Crop loss assessment and ecofriendly management of Aphids, Aphis gossypii (Glover) on Isabgol, Plantago ovata (Forst)

Introduction

Medicinal plants form a vital component of traditional healthcare systems and contribute significantly to global trade. Among these, Isabgol (Plantago ovata Forsk.), commonly known as psyllium, is an economically important medicinal crop valued for its mucilaginous seed husk, widely used in pharmaceutical, nutraceutical and food industries. India is the largest producer and exporter of Isabgol, with major cultivation concentrated in Gujarat, Rajasthan, Maharashtra and Madhya Pradesh. Isabgol thrives in warm temperate climates and produces seeds rich in mucilage, which is utilized as a bulk-forming laxative and in the management of various gastrointestinal disorders. Psyllium husk also offers several health benefits, including hypoglycemic, hypo cholesterol emic, antioxidant and anti-ulcer properties. Isabgol productivity is constrained by several insect pests. Among these, the aphid Aphis gossypii (Glover) is a major sap-sucking pest causing leaf curling, stunted growth, poor spike formation and significant yield loss, particularly during flowering and seed-setting stages. Infestations are common in Maharashtra, yet systematic studies on its management remain limited. Evaluating eco-friendly biopesticides and sustainable management strategies is essential for safe and effective suppression of A. gossypii in Isabgol cultivation.

Methodology

The investigation entitled "crop loss assessment and eco-friendly management of aphids, Aphis gossypii Glover on Isabgol (Plantago ovata)" was conducted at AICRP on MAP and Betelvine, MPKV, Rahuri during Rabi 2024-25 with the Isabgol variety Gujarat Isabgol-1 was used. The experiment was laid out in a Randomized Block Design with 9 treatments and 3 replications. Plot size measured 4 m × 3 m. Sowing was done on 12 November 2024 and harvesting on 12-13 April 2025.

Yield Loss Assessment due to Aphis gossypii on Isabgol

A field experiment was conducted to quantify the impact of Aphis gossypii infestation on the seed yield of Isabgol (Plantago ovata Forsk.) under treated and untreated conditions. The study included replicated plots treated with Spinosad and untreated control plots. Yield increase over control and avoidable yield loss were calculated following Poul (1976), whereas the Net Incremental Cost-Benefit Ratio (NICBR) was estimated using treatment cost and yield data. Aphid populations were recorded weekly throughout the crop season. In each plot, ten plants were randomly selected and all visible aphids were counted manually during morning hours to minimize diurnal variation. Mean aphid population per plant was used to assess infestation dynamics and treatment efficacy. At maturity, each plot was harvested separately. The produce was dried, cleaned and weighed, and yields were expressed in kg/ha. The data from treated and untreated plots were statistically compared using a t-test to determine the significance of yield differences. For determine of increase in yield over control and avoidable loss, following formula given by Poul (1976) were used:

Insecticidal Treatments and Aphid Incidence Bioefficacy of insecticidal and biopesticidal sprays was evaluated through systematic observations taken before and after application. Treatments were applied as foliar sprays using a calibrated knapsack sprayer at 500 L/ha. Two sprays were given at 15-day intervals, with the first applied on 7 February 2025 when aphid populations reached the economic threshold. Pre-spray counts were taken one day before the first spray, followed by post-spray observations on the 3 rd , 7 th and 14 th day after each application. The 14 th day count after the first spray served as the pre-spray count for the second application. In each plot, five plants were randomly selected at each interval. All visible aphids on leaves, stems and inflorescences were counted manually. The mean population was used for statistical analysis. Data were analyzed using RBD.

Seed Yield of Isabgol

The crop was harvested when spikes and peduncles turned reddish-brown. The seed yield was recorded in kg/ha for further analysis.

Result and discussion

Avoidable Yield Loss Due to Aphis gossypii

A field experiment with treated and untreated plots across ten replications assessed the impact of A. gossypii infestation on Isabgol yield. Spinosad 45% SC effectively suppressed aphids, with treated plots recording a mean of 6.17 aphids/plant compared to 57.63 aphids/plant in untreated plots. Reduced aphid incidence in treated plots resulted in higher yields (mean 804.70 kg/ha), whereas untreated plots recorded substantially lower yields (mean 571.10 kg/ha). Yield loss in untreated plots ranged from 27.33% to 30.08%, with an average avoidable loss of 29.02%. The highest yield loss (30.08%) corresponded to replications with greater aphid pressure. Previous studies also highlight the substantial impact of aphid damage on crop productivity. Patel et al. (2004) [9] reported yield losses of up to 100% in unprotected mustard, emphasizing the need for timely pest management. The present findings are comparable with those of Kumar et al.

(2022) [5] , who observed 25.92-26.25% loss in mustard, and slightly higher than the 4.56-12.51% loss reported by Fakhouri et al. (2021) [3] in lentil. However, they remain lower than the severe losses noted by Faheem et al. (2022) [2] in Brassica juncea (70.77%) and Thorat et al. (2024) [12] in safflower (79.10%). The yield advantage recorded in treated plots is consistent with Singh (2024), who also reported significant yield improvement following aphid management practices.

Bioefficiency of plant products and biopesticides against aphids, Aphis gossypii on Isabgol, Plantago ovata

A field experiment evaluated nine treatments, including entomopathogenic fungi, botanicals, neem-based formulations, microbial metabolites and a chemical insecticide, against Aphis gossypii on Isabgol. Pre-treatment aphid populations were statistically uniform across treatments. Three days after spraying, spinosad 45% SC recorded the sharpest decline, indicating strong immediate action. By 7 DAS, spinosad and azadirachtin maintained low aphid numbers, while Metarhizium anisopliae and NSE showed weak performance. At 14 DAS, Lecanicillium lecanii produced the lowest aphid population, reflecting superior residual efficacy. Percent reduction at 14 DAS was highest in L. lecanii (73.33%), followed by azadirachtin (71.32%) and Beauveria bassiana (63.24%). Spinosad and neem oil showed moderate suppression, while abamectin, NSE and M. anisopliae were less effective. The study highlights L. lecanii, azadirachtin and B. bassiana as the most reliable treatments for sustainable aphid management in Isabgol. The second spray evaluation showed significant differences in aphid suppression across treatments. At 3 DAS, spinosad (T7) recorded the lowest aphid count, followed by azadirachtin (T4) and Lecanicillium lecanii (T1), indicating rapid initial action. By 7 DAS, azadirachtin showed the minimum population, whereas spinosad exhibited reduced residual activity. At 14 DAS, L. lecanii maintained the lowest aphid population, followed by azadirachtin and Beauveria bassiana. Percent reduction at 14 DAS was highest in L. lecanii (73.37%), azadirachtin (71.34%) and B. bassiana (63.19%). Spinosad and neem oil provided moderate control, while M. anisopliae and NSE remained less effective. The cumulative evaluation of two sprays revealed significant differences among treatments across all observation periods. At 3 DAS, spinosad recorded the lowest aphid population, followed by abamectin and azadirachtin, whereas the untreated control remained highest. By 7 DAS, azadirachtin, Lecanicillium lecanii and Beauveria bassiana showed the most pronounced reductions, while M. anisopliae and the control maintained high infestation. At 14 DAS, L. lecanii achieved the lowest aphid count, with azadirachtin and B. bassiana also maintaining strong suppression. Percent reduction was highest in L. lecanii (73.35%), azadirachtin (71.33%) and B. bassiana (63.22%). Spinosad and neem oil offered moderate control, whereas abamectin and NSE were less effective. M. anisopliae showed minimal reduction and remained close to the untreated control. Field results were strongly supported by earlier research demonstrating the effectiveness of plant products and entomopathogenic fungi against A. gossypii. Several studies, including Patel (2002) [8] , Anitha & Nandihalli (2008) [1] and Gupta and Pathak (2009) [4] , highlighted the economic and biological efficacy of NSKE and neem oil across crops. Similar findings by Suganthy and Sakthivel (2012) [10] and Vinodhini and Malaikozhundan (2011) [13] further confirmed neem-based products as reliable aphid suppressants. Recent findings (Landge 2023 [6] ; Tathode 2024) [11] reaffirmed L. lecanii and azadirachtin as eco-friendly and effective options.

Yield

Spinosad yielding the highest seed output (8.08 q/ha), followed by azadirachtin (7.47 q/ha) and L. lecanii (7.13 q/ha). M. anisopliae recorded the lowest yield among treated plots, marginally above the untreated control. The additional yield over the control indicated clear economic benefits of effective aphid management in Isabgol. Spinosad recorded the highest net gain (2.20 q/ha), followed by azadirachtin (1.59 q/ha) and abamectin (1.34 q/ha), while Metarhizium anisopliae showed minimal advantage (0.37 q/ha). The highest percent increase in yield over control was again observed with spinosad (37.41%), supported by azadirachtin (27.04%) and abamectin (22.78%). Treatments such as Lecanicillium lecanii and neem oil also enhanced yield by 21.25% and 18.02%, respectively, indicating suitability for eco-friendly production systems. In contrast, M. anisopliae showed the lowest improvement (6.29%).

Economic

Spinosad the highest seed yield (8.08 q/ha), followed by azadirachtin, abamectin and L. lecanii. Overall, bio-rational treatments provided substantial yield and economic gains over the untreated control.

Acknowledgement

AcknowledgementAuthors express sincere thanks to the Head, Department of Entomology, Mahatma Phule Krishi Vidyapeeth, Rahuri, Maharashtra, for providing necessary facilities and encouragement during investigation.

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