438 0.57 0.67a–c 0.07c However, spiromesifen, cyfluthrin, and methiocarb did Spinosad 511 0.63 0.77ab 0.07c not reduce S. dorsalis adults. The effects of the insecticides Imidacloprid 274 0.90 0.03e 4.73a on larval populations were similar to those on adult Abamectin 731 0.57 0.57a–c 0.20c Spiromesifen 621 0.83 0.13de 0.33c populations (March 26: F ¼ 3:24; df ¼ 10; 33; Po0.05; Cyfluthrin 205 0.73 0.10e 0.90b March 30: F ¼ 1:53; df ¼ 10; 33; Po0.05) (Table 4). Control 1.00 1.00a 0.03c The mean numbers of Cryptolaemus sp. adults before the application of insecticides did not differ among treatments Means within a column followed by the same letter do not differ (Table 5). After the first application of insecticides, the significantly (P40:05; DMRT). mean numbers of live Cryptolaemus adults decreased significantly in imidacloprid treated plants followed by cyhalothrin and spiromesifen treated plants. Conversely, Table 6 the mean number of dead adults was significantly higher in Differential toxicity of various insecticides in a laboratory bioassay to imidacloprid treated plants followed by cyhalothrin and Cryptolaemus sp. spiromesifen treated plants than in the nontreated plants. Treatments Rate (ml ha1) % Mortality Toxicity categorya Mean numbers of dead adults in other treatments did not differ significantly from those in the control. In the Chlorfenapyr 731 50 Moderately harmful laboratory bioassay (Table 6), imidacloprid and cyhalo- (Pylon 2F) Spinosad 511 33 Slightly harmful thrin caused 100% mortality of Cryptolaemus adults (Table Imidacloprid 274 100 Very harmful 6), but abamectin spared 33%, chlorfenapyr spared 50% Abamectin 731 67 Significantly harmful and spinosad spared 67%. Cyfluthrin 205 100 Very harmful In conclusion, the insecticide, chlorfenapyr, was the most Control 0 effective in reducing the densities of S. dorsalis adults and Means within a column followed by the same letter do not differ larvae followed by spinosad and imidacloprid. The significantly (P40:05; DMRT). performance of other insecticides in controlling S. dorsalis aToxicity categories are based on those proposed by Hassan (1977). ARTICLE IN PRESS 954 D.R. Seal et al. / Crop Protection 25 (2006) 949–955 populations was somewhat inconsistent. Nevertheless, all Ananthakrishnan, T.N., 1993. Bionomics of thrips. Annu. Rev. Entomol. of the above insecticides when applied repeatedly were 38, 71–92. effective in suppressing of S. dorsalis populations. Addition Bagle, B.G., 1993. Seasonal incidence and control of Scirtothrips dorsalis Hood in pomegranate. Indian J. Entomol. 55, 148–153. of a surfactant improved the performance of the insecti- CABI, 2003. Crop Protection Compendium: Global Module. CABI cides marginally. Spinosad was slightly harmful and Publishing, Wallingford, UK. chlorfenapyr was moderately harmful to Cryptolaemus CABI/EPPO, 1997. Quarantine Pests for Europe, second ed. CABI sp. populations. These studies suggest that a tentative Publishing, Wallingford, UK. management program for S. dorsalis in pepper may be as Chang, N.T., Parkeker, B.L., Skinner, M., Lewis, T., 1995. Major pest thrips in Taiwan. Thrips Biology and Management: Proceedings of the follows. At the beginning of an infestation of S. dorsalis, 1 1993 International Conference on Thysanoptera. Plenum Press, New chlorfenapyr at 438–731 ml ha should be applied fol- York, pp. 105–108. lowed in 4–7 days by an application of spinosad Chu, C.C., Ciomperlik, M.A., Chang, N.-T., Richards, M., Henneberry, (511 ml ha1), or imidacloprid (274 ml ha1), or abamectin T.J., 2006. Developing and evaluating traps for monitoring Scirto- (731 ml ha1). Additional applications of these insecticides thrips dorsalis (Hood). Florida Entomol., in press. may be needed at approximately 7-day intervals. A FNGA (Florida Nurserymen & Growers Association). 2003. The unlucky 13. Report of the Major Nursery Pest & Disease Identification Task nonionic surfactant should be added to improve the Force. Florida Nursery Growers and Landscape Association, Orlando, deposition, retention and spread of the insecticide over Florida, USA, 1p. the foliage and thus ensure its good performance. Unlike Gowda, G., Ramada, E., Reddy, C.V.K., 1979. Scirtothrips dorsalis Thrips palmi Karny, which is a pest only in the dry season (Hood) (Thysanoptera; Terebrantia: Thripidae) a new pest on cashew (Seal, 2001; Seal and Stansly, 2000), S. dorsalis is an (Anacardium occidentale L). Curr. Res. 8, 116–117. Hassan, S.A., 1977. Standardized techniques for testing side-effects of economic pest also during the rainy season. Clearly, a pesticides on beneficial arthropods in the laboratory. Zeit. Pflanzenk- management system needs to be developed for S. dorsalis rankheiten Pflanzenschutz. 84, 158–163. that will take of advantage of natural enemies and retard Hodges, G., Edwards, G.B., Dixon, W., 2005. Chilli thrips Scirtothrips the development of insecticide resistance by rotational use dorsalis Hood (Thysanoptera: Thripidae) A new pest thrips for Florida. of those insecticides with different modes of action Pest Alert.http://www.doacs.state.fl.us/pi/enpp/ento/chillithrips.html. Kodomari, S., 1978. Control of yellow tea thrips, Scirtothrips dorsalis (McCord et al., 2002). Hood, in tea field at east region in Shizuoka prefecture. Tea Res. J. 48, 46–51. Acknowledgments Lewis, T., 1997. Field and laboratory techniques. In: Lewis, T. (Ed.), Thrips as Crop Pests. CAB International, Wallingford, UK, pp. 435–475. We are very grateful to the Plant Quarantine Division, McCloskey, W.B., 2003. Effect of surfactants and adjuvants on Ministry of Agriculture, Industry and Labour, Kingstown, postemergence herbicide efficacy. Department of Plant Sciences, St. Vincent and the Grenadines for the use of laboratory University of Arizona. 51pp. ag.arizona.edu/crops/presentations/ facilities, local transportation, and arrangements with 2003/mccloskey092403.pdf. McCord, E., Price, J.F., Nagle, C.A., 2002. Pesticide mode of action codes growers. This study could not have been accomplished to aid ornamentals growers in developing control programs to manage without the facilitation and encouragement of Mr. pest resistance. Proc. Fla. State Hort. Soc. 115, 130–133. Philmore Isaacs, Chief Agricultural Officer. Also, we are Meissner, H., Lemay, A., Borchert, D., Nietschke, B., Neeley, A., grateful to Mr. Emil Williams and Mr. Lauron Baptiste for Magarey, R., Ciomperlik, M., Brodel, C., Dobbs, T., 2005. Evaluation allowing us to conduct the studies on their farms. Financial of possible pathways of introduction of Scirtothrips dorsalis Hood (Thysanoptera: Thripidae) from the Caribbean into the continental resources and guidance were provided by the Animal and United States. Center for Plant Health Science and Technology, Plant Health Inspection Service, USDA through the USDA-APHIS, Raleigh, North Carolina, 125pp. leadership of Dr. Daniel A. Fieselmann, National Science Mound, L.A., 1996. The Thysanoptera vector species of tospoviruses. In: Program Leader, and Ms. Carolyn T Cohen, Caribbean Kuo, C.G. (Ed.), Tospoviruses and Thrips of Floral and Vegetable Area Director. In addition, financial support was provided Crops. Acta Horticulturae. An International Symposium, Taichung, by the Florida Agricultural Experiment Station and the China. Technical Communications of the International Society of Horticultural Science, vol. 431, pp. 298–309. University of Florida’s Center for Tropical Agriculture. Mound, L.A., Kibby, G., 1998. Thysanoptera: An Identification Guide, We are very grateful for very valuable suggestions received second ed., CABI, Wallingford, 70p. from an anonymous referee. Mound, L.A., Palmer, J.M., 1981. Identification, distribution and host plants of the pest species of Scirtothrips (Thysanoptera: Thripidae). Bull. Entomol. Res. 71, 467–479. References Okada, T., Kudo, I., 1982. Relative abundance of phenology of Thysanoptera in tea fields. Jpn. J. Appl. Entomol. Z. 26, Amin, B.W., 1979. Leaf fall disease of chilly and pepper in Maharashtra, 96–102. India. Pans 25, 131–134. Ramakrishna Ayyar, T.V., 1932. Bionomics of some thrips injurious to Amin, B.W., 1980. Techniques for handling thrips as vectors of tomato cultivated plants in South India. Agriculture and Livestock, Delhi, spotted wilt virus and yellow spot virus of groundnut, Arachis hypogea India, pp. 391–403. L. Occasional Paper. Groundnut Entomol. ICRISAT 80 (2), 1–20. Ramakrishna Ayyar, T.V., Subbiah, M.S., 1935. The leaf curl disease of Amin, P.W., Reddy, D.V.R., Ghanekar, A.M., 1981. Transmission of chillies caused by thrips in the Guntur and Madura tracks. Madras tomato spotted wilt virus, the causal agent of bud necrosis of peanut, Agric. J. 23, 403–410. by Scirtothrips dorsalis and Frankliniella schultzei. Plant Dis. 65, SAS Institute, 1988. SAS/STAT user’s guide, release 6.0 SAS Institute, 663–665. Cary, NC. ARTICLE IN PRESS D.R. Seal et al. / Crop Protection 25 (2006) 949–955 955

Saxena, P., Vijayaraghavan, M.R., Sarbhoy, R.K., Raizada, U., 1996. Suwanbutr, S., Tongklad, C., Uhnchit, W., Thayamanon, P., Witthayar- Pollination and gene flow in chillies with Scirtothrips dorsalis as pollen ug, W., Khewpoompung, P., 1992. A field trial on the efficacy of some vectors. Phytomorphology 46, 317–327. insecticides for controlling thrips attacking pummelo. In: Proceedings Seal, D.R., 2001. Seasonal abundance and distribution of Thrips palmi of the International Symposium on Tropical Fruit: Frontier in Karny (Thysanoptera: Thripidae) in southern Florida. Proc. Fla. Tropical Fruit Research. Pattaya City, Thailand, 20–24 May 1991. Hortic. Soc. 114, 337–342. Acta Hortic. 321, 876–881. Seal, D.R., Stansly, P.A., 2000. Seasonal abundance and within plant Takagi, K., 1978. Trap for monitoring adult parasites of the tea pest. Jpn. distribution of melon thrips (Thysanoptera: Thripidae) on beans in Agric. Res. Q. 12, 99–103. southern Florida. Proc. Fla. Hortic. Soc. 113, 201–205. Tsuchiya, M., Masui, S., Kuboyama, N., 1995. Color attraction of yellow Seal, D.R., Ciomperlik, M., Richards, M.L., Klassen, W., 2006. tea thrips (Scirtothrips dorsalis Hood). Jpn. J. Appl. Entomol. Zool. Distribution of the Chilli thrips, Scirtothrips dorsalis Hood (Thysa- 39, 299–303. noptera: Thripidae), within pepper plants and within pepper fields on Venette, R.C., Davis, E.E., 2004. Chilli thrips/yellow thrips, Scirtothrips St. Vincent. Fla. Entomol., in press. dorsalis Hood (Thysanoptera: Thripidae) Mini Pest Risk Assessment. Skarlinsky, T.L., 2003. Survey of St. Vincent Pepper Fields for Scirtothrips University of Minnesota, St. Paul, MN, USA, 31pp. dorsalis Hood. USDA, APHIS, PPQ. 5 pp.