Efficacy of bio-insecticides against thrips, Thrips ...

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ABSTRACT: Field experiment was conducted to determine the effectiveness of five bio-insecticides against onion thrips,. Thrips tabaci on two onion cultivars for ...
Pest Management in Horticultural Ecosystems, Vol. 21, No. 2 pp 180-186 (2015)

Efficacy of bio-insecticides against thrips, Thrips tabaci Lindeman on onion crop MAHER AHMED MORAIET1*, M. SHAFIQ ANSARI2 and SALMAN AHMAD3 1

Department of Plant Protection, Agriculture Research Station–Seiyun, Agricultural Research and Extension Authority, P.Box : 9041 Seiyun, Hadramout, Yemen 2 Department of Plant Protection, Faculty of Agricultural Sciences, Aligarh Muslim, University, Aligarh-202002, India 3 Integral Institute of Agricultural Science and Technology, Integral University, Lucknow, India *E-mail: [email protected] ABSTRACT: Field experiment was conducted to determine the effectiveness of five bio-insecticides against onion thrips, Thrips tabaci on two onion cultivars for two consecutive years (2011/12and 2012/13). Most of the tested bio-insecticides caused significant (P< 0.05) reduction of thrips compared to the control in all the observation dates except 7days after treatment in 2012. Interaction results showed that Lastraw has significantly (P50% in USA (Boateng, 2012). Insecticides are the main option for the management of thrips, but this strategy is inadequate and unsustainable (Maniania et al., 2003), because resistance has been reported to various groups of insecticides (Foster et al., 2010; Herron et al., 2011; Lebedev et al., 2013). Recently, there is an increasing demand for an alternative non-toxic and environmentally friendly management strategies due to negative impact of insecticides on human health and the environment (Visalakshy and Krishnamoorthy, 2012). Entomopathogens were suggested as potential bio-insecticides for management of T. tabaci in onion (Visalakshy and Krishnamoorthy, 2012). Beauveria bassiana and other pathogens were appraised under field condition on onion crop against onion thrips (Visalakshy and Krishnamoorthy, 2012; Pandey et al., 2012). In addition, botanical insecticides were found to be effective on many important horticultural pests including thrips. Neem formulations were also assessed against onion thrips in onion field (Sule et al., 2008; Ahmed and El-Mogy, 2011; Pandey

MATERIALS AND METHODS An experiment was carried out in the field of Faculty of Agricultural Sciences, Aligarh Muslim University, Aligarh, India for two consecutive years (2011/12 and 2012/13). Seeds of two cultivars; Onion White and Onion Kessar were sown in the nursery beds (1×3m) in the mid-October, and standard agronomic practices were adopted for commercial cultivation of onion. Seedlings were then transplanted in the main field in the mid-December with spacing of 15×30 cm with 4 rows (21plants/row) in each plot (1x3 m). One dose of phosphate (P2-O 5) @45 kg/ha was applied at the time of transplanting, and three doses of nitrogen (N) @90 kg/ h were given, where first dose (50%) was at the time of transplanting, second (25%) and third (25%) doses were on 35 and 45 days after transplanting, respectively. 180

Bio-insecticides against Thrips tabaci

The experiment was performed in a randomized complete block design (RCBD) with three replications. At the time of transplanting, the seedlings were treated with thiophorate 70WP @2 gm/L for 20-30 min against root rot. Two criterias i.e., thrips density and marketable yield were selected to determine the effectiveness of bio-insecticides as suggested by is alakshy and Krishnamoorthy (2012). Observations of densities were made 45 days from transplanting on three plants selected randomly from each plot. Randomization was performed in the middle lines with ‘V’ form, and re-selection of the same plant was avoided. Two plants were not selected at the end of middle lines from both sides. Time of observations and an application of bio-insecticides were made between 3:00 to 5:00 pm. The application of bio-insecticides was made 114 and 100 days after transplanting in 2013 and 2014, respectively, when the density of thrips reached the economic threshold level (ETL) i.e. 30 thrips per plant (TP) (Alston and Drost, 2008; Tripathy et al., 2014). Therefore, five treatments and one control “treated with water”, i.e. B. bassiana (108 spores/ml 10.00% w/w) @ 2m/L (Myco-Jaal 10 % SC, Pest control India (PCI) Pvt. Ltd., India), azadirachtin 0.15% w/w @ 2ml/L (Neemarin 1500 ppm, Biotech international Ltd., India), azadirachtin 0.03% w/w @ 2m/ L (Neem Baan 300 ppm, PCI Pvt Ltd), soap @ 10g/3L (Tide, Procter and gamble Co), Lastraw™ 50% @ 5ml/ L (PCI Pvt. Ltd) were applied on two cultivars i.e. against T. tabaci. Hand Compression Sprayer was used to spray the formulations. Density of thrips was estimated 3, 5, and 7 days after treatment (DAT) and expressed as mean±SE. Onion was harvested when 50-60% of canopy fell down 121 days after transplanting. Yield was estimated by weighting of onion produced in one line (middle) per plot then converted to t/ha and expressed as mean±SE. Curing of onion was done for three weeks after harvesting. Statistical Analysis System

(SAS) software program version 9.3.1 (SAS Institute Inc., 2012) was used for analysis of data. A Tukey-HSD test was used for comparing multiple treatments. A benefit-cost ratio (BCR) of bio-insecticides was also calculated on both cultivars.

RESULTS AND DISCUSSION Bio-pesticides can make important contribution to sustainable agriculture that help to reduce reliance of chemical pesticides (Ansari et al., 2013). They can influence the behavior of insects that search for use of plants for their reproduction (Charleston et al., 2006). In the present study, density of thrips (Table 1) was significantly reduced (P0.05) effect was determined between bio-insecticide treatments at 5 and 7 DAT, but significant (P