20199-- Saswati Premkumari

Indian Journal of Entomology 83(2021) Online published Ref. No. e20199 DoI No.: 10.5958/0974-8172.2020.00253.9

EFFICACY OF SOME INSECTICIDES AGAINST MAJOR PESTS OF LONG DURATION PIGEONPEA

Saswati Premkumari*, C P Srivastava, Sabuj Ganguly and Ram Keval

Department of Entomology and Agricultural Zoology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi 221005 *Email: [email protected] (corresponding author)

ABSTRACT

The efficacy and economics of some newer insecticides against three major insect pests of long duration pigeonpea viz. Melanagromyza obtusa, and were evaluated. The treatments included- Spinosad 45SC @ 73 g a.i./ ha, emamectin benzoate 5SG @ 250 g a.i./ ha, fipronil 80WG @ 50 g a.i./ ha, profenophos 50EC @ 500 g a.i./ ha, acetamiprid 20SP @ 20 g a.i./ ha and acephate 75SP @ 750 g a.i./ ha. The results showed that the grain damage due to pod fly and pod bug was lowest in acetamiprid 20SP (9.97 and 1.96%, respectively) followed by fipronil 80WG. Maximum grain yield was obtained with acetamiprid 20SP (1180.85 kg/ ha) followed by fipronil 80WG (1150.50 kg/ ha) and spinosad 45SC (1140.55 kg/ ha). The cost effectiveness of acetamiprid and fipronil was very high with a cost-benefit ratio (CBR) of 1:12.63 and 1: 8.17, respectively. Key words: Pigeonpea, Melanagromyza obtusa, Clavigralla gibbosa, Helicoverpa armigera, grain damage, grain yield, CB ratio, acetamiprid, fipronil, spinosad Pigeonpea [Cajanus cajan (L.) Millsp.] is a tropical 10 cm between plants. was taken for this trial. Treatments grain legume mainly cultivated in and commonly included: T1- spinosad 45SC@73 g a.i./ ha, T2-emamectin known as red gram or tur or arhar (Sreekanth et al., benzoate 5SG@ 250 g a.i./ ha, T3- fipronil 80WG @ 50

2014). Insect pests pose great threat to its production g a.i./ha, T4- profenophos 50EC @ 500 g a.i./ ha, T5- that result in poor yield. About 250 species of acetamiprid 20SP @20 g a.i./ ha, and T6 - acephate 75SP@ belonging to 8 orders and 61 families infest the 750 g a.i./ ha. The crop received two sprays, first at 50% crop (Patra et al., 2016). Those which attack at the of pod formation and second at 15 days after the first, as reproductive stages of the crop are the serious ones the pest population reached its economic threshold level. viz. pigeonpea pod borer, Helicoverpa armigera After harvesting, in two random plants/ plot 100 pods (Hubner), blue butterflies, Lampides boeticus L., were plucked and grain damage observed. All the pods plume , atomosa (Walsingham), tur were then threshed separately and grain yield/ plot was pod bug Clavigralla gibbosa (Spinola) and pod fly, recorded after discarding the damaged grains, and then Melanagromyza obtusa (Malloch), with losses up to converted into kg/ ha, before the cost- benefit ratios were 78%. Among these, M. obtusa, C. gibbosa, H. armigera calculated. Benefit cost ratio (BCR) was also assessed by are important as they cause maximum damage in long dividing the net monetary return by the total additional duration pigeonpea. On an average 2-2.4 mt of pulses cost due to treatments as worked out (insecticides cost are lost annually due to pest complex (Reddy, 2009). and labour charges) (Narasimhamurthy and Keval, 2013). Management of these relies mainly on insecticides, The data on economics were statistically analyzed (SE and large scale indiscriminatory use of these has led to and CD, p = 0.05). several problems. Hence, need based use of effective RESULTS AND DISCUSSION insecticides is necessary, and the present study on this. MATERIALS AND METHODS The results obtained on the efficacy and cost benefit ratio of insecticides against M. obtusa, C. gibbosa and The field experiment was conducted at the H. armigera on pigeonpea are presented in the Table Entomological Trial Field, Institute of Agricultural 1. These reveal that grain damage due to M. obtusa Sciences, Banaras Hindu University, Varanasi during was minimum (9.97%) with acetamiprid 20SP @ 20 g kharif 2017-18 on Bahar variety (8 months duration). a.i./ ha, and maximum with profenophos 50EC @500g Randomized Block Design was followed with six a.i./ ha (11.37%), against 13.81% in untreated control. treatments and an untreated control replicated twice in 4 x These results agree with those of Sambathkumar et al. 3 m plots maintaining spacing of 75 cm between rows and (2015) with chlorantraniliprole 18.5SC @ 30 g a.i./ ha; 2 Indian Journal of Entomology 83(2021) Online published Ref. No. e20199

Table 1. Efficacy and cost benefit analysis of insecticides on long duration pigeonpea (kharif, 2017-18) % grain damage Grain Increase in yield Value of Cost of Profit due Cost M. C. H. yield over untreated incremental treatment to treatment benefit Treatments obtusa gibbosa armigera (kg/ ha) control (%) yield (Rs) (Rs/ ha) (Rs) ratio Spinosad 10.36 2.58 2.24 1140.55 37.35 16,894.46 3138.18 13,686.28 1:4.36 45 SC (73g) (18.76) (9.22) (8.59) Emamectin 11.17 3.13 2.21 1110.00 33.66 15,229.48 3,900 11,329.48 1:2.90 benzoate (19.50) (10.17) (8.36) 5SG (250g) Fipronil 10.10 2.30 2.30 1150.50 38.47 17,436.73 1900 15,536.73 1:8.17 80WG (50g) (18.51) (8.71) (8.69) Profenophos 11.37 3.88 2.78 1040.89 25.30 11,462.99 1810 9652.99 1:5.33 50EC (500 ml) (19.69) (11.38) (9.50) Acetamiprid 9.97 1.96 3.40 1180.85 42.27 19,090.81 1400 17,690.81 1:12.63 20SP (20g) (18.51) (9.56) (10.60) Acephate 10.53 2.71 2.25 1070.50 28.91 11,986.73 1780 10,206.73 1:5.73 75SP (750g) (18.91) (9.41) (8.55) Untreated 13.81 5.00 3.94 830.56 0.00 - - - - control (21.79) (12.92) (11.43) S.E(m)± 0.63 0.54 0.48 21.90 2.67 - - - - C.D. at 5% 1.96 1.69 1.51 68.23 8.30 - - - - Cost of inputs: Spinosad- Rs.15,330/ l, emamectin benzoate- rs.6000/ kg, fipronil- rs. 500/ kg, profenophos- rs.455/ lit, acephate- Rs.440/ kg, No. of unskilled labour required/ spray-k, Wage of labour/ day- Rs. 450, No. of sprays-Two, market price of pigeonpea- Rs.54.5/ kg.

and Sharma et al. (2011) with emamectin benzoate+ REFERENCES

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