Development of an effective dose of cypermethrin for managing eggplant shoot and fruit borer (Leucinodes orbonalis)

Transcription

1 International Journal of Biosciences IJB ISSN: (Print) (Online) Vol. 5, No. 9, p , 2014 RESEARCH PAPER OPEN ACCESS Development of an effective dose of cypermethrin for managing eggplant shoot and fruit borer (Leucinodes orbonalis) Shahinoor Rahman 1*, Md. Mahbubar Rahman 2, Md. Zinnatul Alam 2, M. Mofazzal Hossain 3 1 Department of Entomology, EXIM Bank Agricultural University, Bangladesh; 2 Department of Entomology, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur-1706, Bangladesh 3 Department of Horticulture, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur-1706, Bangladesh Key words: Cypermethrin, effectiveness, eggplant shoot and fruit borer (ESFB). Article published on November 20, 2014 Abstract A study was conducted in the experimental farm of Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Gazipur, Bangladesh during November 2012 to April 2013 in order to find out an effective dose of cypermethrin insecticide (that is commonly used in Bangladesh) against Eggplant Shoot and Fruit Borer (ESFB). Including control there were five treatments were used to measure the effectiveness of the particular insecticide based on fruit infestation, total yield and also benefit - cost ratio. Among the different treatments Ripcord (cypermethrin) 10 1 ml/l of water sprayed after observing 5% level of fruit infestation and repetition of the same at 15 days interval (T3) performed the best in respect of marketable yield (30.55 t/ha), reduction of fruit infestation over control (77.54%) and also the benefit cost ratio (8.14). * Corresponding Author: Shahinoor Rahman shahinoor_ent@yahoo.com 354 Rahman et al.

2 Introduction Eggplant (Solanum melongena L.) is one of the popular vegetables widely used by most of the people and is favored by many people of various countries viz., Central, South and South East Asia, some parts of Africa and Central America (Harish et al., 2011). It is native of India and is grown all over Bangladesh (Choudhary, 1970; Pareet, 2006). Eggplant is extensively damaged by the most destructive pest, eggplant fruit and shoot borer (ESFB) (Leucinodes orbonalis) which caused 31-86% fruit damage in Bangladesh (Alam et al., 2003) reaching up to 90%, that making it totally unfit for human consumption. To overcome this loss, different types of insecticides are used by the farmers of Bangladesh and they apply indiscriminately even at fruiting stage (Zafar et al., 2012). A survey of pesticide use in Bangladesh indicated that farmers sprayed chemical insecticides up to 180 times during a cropping season to protect their eggplant crop infested by the eggplant fruit and shoot borer, Leucinodes orbonalis (SUSVEG- Asia, 2007). Different combinations of management packages were used by our Bangladeshi farmer to manage ESFB. The combination of Chlorpyriphos 50% EC + Cypermethrin 5% EC, being the most effective and economically viable insecticide to manage L. orbonalis in eggplant crop (Sharma et al., 2012). Cypermethrin have some important properties, such as greater photo-stability, effectiveness at low concentrations, low environmental persistence, and easy breakdown compared to other group of insecticides. So, it s need to be investigate the effictiveness of cypermethrin singly to control ESFB. Previously in Bangladesh cypermethrin was used as an associate product with other systemic insecticides but not used as sole product. Materials and methods Location A study was conducted in the experimental farm of Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Gazipur, during November 2012 to April Design of Experiment The field experiment comprising of four treatments with an untreated control was laid out in a Randomized Complete Block Design (RCBD) with three replications. The treatments were: T1 (Ripcord (cypermethrin) 10 1 ml/l of water sprayed at 45 DAT and repetition of the same at 7 days interval), T2 (Ripcord (cypermethrin) 10 1 ml/l of water sprayed after initiation of 2% level of fruit infestation and repetition of the same at 15 days interval), T3 (Ripcord (cypermethrin) 10 1 ml/l of water sprayed after observing 5% level of fruit infestation and repetition of the same at 15 days interval), T4 (Ripcord (cypermethrin) 10 2 ml/l of water sprayed after observing 5% level of fruit infestation and repetition of the same at 15 days interval), T5 (Untreated control). Data Recording Data were recorded by counting the infested number of fruit and weight during each harvesting and also measure the total infested yield and fresh yield. For calculating percent fruit infestation, data on the number and weight of healthy, infested and total fruits harvested per plot were recorded at each harvest. Harvesting was done nine times throughout the fruiting season (27 February 2013 to 15 April 2013) at an interval of 5 days. Percent fruit infestation (%) at each such harvest was calculated by using the following formula: So, the present study was undertaken to find out an effective dose of cypermethrin insecticide against ESFB based on fruit infestation, total yield and also benefit - cost ratio. 355 Rahman et al.

3 Data Analysis The collected data were analyzed through MSTAT-C software in single factor RCBD was used to separate means. Results and discussion Effect of Ripcord (cypermethrin) on Fruit Infestation Comparative effectiveness of various treatments on eggplant fruit infestation was evaluated in terms of percent fruit infestation by number and by weight as well as calculated percent reduction of infestation over control. Table 1. Effect of ripcord (cypermethrin) on fruit infestation by eggplant shoot and fruit borer. In a column, means followed by same letter(s) are not statistically different by DMRT at 5% level of significance. Treatments Dose (ml/l of water) Total no. of application *Fruit infestation (%) *Reduction of fruit infestation (%) over control By number By weight By number By weight T d d b b T c c c c T e d a a T b b d d T a a *Mean of 3 replications; each replication is derived from mean of 9 recordings; each recording is made from 5 plants per treatment. The results presented in Table 1 revealed that significantly the lowest fruit infestation by number (12.73%) and weight (10.67%) were observed in T3, whereas the highest value for the same was recorded in T5 (control). It also revealed that fruit infestation by number as well as by weight had the highest fruit infestation reduction over control was recorded in T3 (40.15% and 42.16%, respectively). These were followed by 36.67% (by number) and 38.64% (by weight) in plot treated with T1, and 31.49% (by number) and 33.55% (by weight) in T2 treated plots. The lowest 20.21% (by number) and 20.70% (by weight) was in T4 treated plots. Table 2. Effect of ripcord (cypermethrin) on fruit yield of eggplant. Treatments Dose (ml/l of water) Total no. of application Fruit Yield (t/ha) *Healthy *Infested *Total T c 3.32 bc b T b 3.07 cd a T a 2.12 d a T d 4.40 b b T e 9.44 a b In a column, means followed by same letter(s) are not statistically different by DMRT at 5% level of significance. *Mean of 3 replications; each replication is derived from mean of 9 recordings; each recording is made from 5 plants per treatment. 356 Rahman et al.

4 The results thus obtained in the present study when compared to the findings reported by other workers suggested that all the treatments including the one (T3) which achieved the highest reduction of 42.16% (by weight) and 40.15% (by number) were less effective in reducing the fruit infestation. In a study conducted at BARI, Gazipur during Rabi, ( ), Decis was found to show the highest level of effectiveness and provided 63.31% reduction of fruit infestation over control. Arrivo and Bestox achieved 56.94% and 51.33% reduction in fruit infestation, respectively over control (Anonymous, 1995). Table 3. Effect of ripcord (cypermethrin) on the increase/decrease in fruit yield of eggplant over control. Treatments Dose Total no. of *Healthy Yield *Infested Yield *Total Yield application (t/ha) Increade(+)/ Increade(+)/ Increade(+)/ decrease(-) over (t/ha) decrease(-) over (t/ha) decrease(-) over control (%) control (%) control (%) T c bc b T b cd a T a d a T d b b T e 9.44 a b In a column, means followed by same letter(s) are not statistically different by DMRT at 5% level of significance. *Mean of 3 replications; each replication is derived from mean of 9 recordings; each recording is made from 5 plants per treatment. Effect of Ripcord (cypermethrin) on Fruit Yield of Eggplant Significant effect of different treatments on yield in terms of total fruit yield, healthy fruit yield and infested fruit yield were observed. The results presented in Table 2 showed that the total fruit yield was maximum (32.67 t/ha) in T3 which was statistically similar to that of T2 (32.44 t/ha). The yield of infested fruit was the highest (9.44 t/ha) in untreated control (T5) which was statistically different from all other treatments. This was followed by 4.40 t/ha observed in T4 which was not statistically different from that of T1. The lowest infested fruit (2.12 t/ha) was harvested from T3 and this was statistically similar with that of T2 (3.07 t/ha). the other hand, the lowest yield of healthy fruit was harvested from untreated control (Table 2). A further analysis of the healthy yield data to assess the impact of each treatment on yield over control is presented in Table 3. It can be revealed that T3 ensured the highest increase (40.71%) of healthy fruit yield over control. This was statistically different from all other treatments and this was followed by 35.28% recorded in T2, 29.38% in T1, and 20.95% in T4. On the other hand the highest reduction (77.54%) of infested fruit yield over control was in T3 which was statistically different from all other treatments. Consequently, as a cumulative impact, the highest total fruit yield increase was obtained in T3 (4.84%) followed by 4.10% in T2, 0.80% in T1 treated plots. In case of healthy fruit, the highest yield (30.55 t/ha) of eggplant was obtained from T3 which was statistically different from all other treatments. On The findings of this study support the findings of Islam and Karim (1994) and Naitam and Markad (2003) and they reported that application of 357 Rahman et al.

5 insecticides at 5% fruit infestation provided the highest reduction of fruit infestation and produced the highest fruit yield of eggplant. Benefit / Cost analysis Benefit Cost Ratio (BCR) as worked out based on the expenses incurred and value of eggplant fruits obtained from different treatments of the present study for the suppressing of ESFB (Table 4). The (Ripcord = cypermethrin 10 1 ml/l of water sprayed after observing 5% level of fruit infestation and repetition of the same at 15 days interval), followed by Tk in T2, Tk in T1 and Tk in T4 treated plot. The highest benefit cost ratio was obtained in T3 (8.14) treated plot followed by 6.92 in case of T2. Treatment T1 and T4 showed the lowest benefit cost ratio i.e., 1.92 and 1.48 respectively. adjusted net return was highest (Tk ) in T3 Table 4. Economic analysis of the effect of ripcord (cypermethrin) for the control of eggplant shoot and fruit borer. Treat ments Total no. of application Cost of (Tk/ha) Management Fruit Yield Gross return Net return (Tk/ha) (t/ha) (Tk/ha) Adjusted net return (Tk) Benefit cost ratio (BCR) T T T T T Cost of Insecticide: l/ha spray material (water) needed for single spray in case of T1 and l/ha needed for single spray in case of other treatments. So, the management cost of the treatments are- T1 = ( *15 times*1.3 tk/ml ripcord) + (2 labour*250 tk/day*15 times) = tk/ha T2 = ( *4 times*1.3 tk/ml ripcord) + (2 labour*250 tk/day*4 times) = tk/ha T3 = ( *4 times*1.3 tk/ml ripcord) + (2 labour*250 tk/day*4 times) = tk/ha T4= ( *4 times*2ml/l*1.3 tk/ml ripcord) + (2 labour*250 tk/day*4 times) = tk/ha Ripcord 10 EC Tk. 130 /100 ml bottle Insecticide preparation and 2 labour/ha Labor Tk. 250/day. Market price of eggplant fruit was Tk. 20/kg. The BCR found in the study agree with those obtained by Naitam and Markad (2003), who stated that application of flubendiamide sprayed at 5% fruit damage gave the highest BCR (8.02). Latif et al. (2009) reported that flubendiamide 24WG 0.012% applied at 5% fruit infestation gave the highest BCR (7.45). Islam et al. (1999), reported that application of Fenom at 10% fruit infestation gave the highest BCR (6.2) compared to schedule spray. However, the BCR (8.14) of the present study at 5% level of fruit infestation may be acceptable though the management of crop pest varies with the market value of products, socioeconomic conditions, cost of pesticides etc. In this study we found that, Ripcord (cypermethrin) 10 1 ml/l of water sprayed after observing 5% level of fruit infestation and repetition of the same at 15 days interval (T3) performed best than the other treatments. As a result it might be a suggestions for the farmers not to use insecticide indescriminately but the use of minimum level of insecticide for the maximum level of benefit. 358 Rahman et al.

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