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Crop Protection 62 (2014) 10e15

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Crop Protection

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Field evaluation of selected botanicals and commercial syntheticinsecticides against Thrips tabaci Lindeman (Thysanoptera: Thripidae)populations and predators in onion field plots

Abdul Khaliq a,b, Azhar Abbas Khan a,*, Muhammad Afzal a, Hafiz Muhammad Tahir c,Abubakar M. Raza a, Arif Muhammad Khan d

aDepartment of Agricultural Entomology, University of Sargodha, Sargodha, Pakistanb Fodder Research Institute, Agriculture Department (Research Wing), Sargodha, PakistancDepartment of Biological Sciences, University of Sargodha, Sargodha, PakistandDepartment of Biotechnology, University of Sargodha, Sargodha, Pakistan

a r t i c l e i n f o

Article history:Received 11 January 2014Received in revised form25 March 2014Accepted 30 March 2014

Keywords:Chemical insecticidesBiopesticidesEco-friendlyIPMonion thrips

* Corresponding author. Tel.: þ92 483703661.E-mail address: azhar512@gmail.com (A.A. Khan).

http://dx.doi.org/10.1016/j.cropro.2014.03.0190261-2194/� 2014 Elsevier Ltd. All rights reserved.

a b s t r a c t

The effectiveness of three botanical insecticides (neem, datura and bitter apple), and three new chem-istry synthetic insecticides (acephate, spirotetramat and spinetoram) against onion thrips (Thrips tabaci)was evaluated in experimental field plots at university of Sargodha, Pakistan. The influence of thesebotanical and chemical insecticides on natural predators and crop yield was simultaneously investigated.All the botanicals and chemical insecticides tested caused significant reductions (45e70%) in thripspopulations; the botanicals gave more than 60% control of thrips, while among chemical insecticides,acephate was found to be the most effective followed by spirotetramat and spinetoram, respectively, andthese insecticides gave better control than the botanicals. The adverse effects of the botanicals onpredator populations were negligible compared to the chemical insecticides. All chemical treatmentsresulted in a significantly higher yield compared to the untreated control. The botanicals and chemicalinsecticides became less effective by 7 days after treatment. Therefore, it is recommended that treatmentwith botanical or chemical insecticides should be repeated weekly consecutively at least three times tokeep thrips populations below economic injury levels until crop maturity.

� 2014 Elsevier Ltd. All rights reserved.

1. Introduction

Onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae),is a key foliage-feeding pest of onion worldwide (Lewis, 1997;Smith et al., 2011). Immature stages of T. tabaci prefer living in thecentral leaves of the plant, reducing their photosynthetic ability(Jensen et al., 2003). The infested leaves become wrinkled andsilvery in appearance; yield losses due to thrips may range from 18to 60% (Waiganjo, 2004). This pest also causes significant reduction(28e73%) in the bulb size (Fournier et al., 1995; Childers, 1997;Jensen et al., 2002). If the crop is attacked by T. tabaci in its earlygrowth stages, the yield loss may reach 90% (Anonymous, 1984). T.tabaci has a wide range of hosts and its populations switch fromone crop to another in search of suitable hosts (Ibrahim andAdesiyun, 2010a). Therefore, attacks by onion thrips are relatively

unpredictable (Gangaloff, 1999). T. tabaci can directly damage thecrop by sucking cell sap, or indirectly serve as a vector of manyserious plant viruses (Jenser et al., 2003; Thungrabeab et al., 2006;Whitfield et al., 2005).

In Pakistan, onion is an important vegetable crop grown inagricultural land areas amounting to nearly 110 thousand hectares(Malik et al., 2003). To improve crop yield and profitability, it isdesirable to introduce sustainable control measures. In this regard,numerous control measures have been practiced for populationmanagement of thrips; however use of chemical insecticides re-mains the major control strategy.

The frequent use of synthetic chemical insecticides againstthrips can cause development of resistance in the target pop-ulations as well as ecosystem disturbances. It may also lead toinsecticidal residues in onion bulb and mortality or escape of bio-control agents (Shah et al., 2000). The most severe constraint torealizing the potential of natural enemies in field crops is theirdisruption through widespread use of insecticides that have abroad range of toxicity to both pests and their natural enemies

A. Khaliq et al. / Crop Protection 62 (2014) 10e15 11

(Naranjo et al., 2002). Extensive and frequent use of broad spec-trum chemical insecticides in agriculture often leads to the devel-opment of genetically resistant pest populations that are no longeraffected by some commonly used pesticides (Gameel, 2004). Onionthrips populations have been developing resistance against manysynthetic chemical insecticides used for its control (Lebedev et al.,2013). In view of these problems, biodegradable and selectivechemical pesticides can be better alternatives (Raguraman andSing, 1999) and warrant strategic exploration (Hogsette, 1999). Inthis regard, plant-based and new chemistry insecticides haveproven to be effective against targeted pests and also are often saferto ecosystems (Stark and Walter, 1995). At present, some botanicaland new chemistry insecticides are available in the market that arecheap, eco-friendly (safe for the natural predators and parasitoids),and also have minimal adverse effects on human health. In thepresent study, three botanical insecticides (i.e. neem, datura, andbitter apple) and three synthetic insecticides (acephate, spirote-tramat, and spinetoram) were evaluated against T. tabaci pop-ulations in experimental onion field plots. Also, the possibleadverse effects of these botanicals and synthetic chemical in-secticides on populations of naturally occurring predators, such aslady beetles, hoverflies (Syrphidae), and lacewings (Chrysopidae)were investigated.

2. Materials and methods

2.1. Study area and experimental design

The study was conducted at the College of Agriculture, Univer-sity of Sargodha, Sargodha, Punjab, Pakistan during 2010e2011 and2011e2012. For the study, the onion variety Phulkara was raised inthe nursery starting in mid-November. Seedlings (10 weeks of age)were transplanted into experimental field plots in mid-January in2011 and 2012. In total, 21 experimental plots [three for each of sixtreatments (6 � 3¼ 18) and three untreated controls] were utilizedfor each experiment. Each plot was 800 cm long and 90 cmwide. Ineach plot, onion seedlings were planted in three rows with eachrow containing 50 seedlings. The distance between the adjacenttwo young plant rows and between two adjacent plants in each rowwas 30 cm and 15 cm, respectively. A distance of 1.5 m was main-tained between experimental plots to avoid cross contamination byspray draft. The design used was a Randomized Complete BlockDesign (RCBD). Plots were irrigated using canal water on weeklybasis during early three irrigations, while the duration was pro-longed to 10e14 days afterward keeping in consideration the soilcondition. The total required fertilizers were applied in three splitdoses i.e. at sowing, seedling transplantation and onion bulb for-mation time. The recommended doses kg/ha of Nitrogen, Phos-phorus and Potassium at a ratio of 35:35:25 were applied.

2.2. Preparation of insecticidal spray solutions

The solutions of botanicals, neem (Azadirachta indica A. juss)and datura (Datura alba Nees) were prepared according to Khan

Table 1List of chemical insecticides and botanicals and their application rate used in the experim

Chemical insecticides/botanicals Active ingredient/liter of water Actua

Acephate� 75SP acephate 75 g 75%Movento� 240SC spirotetramat 240 g 22.2Radiant� 120SC spinetoram 120 g 11.7Neem azadirachtin 100 g 2%Datura tropane 100 g 2%Bitter apple linoleic acid 100 g 2%

et al. (2013). Fresh fruits of bitter apple (Citrullus colocynthis)were washed, sliced and dried under shade for about one month.Dried fruits were then ground using a blender (Anex-176GL) and100 g of the dried fruit powder was mixed in 1 L of tap water toprepare 10% solution. Detail of the products used and their appli-cation rates are given in the table below:

2.3. Field applications (treatments)

Field applications of the experimental materials were made tothe field plots when the pest populations reached the economicthreshold level (ETL) i.e. 15e20 adults and larvae per plant. Beforethe applications, checks were made to ensure that the pest pop-ulations were equally distributed and were above the economicthreshold level in all experimental plots. . All field treatments weremade with a Champin Poly sprayer (hand-held garden sprayer)with a Turbo T-jet wide-angle spray tip nozzle. The control plotswere sprayed with tap water. Treatments were applied three timesin 2011 (11 March, 2 April, 26 April) and 2012 (6 March, 29 March,23 April).

2.4. Data collection

Samples were collected from plants before treatment (24-h) and3, 7 and 14 days after the last insecticide was applied. Fifteen plantswere randomly selected (5 plants/row) from each experimentalfield plot. The abundance (larvae and adults) of T. tabaci and larvaeof lady beetle hoverfly and lacewing, were estimated using handlens by visually examining leaves until all the insects on eachobserved plant were counted. The Weight of single bulbs (g), yield/plot (kg), and overall yield/hectare (tonnes) from control andtreated plots were also calculated and recorded.

2.5. Data analyses

Data from the two years were combined as no statistically sig-nificant difference was observed between the two years. Normalityof the collected data was determined using a KolmogoroveSimo-nov test. One-way ANOVA followed by Tukey’s test was used tocompare the larval/adult population densities of T. tabaci amongthe experimental field plots. ANOVA was also used to compare theoverall yield of control and experimental plots. The statisticalpackage [SPSS (version16)] was used for the statistical analyses.

3. Results

There were no significant pre-treatment differences in T. tabacinumbers during both years of observation [F ¼ 0.49; P ¼ 0.8; df6,14for 2011; and F ¼ 0.32; P ¼ 0.16; df6,14 for 2012] (Table 1). However,3 days post-treatment, density of T. tabaci in control plots wassignificantly higher (F ¼ 56; P < 0.001; df6,14 for 2011; and F ¼ 63;P < 0.001; df6,14 for 2012) compared to all treated plots. Results ofthe Tukey’s test showed that although all treated plots differed inthe thrips densities compared to control plots, the difference

ental field plots.

l concentration Application rate/liter of water Manufacturer

2.5 g Sun Crop3% 1.25 ml Bayer Crop Science0% 0.4 ml Dow Agro Sciences

20.0 ml n/a20.0 ml n/a20.0 ml n/a

Table 2Differences of thrips density per plant at 24 h pre-treatment and 3, 7, and 14 days after treatments (DAT) using synthetic chemical insecticides and botanicals.

Treatments Pre-treatment 3 7 14

2011 2012 2011 2012 2011 2012 2011 2012

1st ApplicationControl 19.71 � 2.36a 17.37 � 2.41a 21.10 � 2.26b 20.61 � 2.76b 21.93 � 2.60e 26.86 � 3.50e 29.99 � 1.62c 33.92 � 1.44c

Acephate 15.12 � 2.16a 16.64 � 1.97a 2.44 � 0.72a 2.86 � 0.82a 1.86 � 1.09c 1.72 � 1.26c 7.09 � 1.54b 5.61 � 1.94b

Spinetoram 16.64 � 1.17a 18.03 � 1.23a 3.20 � 0.83a 3.10 � 0.73a 2.60 � 0.98d 1.92 � 0.67d 9.05 � 1.82b 5.39 � 1.35b

Spirotetramat 18.16 � 1.82a 15.43 � 1.62a 3.00 � 0.54a 2.92 � 0.64a 1.96 � 0.95c 2.52 � 0.84c 8.80 � 0.99b 6.46 � 1.29b

Neem 17.53 � 2.28a 16.60 � 2.47a 6.17 � 1.35a 6.10 � 1.41a 5.20 � 1.30b 6.05 � 1.40b 13.26 � 1.12a 9.95 � 1.88a

Datura 15.80 � 2.23a 18.16 � 3.19a 5.93 � 1.78a 5.61 � 1.24a 5.93 � 0.11b 5.99 � 0.59b 11.30 � 1.34a 10.66 � 2.14a

Bitter apple 16.18 � 2.00a 17.08 � 1.90a 6.30 � 2.09a 7.10 � 1.99a 6.53 � 1.02a 8.08 � 1.41a 13.91 � 2.46a 11.70 � 2.01a

2nd ApplicationControl 33.50 � 2.05c 40.14 � 1.14c 36.36 � 1.35c 42.54 � 3.13c 46.65 � 6.41c 58.13 � 5.21c 57.13 � 3.48c 64.35 � 4.78c

Acephate 15.06 � 1.25a 14.74 � 1.62a 1.97 � 0.52a 3.1 � 0.47a 4.11 � 1.58a 2.19 � 0.98a 9.00 � 1.36a 6.83 � 1.12a

Spinetoram 13.16 � 1.20a 15.52 � 1.41a 2.77 � 0.44a 3.05 � 0.62a 5.34 � 0.78a 2.56 � 0.83a 9.00 � 1.95a 5.97 � 1.63a

Spirotetramat 14.86 � 0.97a 15.44 � 2.17a 2.67 � 0.72a 2.92 � 0.62a 5.22 � 0.88a 2.74 � 0.74a 10.66 � 0.76a 6.61 � 1.06a

Neem 18.10 � 1.22a 19.98 � 1.62a 6.77 � 0.85b 7.79 � 1.15b 7.68 � 2.60b 6.61 � 2.3b 14.67 � 0.87b 12.84 � 2.03b

Datura 20.83 � 1.64b 17.66 � 1.89b 7.37 � 1.36b 7.02 � 1.61b 8.16 � 0.2.85b 6.64 � 1.74b 14.76 � 0.76b 12.35 � 1.32b

Bitter apple 20.40 � 0.85b 20.45 � 2.53b 7.92 � 0.90b 8.06 � 0.87b 9.18 � 2.54b 7.80 � 1.61b 16.48 � 0.73b 13.02 � 0.93b

3rd ApplicationControl 62.78 � 4.07b 75.60 � 6.13b 68.00 � 2.9c 76.53 � 5.91c 73.95 � 3.65c 80.60 � 4.41c 78.43 � 3.88c 92.23 � 5.17c

Acephate 16.00 � 2.00a 14.70 � 1.44a 3.16 � 0.39a 3.20 � 0.46a 4.84 � 1.04a 2.26 � 0.23a 8.03 � 0.85a 7.1 � 0.81a

Spinetoram 15.55 � 2.69a 14.03 � 2.74a 3.67 � 0.26a 3.43 � 0.76a 5.45 � 0.24a 3.06 � 0.36a 9.1 � 1.35a 6.44 � 1.12a

Spirotetramat 16.56 � 2.39a 16.40 � 2.14a 3.45 � 0.65a 33.40 � 2.55a 5.36 � 0.18a 2.96 � 0.51a 8.86 � 1.67a 7.76 � 1.56a

Neem 19.67 � 2.17a 20.50 � 2.64a 7.65 � 1.06b 8.43 � 1.46b 10.06 � 1.23b 7.89 � 1.64b 12.51 � 0.85a 13.30 � 1.33a

Datura 20.34 � 1.57a 22.36 � 2.17a 7.80 � 0.4b 9.12 � 1.41b 8.78 � 0.47b 9.12 � 1.97b 11.99 � 0.65a 13.03 � 1.24a

Bitter apple 20.63 � 1.30a 20.90 � 3.11a 8.04 � 1.32b 9.03 � 1.72b 11.02 � 2.87b 10.57 � 2.36b 14.76 � 0.77b 13.26 � 1.41b

Note: Values in columns have different superscripts are significantly different.

A. Khaliq et al. / Crop Protection 62 (2014) 10e1512

amongst all treated plots was not statistically significant (Table 2).The lowest density of thrips post-treatment was recorded in theacephate treated plots, followed by spirotetramat, and spinetoramtreated plots.

Statistically significant differences (F ¼ 33.60; P < 0.001; df6,14for 2011; and F ¼ 41.10; P < 0.001; df6,14 for 2012) in densities ofT. tabaci between control and treated plots was observed at 3 dayspost-treatment. Results of the Tukey’s test showed that at 7 dayspost-treatment, population trends of thrips in the treated andcontrol plots were similar to the ones observed at 3 days post-treatment but the densities of thrips were much lower comparedto those at 3 days post-treatment. The Tukey’s tests furtherrevealed that population densities of thrips in the acephate treatedplots not only differed from the control plots but also with all othertreated plots, with the exception of spirotetramat treated plots.Densities of thrips increased after 14 days of treatment in all plots(Table 2). After the 2nd and 3rd rounds of pesticide treatment, thegeneral trend of thrips densities amongst experimental plots wassame as after the 1st treatment (Table 2).

Significantly higher weights of single bulbs compared to con-trols (F ¼ 11.04; P < 0.001; df6,14 for 2011; and df6,14; F ¼ 13.21;P< 0.001; df6,14 for 2012) was noted in all treated plots. The highestbulbs weights were recorded in the acephate treated plots (Table 3).Results of the Tukey’s test showed that the weight of single bulbsamongst different treatments was not statistically significant

Table 3Effects of different treatments (botanicals and chemical insecticides) on single bulb weig

Treatments Overall mean number of thrips density (OMTD) Single bulb weig

2011 2012 2011

Control 23.80 � 2.31a 24.69 � 3.63a 46.12 � 4.01a

Acephate 6.25 � 3.01b 6.94 � 3.39b 73.25 � 3.01b

Spinetoram 7.16 � 3.16b 7.11 � 3.71b 69.09 � 3.60b

Spirotetramat 7.46 � 3.71b 6.94�3b 71.73 � 4.8b

Neem 9.93 � 2.81b 9.69 � 2.48b 63.60 � 2.42b

Datura 9.29 � 2.33b 10.11 � 2.92b 65.04 � 2.46b

Bitter apple 9.94 � 2.32b 11.01 � 2.25b 62.18 � 0.23b

Note: Values in columns having different superscripts are significantly different.

(Table 3). Comparison of two years data revealed a significant dif-ference (F ¼ 12.90; P ¼ 0.001; df1,28). Similar trends were observedin yield/plot (F ¼ 9.98; P < 0.001; df6,14 for 2011; andF ¼ 13.19;P < 0.001; df6,14 for 2012) and for the two years datacomparison [F ¼ 9.25; P ¼ 0.005; df1,28 (Table 3)] as well as foryield/hectare (F ¼ 9.97; P < 0.001; df6,14 for 2011; df6,14; F ¼ 13.2;P < 0.001 df6,14 for 2012 and F ¼ 9.21; P ¼ 0.006; df1,28) for the twoyears data comparison (Table 3)]. The population density of T. tabaciwas found to be strongly negatively correlated with the weight of asingle bulb, yield/plot, and yield/hectare (R ¼ �0.95, P < 0.001).

Acephate adversely affected populations of lady beetles, hov-erflies and lacewings (Fig. 1-A,B,C) more drastically than the othernew chemistries and botanicals. Overall, there was a significantdifference between densities of lady beetles (F¼ 506.67; P< 0.001;df6,14), hoverfly flies (F ¼ 175.42; P < 0.001; df6,14), and lacewings(F ¼ 35.91; P < 0.001; df6,14) between treated and untreated plots.However, the post-hoc tests showed that these differenceswere dueto varying effects of the chemical insecticides.

4. Discussion

This study revealed that the tested botanical and chemical in-secticides were highly effective against onion thrips. In the past, theefficacy of plant extracts against insect pests of agricultural cropshas been evaluated by many researchers. For example, Malik et al.

ht yield/plot and total yield/hectare.

ht (g) Yield/plot (kg) Yield/hectare (tones)

2012 2011 2012 2011 2012

39.23 � 1.46a 6.91 � 0.43a 5.88 � 0.14a 9.93 � 0.93a 8.44 � 0.31a

67.69 � 2.95b 10.98 � 0.41b 10.15 � 0.29b 15.75 � 0.89b 14.57 � 0.63b

64.50 � 2.63b 10.36 � 0.34b 9.67 � 0.26b 14.87 � 0.74b 13.88 � 0.56b

66.06 � 3.97b 10.76 � 0.41b 9.90 � 0.39b 15.44 � 0.90b 14.22 � 0.85b

58.44 � 3.89b 9.54 � 0.27b 8.76 � 0.38b 13.69 � 0.58b 12.58 � 0.83b

61.07 � 3.49b 9.75 � 0.27b 9.16 � 0.34b 14.00 � 0.58b 13.14 � 0.75b

57.90 � 3.88b 9.32 � 0.23b 8.68 � 0.38b 13.38 � 0.5b 12.46 � 0.83b

Fig. 1. Effects of botanical and chemical insecticides on the density (per plants) of lady beetles (A), hoverflies (B) and lacewings (C). Data presented as means � SEM.

A. Khaliq et al. / Crop Protection 62 (2014) 10e15 13

(2003) reported 42.7%,17.2% and 6.8% thrips mortality with extractsof milkweed, datura, and bitter apple, respectively. Similarly, Kadriand Goud (2006) recorded significant reductions in onion thripswith neem extracts. Similar results of neem toxicity against thripswere reported by Mishra et al. (2007). In the present study, datura,neem and bitter apple caused more than 60% reductions in pop-ulations of T. tabaci up to 7 days post treatment.

The present study revealed that acephate was most effectivesynthetic insecticide against thrips, followed by spirotetramat andspinetoram. Kadri and Goud (2006) studied the effectiveness of

imidacloprid, emamectin benzoate and acetamiprid against onionthrips and discovered that these insecticides significantly reducedthrips populations. Waters and Walsh (2010) found that spine-toram was effective against onion thrips; however, only spirote-tramat provided adequate control of thrips. Yasar et al. (2006)investigated the efficacy of four synthetic insecticides, Thunder(dichlorvos), Lorsban (chlorpyrifos), Ripcord (cypermethrin), andLaser� (cypermethrin þ dimethoate) against onion thrips andfound 66.5e93.3% mortality after first round of spray, and 82e92%mortality after the second round. Methamidophos 60 SL was also

A. Khaliq et al. / Crop Protection 62 (2014) 10e1514

found to be highly effective against onion thrips, giving more than80% reduction of the pest.

Hazara et al. (1999) and Sadozai et al. (2009) evaluated theefficacy of lamda cyhalothrin, endosulfan, imidacloprid, and pro-fenophos against thrips and observed 61.6, 86.6, 51.2, and 97.6%mortalities of the pest, respectively, three days after insecticidalapplication. Mandi and Senapati (2009) reported that acetamipridand thiamethoxam were the most effective in controlling thripsinfestation, giving 93.3% and 89.9% control, respectively, whereasneem-based pesticides and Bacillus thuringiensis microbial pesti-cide caused 54.2% and 43.4% thrips reduction, respectively. Naultet al. (2012) observed that the field plots treated with spine-toram had lower thrips larval population densities compared tothe plots treated with spirotetramat, but these differences werestatistically not significant. Subramanian et al. (2010) evaluatedthe efficacy of chemical insecticides and botanicals against thripsand reported that all tested synthetic insecticides and botanicalswere effective.

The present study showed that onion yield/hectare was signif-icantly higher in the plots treatedwith chemical insecticides as wellas botanicals compared to controls during both study years(Table 3). Neem extract can increase the yield of onions by up to13.8% (Mishra et al., 2007). Similar results were reported byFarmanullah et al. (2010) while testing endosulfan, imidacloprid,spinosad, and acetamiprid against thrips. Jensen et al. (2003)recorded 4e27% onion yield reduction due to insect attack, whileIbrahim and Adesiyun (2010b) reported 40% increase in onion yieldwhen crop was managed through the use of pesticides. Kisha(1977) indicated that light infestations of thrips can cause 39%yield losses while in the case of severe thrips infestation, 57% onionyield reduction can occur. High yield loss (41%) was also observedby Raheja (1973) due to attack of thrips in onion plots. Uvah (1984)reported up to 32% increase in onion yield when treated with in-secticides as compared to control. Sometimes severe thrips infes-tation can cause 66% onion yield loss (Reuda and Shelton, 2000).

Hoelmer et al. (1990) discovered that a commercial neeminsecticide was not toxic to adult coccinellid predators. Azadir-achtin (Neemix�) was virtually nontoxic to larvae of Coccinellaseptempunctata (seven-spot ladybird) exposed to direct sprays inthe laboratory (Banken and Stark, 1997). Jones et al. (2005)observed that bacteria- and neem-based insecticides were harm-less to natural predatory fauna. However, Tunca et al. (2012)commented that no pesticide is 100% safe and non-toxic to natu-ral enemies. Nevertheless, the margin of safety for botanical pes-ticides is generally much higher than synthetic chemical pesticides.The results of the present study are in agreement with those ofTunca et al. (2012) reporting that new chemistry insecticides andbotanicals are relatively safe for the natural predators.

To keep populations of T. tabaci in check the use of insecticidesthree times over the cropping season of onion is of high impor-tance. At the same time to have a friendly environment for bene-ficials and human the use of safe chemistries is needed. Botanicalsand selective insecticides can be the alternative toward this pro-cess. The findings of present investigations showed less impact oftreated chemicals on bio-control agents in addition to suppressionof T. tabaci population. Higher yields of onion were obtained fromtreated plots compared to untreated controls.

References

Anonymous, 1984. Annual Report. Associated Agricultural Development Founda-tion, pp. 95e98.

Banken, J.A.O., Stark, J.D., 1997. Stage and age influence on the susceptibility ofCoccinella septempunctata L. (Coleoptera: Coccinellidae) after direct exposure toNeemix, a neem insecticide. J. Econ. Entomol. 90, 1102e1105.

Childers, C.C., 1997. Feeding and oviposition injuries to plants. Thrips as Crop Pests.Lewis, Tedn, CAB International, New York, pp. 505e537.

Farmanullah, Maraj-ul-Mulk, Farid, A., Saeed, M.Q., Sattar, S., 2010. Population dy-namics and chemical control of onion thrips (Thrips tabaci, Lindemann). Pak. J.Zool. 42, 401e406.

Fournier, F., Boivin, G., Stewart, R.K., 1995. Effect of Thrips tabaci (Thysanoptera:Thripidae) on yellow onion yields and economic thresholds for its management.J. Econ. Entomol. 88, 1401e1407.

Gameel, S.M.M., 2004. Eco-Biological studies on the black melon bug, Coridius(Aspongopus) viduatus F. (Hemiptera: Pentatomidae) in the New Valley. Ph.D.Thesis. Faculty of Agriculture, Assiut University, Egypt.

Gangaloff, J.L., 1999. Population dynamics and insecticide resistance of onion thrips,Thrips tabaci L. (Thysanoptera: Thripidae), in onions. Ph.D. Thesis. CornellUniversity, p. 131.

Hazara, A.H., Shakeel, M., Khan, J., Iqbal, M., Khan, S., 1999. Effect of non-chemicalmethods and botanical insecticides on onion thrips. Thrips tabaci Lind, (Thy-sanoptera: Thripidae) in onion crop in Balochistan. Sarhad J. Agric. 15, 619e624.

Hoelmer, K.A., Osborne, L.S., Yokomi, R.K., 1990. Effects of neem extracts on bene-ficial insects in greenhouse culture. In: C. Locke, J., Lawson, R.H. (Eds.), Neem’sPotential in Pest Management Programs, Proc. USDA NeemWorkshop, pp. 100e105. United States Department of Agriculture, Agricultural Research Service,ARS-86, Beltsville.

Hogsette, J.A., 1999. Management of ectoparasites with biological control organ-isms. Int. J. Parasitol. 29, 147e151.

Ibrahim, N.D., Adesiyun, A.A., 2010a. Effects of transplanting dates and insecticidefrequency in the control of Thrips tabaci Lindeman (Thysanoptera: Thripidae) ononion (Allium cepa L.) in Sokoto, Nigeria. J. Agric. Sci. 2, 239e249.

Ibrahim, N.D., Adesiyun, A.A., 2010b. Seasonal abundance of onion thrips, Thripstabaci lindeman in Sokoto, Nigeria. J. Agric. Sci. 2 (1), 107e114.

Jensen, L., Simko, B., Shock, C.C., Saunders, L.D., 2002. Alternative methods forcontrolling onion thrips (Thrips tabaci) in Spanish onions. Oregon State Uni-versity Agricultural Experiment Station Special Report 1038, pp. 104e111.

Jensen, L., Simko, B., Shock, C.C., Saunders, L.D., 2003. A two-year study on alternativemethods for controlling onion thrips (Thrips tabaci L.) in Spanish onions. OregonState University Agricultural Experiment Station Special Report 1048, pp. 94e106.

Jones, T., Scott-Dupree, C., Harris, R., Shipp, L., Harris, B., 2005. The efficacy ofSpinosad against western flower thrips Frankliniella occidentalis, and its impacton associated biological control agents on greenhouse cucumbers in SouthernOntario. Pest Manage. Sci. 61, 179e185.

Kadri, S., Goud, B., 2006. Efficacy of newer molecules of insecticides and botanicalsagainst onion thrips, Thrips tabaci (Lindeman), (Thysanoptera: Thripidae). Kar-nataka J. Agric. Sci. 19, 539e543.

Khan, A.A., Afzal, M., Raza, A.M., Khan, A.M., Iqbal, J., Tahir, H.M., Qureshi, J.A.,Khaliq, A., Zia-ul-Haq, M., Aqeel, M.A., 2013. Toxicity of botanicals and selectiveinsecticides to Asian citrus psylla, Diaphorina citri K. (Homoptera: Psyllidae) inlaboratory conditions. Jokull 63, 52e72.

Kisha, J.S.A., 1977. Cultural and insecticidal control of Thrips tabaci on onions in theSudan. Ann. Appl. Biol. 86, 219e228.

Lebedev, G., Abo-Moch, F., Gafni, G., Ben-Yakir, D., Ghanim, M., 2013. High level ofresistance to spinosad, emamectin benzoate and carbosulfan in populations ofThrips tabaci collected in Israel. Pest Manag. Sci. 69 (2), 274e277 http://dx.doi.org/10.1002/ps.3385.

Lewis, T., 1997. Thrips as crop pests. CAB International, Wallingford, UK, p. 740.Malik, M.F., Nawaz, M., Hafeez, Z., 2003. Efficacy of synthetic insecticides and bo-

tanicals infusions against onion thrips in Balochistan, Pakistan. Asian J. Plant Sci.2 (10), 779e781.

Mandi, N., Senapati, A.K., 2009. Integration of chemical botanical and microbialinsecticides for control of thrips, Scirtothrips dorsalis Hood infesting chili.J. Plant Protec. Sci. 1, 92e95.

Mishra, D.K., Pathak, G., Tailor, R.S., Deshwal, A., 2007. On farm trial: an approach formanagement of thrips in onion. Indian Res. J. Ext. Edu 7, 66e67.

Naranjo, S., Ellswoth, P., Chu, C., Henneberry, T., 2002. Conservation of predatoryarthropods in cotton: role of action thresholds for Bemisia tabaci (Homoptera:Aleyrodidae). J. Econ. Entomol. 95, 682e691.

Nault, B.A., Hsua, C.L., Hoepting, C.A., 2012. Consequences of co-applying in-secticides and fungicides for managing Thrips tabaci (Thysanoptera: Thripidae)on onion. Pest Manag. Sci. http://dx.doi.org/10.1002/ps.3444.

Raguraman, S., Sing, R.P., 1999. Biological effects of neem (Azadirachta indica) seedoil on eggs parasitoid, Trichogramma chilonis. J. Econ. Entomol. 92, 1274e1280.

Raheja, A.K., 1973. Onion Thrips and their control in northern Nigeria. Samaru Agric.Newsl. 15, 82e86.

Reuda, A., Shelton, A.M., 2000. Onion thrips. <http://www.nysaes.cornell.edu/ent/hortcrops/english/thrips.html>. Visited on 25.11.13.

Sadozai, A., Zeb, Q., Iqbal, T., Anwar, S., Badshah, H., Ali, A., Tahir, M., 2009. Testingthe efficacy of different insecticides against onion thrips in Tarnab, Peshawar.Sarhad J. Agric. 25, 269e271.

Shah, Z., Ishrat, S., Ali, R., 2000. Are pesticides friendly to soil microbes? Sarhad.Journal of Agriculture 16 (3), 305e318.

Smith, E.A., Ditommaso, A., Fuchs, M., Shelton, A.M., Nault, B.A., 2011. Weed host foronion thrips (Thysanoptera: Thripidae) and their potential role in the epide-miology of Iris Yellow Spot Virus in an onion ecosystem. Environmental Ento-mology 40 (2), 194e203.

Stark, J.D., Walter, J.F., 1995. Persistence of azadirachtin A and B in soil: effects oftemperature and microbial activity. J. Environ. Sci. Health 30, 685e698.

A. Khaliq et al. / Crop Protection 62 (2014) 10e15 15

Subramanian, S., Muthuswami, M., Krishnan, R., Thangamalar, A., Indumathi, P.,2010. Bioefficacy of botanicals and insecticides against mulberry thrips, Pseu-dodentro thrips mori Niwa. Karnataka J. Agric. Sci. 23, 47e50.

Thungrabeab, M., Peter, B., Cetin, S., 2006. Possibilities for biocontrol of the onionthrips (Thysanoptera: Thripidae) using different entomopathogenic fungi fromThailand. Mitt. Dtsch. Ges. Allg. Angew. Ent. 15, 299e303.

Tunca, H., Kilinçer, N., Ozkan, C., 2012. Side-effects of some botanical insecticidesand extracts on the parasitoid, Venturia canescens (Grav.) (Hymenoptera: Ich-neumonidae). Turk. Entomol. Derg. 36, 205e214.

Uvah, I.I., 1984. Studies on the control of onion thrips, Thrips tabaci L. on irrigatedonion at Zaria. Niger. Entomol. Mag. 4, 74e77.

Waiganjo, M.M., 2004. Studies on the distribution, ecology and preventive man-agement of thrips (Thysanoptera: Thripidae) on Onion in Kenya. PhD Thesis.Kenyatta University.

Waters, T.D., Walsh, D.B., 2010. Onion Thrips control in Washington State. Wash-ington State University, Dept. Entomology, Prosser. http://www.unce.unr.edu/.

Whitfield, A.E., Ullman, D.E., German, T.L., 2005. Tospovirus-thrips interactions.Annu. Rev. Phytopathol. 43, 459e489.

Yasar, Sattar, S., Saeed, M.Q., Anis-ur-Rahman, Usman, A., 2006. Chemical control ofthrips tabaci L. (Thysanoptera: Thripidae) on garlic in Peshawar. Sarhad J. Agric.22, 481e483.