Efficacy of chemical insecticides against rice gall midge, Orseolia oryzae (Wood-Mason) at Bastar region

Introduction

Rice (Oryza sativa L.) is the world's single most important crop, belonging to the family Poaceae. It is one of the most important cereals and a staple diet for more than 2 billion people. With a yield of roughly 118.43 million tonnes and an average productivity of 2.75 tonnes ha -1 , rice was produced on approximately 43 million hectares in India. (Anonymous, 2020 a) [1] . About 82% of the people living in the state of Chhattisgarh, which is referred to as the "rice bowl of India," depend on agriculture for their livelihood. With a yield of 6.5 million tonnes and a productivity of 1.77 tonnes ha -1 , there were 3.6 million hectares of rice growing land in total. (Anonymous, 2020 b) [2] . Total production of rice during 2021-22 was recorded at 127.93 million tonnes. It was higher by 11.49 million tonnes than the last five years average production of 116.44 million tonnes (Anonymous, 2022) [3] . In previous decades, Ridley (1881) [19] initially reported an unknown insect pest on rice in the Monghyr area of Bihar, India; Wood-Mason later identified the pest as Cecidomyia oryzae (Cotes, 1889) [6] . The Asian rice gall midge Orseolia oryzae (Wood-Mason) (Diptera: Cecidomyiidae) is a serious pest of rice (Oryza sativa L.) in India, causing an average annual yield loss of about US $80 million (Bentur et al., 2003) [4] . According to estimations for yield loss, silver shoot damage caused by 1% gall midge caused a 3.5% loss (Muralidharan and Pasalu, 2005) [14] . Orseolia oryzae and Orseolia oryzivora's mature flies have wings that are 3.0-3.5 mm for males and 3.5-4 mm for females, making them roughly the size of mosquitoes. They are phototropic and nocturnal. The males' abdomens are darker in colour, while the females are bright red and stout. The female-to-male ratio in Orseolia oryzae field populations is typically 4:1, but it is 1:1 in Orseolia oryzivora. The adults have a lifespan of 2 to 5 days and feed on dewdrops. Soon after emergence, copulation often occurs and lasts for about five minutes. A few hours later, there is oviposition. Unmated females deposit infertile eggs, and the females only mate once. No parthenogenesis has been seen. A single female is capable of depositing anywhere between 100 and 200 eggs, either single or in clusters of three to four near the base of the plants, on the ligules or nearby, on the leaf blade, or on the leaf sheath. Regular tillers are damaged when they change into tubular galls that dry up without producing panicles.

The pest begins by infesting the seedbed plants and keeps doing so up until the booting stage. The larvae cannot live on a crop past the vegetative stage since they can only develop on developing primordia (Pathak and Khan, 1994) [16] . The rice gall midge produces monogenous progeny, where in all off springs of a single females are of one sex only (Sain and Kalode, 1988) [20] . The occurrence of a femalebiased sex ratio in a population, with male-producing females and female-producing females in the ratio of 1:1.32, is an interesting characteristic of the gall midge life cycle. (Panda and Mohanty, 1970) [15] . The young larvae of the gall midge, which take around two to three weeks to develop, do more damage. An active first instar larva at the meristem promotes the creation of a gall and inhibits the growth of the growth cone, causing the developing tips to be distorted into the shape of a gall and transform into "onion tips" or "silver shoots." A molecular "signal," or "cecidogen," is produced by the salivary glands of feeding larvae (Chiu, 1980) [5] . Significant yield losses result from the damaged tillers' failure to produce panicles. When rice is damaged, the quantity of unproductive tillers rises while the quantity of productive spikes falls (Tan et al., 1996) [25] . Gall midge incidence was reported to be higher in late-sown crops and negatively correlated with yield (Kulkarni et al., 1989) [9] . Early sowing and transplanting to avoid gall midge attack has been practised successfully (Hegdekatti, 1927) [8] . The gall midge attacks rice from the nursery to the end of the tillering stage. The larvae of the gall midge fly cause heavy damage to the rice crop. The gall midge fly's larvae severely harm the rice crop. Early infection causes the tillers to produce gall, which prevents them from producing panicles. During the dry season, the gall midge is dormant as a prepupa in weeds or wild rice. It starts active at the beginning of the monsoon season and completes one or two generations in grasses before switching to the rice crop (Reddy, 1967) [18] . The seasonal occurrence of gall midges began in late August, peaked in October, and then started to drop in December (Sain and Kalode, 1992) [21] . The Asian Rice Gall Midge (Orseolia oryzae W. Both single and group egg laying occurred parallel to the midrib. Until they reached an apical or lateral bud's growth point, newly born maggots moved between leaf sheaths. The newly emerged maggots had a pointed anterior end and were grey in colour. The plant produces distinctive galls, which turn ordinary tillers into tubular galls that dry up without yielding panicles. The gall is produced by the maggots as they eat within the developing bud and harm the growth points. An onion shoots or silver shoot is one way that damage manifests itself. The pest begins by infesting the seedlings and might carry on doing so until they are ready to boot. From September through October, they are active. Additionally, several areas of Kerala, Orissa, Andhra Pradesh, Madhya Pradesh, Jharkhand, and Bihar are negatively affected. In north eastern UP, the loss caused by this pest is very low but in Jharkhand, Prasad, (2011) [17] estimated 20-70% loss due to infestation of rice gall midge.

Materials and Methods

The experiment was conducted at Research cum Instructional farm of Shaheed Gundadhoor College of Agriculture and Research Station, Jagdalpur, Baster (C.G.) 494001 during Kharif 2022 with Randomized Block Design (RBD). Rice variety "Swarna" evaluated against gall midge pests of rice with chemical insecticides. Nursery treatment was done with chemicals, i.e., carbofuran 3% GR, fipronil 0.3 GR and chlorantraniliprole 0.4 GR, one week before transplanting. The experimental field was divided into 3 replications, with 10 plots in each replication. The plot size was 20 m 2 and 20 x 15 cm spacing (R x P). The data observations were taken from 10 hills, which were selected randomly from each plot. The observation of gall midges infesting rice were recorded at 35, 50 and 65 DAT. The observation was recorded by counting damage done by rice gall midges, i.e., silver shoots (SS) on the basis of total numbers of tillers and gall midge damaged tillers (silver shoots) at the vegetative stage. According to Singh and Singh, 2017, the per cent damage was calculated by using the formula:

Number of silver shoots Total number of tillers × 100

Results and Discussion

Different insecticides were evaluated against gall midge of rice at SGCARS Farm, Kumhrawand, Jagdalpur, Bastar. The insecticides were applied in the nursery treatment and main field on rice crop. The insecticide molecules, Carbofuran 3% GR (Check) @ 3.3 g/m 2 , Fipronil 0.3 GR @ 2.5 g/m 2 , Chlorantraniliprole 0.4 GR @ 1.0 g/m 2 , Cartap hydrochloride 4% GR @ 1.9 g/m 2 and untreated control were evaluated for their efficacy against rice gall midge, Orseolia oryzae W. Perusal of data presented (Table 2) on efficacy of chemical insecticides against rice gall midge in field condition, observed that the insecticidal treatments were significantly superior to the untreated control. First observation was taken at 35 DAT (days after transplanting) in which T 8 -combine of nursery treatment and main field treatment of fipronil 0.3 GR @ 2.5 g/m 2 + chlorantraniliprole 0.4 GR @ 1.0 g/m 2 (T 2 + T 6 ) depicted minimum incidence of silver shoots (4.94 SS%) and the use of insecticides statistically at par with T 9combine of nursery treatment and main field treatment of fipronil 0.3 GR @ 2.5 g/m 2 + cartap hydrochloride 4% GR @ 1.9 g/m 2 (T 2 + T 7 ) with 5.87 SS%, followed by T 4carbofuran 3% GR (Check 2) @ 3.3 g/m 2 with 8.02 SS%, T 6 -chlorantraniliprole 0.4 GR @ 1.0 g/m 2 (9.73 SS%), T 7cartap hydrochloride 4% GR @ 1.9 g/m 2 (11.55 SS%), T 5fipronil 0.3 GR @ 2.5 g/m 2 (12.31 SS%), T 1-carbofuran 3% GR (Check 1) @ 3.3 g/m 2 (12.34 SS%), T 3chlorantraniliprole 0.4 GR @ 1.0 g/m 2 (12.57 SS%) and T 2fipronil 0.3 GR @ 2.5 g/m 2 (13.22 SS%). The highest incidence of silver shoot (23.76 SS%) was received in case of untreated plot. At 50 DAT (days after transplanting) all the insecticidal treatments were found to be significantly superior to the untreated control. Higher reduction per cent of silver shoots incidence were recorded from T 8 -combine of nursery treatment and main field treatment of fipronil 0.3 GR @ 2.5 g/m 2 + chlorantraniliprole 0.4 GR @ 1.0 g/m 2 (T 2 + T 6 ) depicted minimum incidence of silver shoots (6.09 SS%) and the use of insecticides statistically at par with T 9combine of nursery treatment and main field treatment of fipronil 0.3 GR @ 2.5 g/m 2 + cartap hydrochloride 4% GR @ 1.9 g/m 2 (T 2 + T 7 ) with 6.71 SS%, followed by T 4carbofuran 3% GR (Check 2) @ 3.3 g/m 2 (10.24 SS%), T 6chlorantraniliprole 0.4 GR @ 1.0 g/m 2 (11.16 SS%), T 5fipronil 0.3 GR @ 2.5 g/m 2 (13.24 SS%), T 7 -cartap hydrochloride 4% GR @ 1.9 g/m 2 (14.10 SS%), T 1carbofuran 3% GR (Check 1) @ 3.3 g/m 2 (15.89 SS%), T 3chlorantraniliprole 0.4 GR @ 1.0 g/m 2 (17.04 SS%) and T 2fipronil 0.3 GR @ 2.5 g/m 2 (18.09 SS%). The highest incidence of silver shoot (37.23 SS%) was received from T 10 -untreated plot. At 65 DAT (days after transplanting), the observations were recorded, the lowest incidence of silver shoots (5.28 SS%) showed in T 8 -combine of nursery treatment and main field treatment of fipronil 0.3 GR @ 2.5 g/m 2 + chlorantraniliprole 0.4 GR @ 1.0 g/m 2 (T 2 + T 6 ) which was at par with T 9-combine of nursery treatment and main field treatment of fipronil 0.3 GR @ 2.5 g/m 2 + cartap hydrocholoride 4% GR @ 1.9 g/m 2 (T 2 + T 7 ) with 6.75 SS%, followed by T 7 -cartap hydrochloride 4% GR @ 1.9 g/m 2 (11.67 SS%), T 4-carbofuran 3% GR (Check 2) @ 3.3 g/m 2 with 13.14 SS%, T 6 -chlorantraniliprole 0.4 GR @ 1.0 g/m 2 (13.52 SS%), T 5 -fipronil 0.3 GR @ 2.5 g/m 2 (15.96 SS%), T 1-carbofuran 3% GR (Check 1) @ 3.3 g/m 2 (21.15 SS%), T 3 -chlorantraniliprole 0.4 GR @ 1.0 g/m 2 (21.54 SS%) and T 2 -fipronil 0.3 GR @ 2.5 g/m 2 (22.03 SS%). The maximum incidence of silver shoot (33.02 SS%) was received from T 10 -untreated control.

All of the treatments were found to be significantly superior than the untreated control and it decreased the proportion of silver shoots, according to data (overall mean) collected (Table 2), regarding the effectiveness of insecticides against rice gall midge. Among the treatments, the best result was observed in T 8 -combine of nursery treatment and main field treatment in which fipronil 0.3 GR @ 2.5 g/m 2 + chlorantraniliprole 0.4 GR @ 1.0 g/m 2 (T 2 + T 6 ) were applied and recorded 5.44 SS% which was 82.65% reduction over control (ROC) and at par with T 9-combine of nursery treatment and main field treatment of fipronil 0.3 GR @ 2.5 g/m 2 + cartap hydrocholoride 4% GR @ 1.9 g/m 2 (T 2 + T 7 ) with 6.44 SS% which was 79.44% ROC, followed by T 4-carbofuran 3% GR (Check 2) @ 3.3 g/m 2 with 10.46 SS% and 66.61% ROC, T 6 -chlorantraniliprole 0.4 GR @ 1.0 g/m 2 (11.47 SS%) with 63.40% ROC, T 7 -cartap hydrochloride 4% GR @ 1.9 g/m 2 (12.44 SS%) with 60.31% ROC, T 5 -fipronil 0.3 GR @ 2.5 g/m 2 (13.84 SS%) with 55.85% ROC, T 1-carbofuran 3% GR (Check 1) @ 3.3 g/m 2 (16.46 SS%) with 47.48% ROC, T 3 -chlorantraniliprole 0.4 GR @ 1.0 g/m 2 (17.05 SS%) with 45.59% ROC and T 2fipronil 0.3 GR @ 2.5 g/m 2 (17.78 SS%) with 43.26% ROC.

The highest percentage of silver shoot (31.34 SS%) was recorded in case of T 10 -untreated plot. Earlier, Dakouo and Nacro (1987) [7] recorded that one application of carbofuran were effective based on counts of silver shoots at 45, 60 and 60 days after transplantation. In treated plots compared to untreated plots, yields were 1-2 t ha -1 greater. Singh et al. (2000) [23] evaluated the efficacy of several insecticides and observed that the percentage of silver (damaged) shoots at 60 DAT was 6.77% and 7.33% in the chlorpyrifos and carbofuran treatments in experiment 1 and all treatments were better than the monocrotophos treatment and untreated control. Seni and Naik (2017) [22] recorded the fipronil 5 SC @ 75 g a.i. ha -1 were best treatment which recorded 3.03 and 2.14% silver shoot in two observations. Similarly, Misra and Sahithi (2006) [13] showed the cartap hydrochloride-treated plots had the lowest incidence of silver shoots at 15 days after spraying, with a maximum reduction of 74.1-78.7%, followed by phosphamidon (2.1-3.7%), with a 61.0-80.0% reduction over control. Mardi et al. (2009) [12] observed that the carbofuran 3G was most effective against gall midge (SS%) and greater yield obtained (3032.5 kg ha -1 ) followed by chloropyriphos 40EC (2910.0 kg ha -1 ) and phorate 10G (2832.5 kg ha -1 ). Kumar et al. (2011) [10] recorded that the lowest gall midge infestation (4.98% silver shoot), higher grain (60.02 q ha -1 ) with 79.73% SS reduction over control when isazophos 3G @ 0.75 kg a.i. ha -1 applied in the nursery. This is followed by fipronil 0.3G @ 0.075 kg a.i. ha -1 (9.07% SS) which recorded 55.77 q ha -1 with 63.08% SS reduction over control and carbofuran 3G @ 1.0 kg a.i. ha -1 (7.96% SS) which recorded grain yields of 55.33 q ha -1 with 67.60% SS reduction over control.

Yield analysis and assessment of avoidable yield losses

The yields were obtained from different plots and all treatments had significantly superior than the untreated control. The data presented on Table 3 revealed that T 8fipronil 0.3 GR + chlorantraniliprole 0.4 GR (T 2 + T 6 ) was most effective with 54.50 q ha -1 yield when insecticide applied in the two times (Nursery + main field). The treatment showed 11.90 q ha -1 actual increase in yield over untreated control which accounted for 27.93 per cent increase in yield due to treatment with 21.83 per cent avoidable losses. This treatment was superior to T 9 -fipronil 0.3 GR + cartap hydrocholoride 4% GR (T 2 + T 7 ) with 52.63 q ha -1 yield which was 10.03 q ha -1 actual increase in yield over untreated control with 19.06% avoidable losses (%) in yield, followed by T 4 -carbofuran 3% GR (50.40 q ha -1 yield) with 15. 48% avoidable losses and T 6-chlorantraniliprole 0.4 GR (49.70 q ha -1 yield) with 14. 29% avoidable losses T 7cartap hydrochloride 4% GR, (48.35 q ha -1 yield) with 11.89% avoidable losses, T 5-fipronil 0.3 GR (48.13 q ha -1 yield) with 11.50% avoidable losses, T 1-carbofuran 3% GR (Check 1) (44.60 q ha -1 yield) with 4.48% avoidable losses and T 3-chlorantraniliprole 0.4 GR (44.00 q ha -1 yield) with 3.18% avoidable losses respectively, with 10.03, 7.80, 7.10, 5.75, 5.53, 2.00 and 1.40 q ha -1 actual increase in yield over control. The lowest yield (43.78 q ha -1 ) was found in T 2 -(Fipronil 0.3 GR) with 1.18 q ha -1 actual increase in yield over untreated control and 2.70 per cent avoidable losses but it was superior to T 10 (untreated check) with 42.60 q ha -1 yield.

The current findings partially supported with the work of Kumar et al. (2020) [11] recorded the 39.5 q ha -1 yield which was obtained from chlorantraniliprole 18.5% SC at 15 ml ha -1 .

From the data presented (Table 3) revealed that calculation of economic in different treatments was made by considering the net benefit Rs ha -1 of individual components and the insecticide cost benefit ratio. The rice MSP rate was 2040 Rs q -1 for 2022 at Chhattisgarh. During the experiment different insecticides were applied on rice at two times i.e., nursery and main field treatment. Based on the economics of the management of gall midge of rice on different treatments, the best treatment was T 8-fipronil 0.3 GR + chlorantraniliprole 0.4 GR (T 2 + T 6 ) @ 2.5 + 10 kg ha -1 with net benefit of 21656 Rs ha -1 and the next best treatment was T 9 -fipronil 0.3 GR + cartap hydrocholoride 4% GR @ 2.5 + 19 kg ha -1 with net benefit of 17571 Rs ha -1 , followed by T 6chlorantraniliprole 0.4 GR @ 10 kg ha -1 with net benefit of 12414 Rs ha -1 , T 4 -carbofuran 3% GR @ 33 kg ha -1 with net benefit of 12330 Rs ha -1 , T 7-cartap hydrocholoride 4% GR @ 19 kg ha -1 with net benefit of 9383 Rs ha -1 , T 5 -fipronil 0.3 GR @ 25 kg ha -1 with net benefit of 7588 Rs ha -1 , T 1carbofuran 3% GR (Check 1) @ 3.3 kg ha -1 with net benefit of 3542 Rs ha -1 , T 3-chlorantraniliprole 0.4 GR @ 1.0 kg ha -1 with net benefit of 2469 Rs ha -1 and the lowest net benefit was recorded in T 2 -fipronil 0.3 GR @ 2.5 kg ha -1 with net benefit of 1864 Rs ha -1 .

Insecticides cost benefit ratio (ICBR)

Cost benefit ratio of different insecticides when applied in the nursery and main field treatment viz; Carbofuran 3% GR, Fipronil 0.3 GR, Chlorantraniliprole 0.4 GR and Cartap hydrochloride 4% GR have been worked out in the context of suitability of individual insecticidal treatment which are presented in Table 3.

The maximum cost benefit ratio was found in the nursery treatment getting from T 1 -carbofuran 3% GR (Check 1) with 1:6.58 ICBR, followed by T 3 -chlorantraniliprole 0.4 GR with 1:6.38 ICBR and T 2 -fipronil 0.3 GR with 1:3.39 ICBR. Carbofuran gave higher cost benefit ratio in the nursery because it was used in lower quantity (1/10 ha -1 ) compared to main field treatment. In the main field treatment, the maximum cost benefit ratio (1:6.00) was found in T 6chlorantraniliprole 0. [12] recorded that the carbofuran which gave higher grain yield (3032.50 kg ha -1 ) than other treatment but in terms of cost benefit ratio remained lowest (1.52) due to higher price of insecticides. Similarly, Seni and Naik (2017) [22] found that the cost benefit ratio was recorded in cartap hydrochloride 50 WP @ 375 g a.i. ha -1 (1:5.55) and fipronil 5 SC @ 75 g a.i. ha -1 (1:3.40).

Conclusion

The present study revealed that T 8-fipronil 0.3 GR + chlorantraniliprole 0.4 GR (T 2 + T 6 ) was most effective against gall midges when insecticide applied two times (Nursery + main field). This treatment was superior to T 9fipronil 0.3 GR + cartap hydrocholoride 4% GR followed by T 4 , T 6 , T 7 , T 5 , T 1 , T 3 and T 2 respectively. So, it was proved that the all treatments had significantly superior than untreated control.

Acknowledgement

AcknowledgementOur sincere gratitude is extended to the IIRR in Hyderabad and the IGKV in Raipur, Chhattisgarh, India. For all of their help, inspiration, great advice, suggestions and recommendations, as well as their consistent enthusiasm throughout the research. I would like to express my sincere gratitude to my research adviser, Dr. N.C. Mandawi, for his continuous encouragement and to Shaheed Gundadhoor College of Agriculture and Research Station in Jagdalpur, Bastar (C.G.), which supplied the resources required to conduct this investigation.

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