3.1 Insecticides performance:
First Application of Insecticides (First Year: Rabi 2021)
Table 1 presents data showing leaf miner infestation at DBT (Pree-count) ranging from 42.67% to 46.67%, with no statistically significant differences observed among treatments. In untreated plots, leaf infestation ranged from 45.67% to 49.16%. At 1 DAT, chlorantraniliprole at 30 g a.i. ha-1 achieved the lowest leaf infestation rate of 31.45%, statistically comparable to cyantraniliprole at 90 g a.i. ha-1, which recorded 31.81% infestation. Thiamethoxam at 25 g a.i. ha-1 followed with a rate of 34.03%, similar to chlorantraniliprole + thiamethoxam (soil drench) at 150 g a.i. ha-1, dimethoate at 300 g a.i. ha-1, quinalphos at 250 g a.i. ha-1, and NSE 5%, ranging from 35.50% to 39.98%. The untreated plots showed the highest infestation rate at 45.67%.
A comparable trend was observed at 3 DAT, and by 7 DAT, chlorantraniliprole at 30 g a.i. ha-1 maintained superiority with the lowest infestation rate of 16.33%. Cyantraniliprole at 90 g a.i. ha-1, thiamethoxam at 25 g a.i. ha-1, and chlorantraniliprole + thiamethoxam (soil drench) at 150 g a.i. ha-1 followed closely with rates of 17.69%, 18.22%, and 19.79%, respectively. Quinalphos at 250 g a.i. ha-1, dimethoate at 300 g a.i. ha-1, and NSE 5% were next in efficacy. Untreated control plots recorded the highest infestation rate at 49.16%.
Second Application of Insecticides (First Year: Rabi 2021)
In Table 1, leaf miner infestation at DBT (Pree-count) ranged from 21.17% to 51.45%, with no statistically significant differences among treatments, indicating uniform infestation levels. Untreated control plots exhibited infestation rates from 53.11% to 57.03%. At 1 DAT, chlorantraniliprole at 30 g a.i. ha-1 achieved the lowest leaf infestation rate at 16.19%, comparable to cyantraniliprole at 90 g a.i. ha-1 (17.05%), thiamethoxam at 25 g a.i. ha-1 (17.90%), and chlorantraniliprole + thiamethoxam (soil drench) at 150 g a.i. ha-1 (18.63%). Quinalphos at 250 g a.i. ha-1 followed with a 24.63% infestation rate, similar to dimethoate at 300 g a.i. ha-1 and NSE 5% at 25.41% and 30.67%, respectively. Untreated plots had the highest infestation rate at 53.11%.
A similar pattern was observed at 3 DAT, and by 7 DAT, chlorantraniliprole at 30 g a.i. ha-1 maintained effectiveness with the lowest infestation rate of 6.76%. Cyantraniliprole at 90 g a.i. ha-1 (7.72%), chlorantraniliprole + thiamethoxam (soil drench) at 150 g a.i. ha-1 (8.23%), and thiamethoxam at 25 g a.i. ha-1 (9.75%) followed closely. Quinalphos at 250 g a.i. ha-1, dimethoate at 300 g a.i. ha-1, and NSE 5% were subsequent in effectiveness. Untreated control plots recorded the highest infestation rate at 57.03%.
Overall mean (Rabi-2020)
The overall mean of leaf miner infestation in Table 1 of the Rabi-2020 study indicated that all treatments were significantly superior to the untreated plots. Chlorantraniliprole at 30 g a.i. ha-1 consistently proved to be the most promising, recording the lowest infestation rate of 17.97%. Following this, cyantraniliprole at 90 g a.i. ha-1, thiamethoxam at 25 g a.i. ha-1, and the combination of chlorantraniliprole and thiamethoxam (soil drench) at 150 g a.i. ha-1 recorded infestation rates of 19.28%, 20.43%, and 21.11%, respectively. Dimethoate at 300 g a.i. ha-1 was the next most effective treatment, with an infestation rate of 26.74%, which was comparable to quinalphos at 250 g a.i. ha-1 and NSE 5%, recording rates of 27.35% and 30.55%, respectively.
First Application of Insecticides (Second Year: Rabi 2021)
Table 1 shows leaf miner infestation at DBT (Pre-count) ranging from 41.39% to 48.67%, with no statistically significant differences among treatments. Conversely, untreated control plots exhibited infestation rates ranging from 50.73% to 53.10%. At 1 DAT, chlorantraniliprole at 30 g a.i. ha-1 achieved the lowest leaf infestation rate of 34.67%, statistically similar to cyantraniliprole at 90 g a.i. ha-1, thiamethoxam at 25 g a.i. ha-1, and chlorantraniliprole + thiamethoxam (soil drench) at 150 g a.i. ha-1, which recorded infestation rates of 35.33%, 36.20%, and 36.33%, respectively. Quinalphos at 250 g a.i. ha-1 followed closely with a 43.28% infestation rate, comparable to dimethoate at 300 g a.i. ha-1 and NSE 5%, at 42.45% and 43.33%, respectively. The untreated plots showed the highest infestation rate at 50.73%.
A similar trend in effectiveness was observed at 3 DAT. By 7 DAT, chlorantraniliprole at 30 g a.i. ha-1 maintained its lead with the lowest infestation rate of 21.53%. This was statistically similar to cyantraniliprole at 90 g a.i. ha-1, chlorantraniliprole + thiamethoxam (soil drench) at 150 g a.i. ha-1, and thiamethoxam at 25 g a.i. ha-1, which showed infestation rates of 22.97%, 23.76%, and 23.99%, respectively. Quinalphos at 250 g a.i. ha-1, dimethoate at 300 g a.i. ha-1, and NSE 5% followed in efficacy, with untreated plots recording the highest infestation rate at 53.10%.
Second Application of Insecticides (Second Year: Rabi 2021)
Table 1 reveals leaf miner infestation at DBT (Pre-count) ranging from 25.13% to 55.25%, with no statistically significant differences among treatments, indicating a uniform level of infestation. In untreated control plots, infestation ranged from 54.89% to 57.30%. At 1 DAT, chlorantraniliprole at 30 g a.i. ha-1 recorded the lowest leaf infestation rate at 19.20%. This was statistically comparable to cyantraniliprole at 90 g a.i. ha-1, thiamethoxam at 25 g a.i. ha-1, and chlorantraniliprole + thiamethoxam (soil drench) at 150 g a.i. ha-1, which showed infestation rates of 20.66%, 21.67%, and 22.01%, respectively, at the 0.05% significance level. Dimethoate at 300 g a.i. ha-1 followed with a 31.19% infestation rate, similar to quinalphos at 250 g a.i. ha-1 (32.31%) and NSE 5% (33.33%). The highest infestation rate of 54.89% was observed in the untreated plots. A comparable pattern of effectiveness was seen at 3 DAT. By 7 DAT, chlorantraniliprole at 30 g a.i. ha-1 remained the most effective, achieving the lowest infestation rate at 7.73%. This was statistically similar to cyantraniliprole at 90 g a.i. ha-1, thiamethoxam at 25 g a.i. ha-1, and chlorantraniliprole + thiamethoxam (soil drench) at 150 g a.i. ha-1, which recorded infestation rates of 8.94%, 9.21%, and 10.84%, respectively. Dimethoate at 300 g a.i. ha-1 was the next most effective, with an infestation rate of 18.23%, statistically similar to quinalphos at 250 g a.i. ha-1, followed by NSE 5%. The untreated plots had the highest infestation rate at 57.30%.
Overall mean (Rabi-2021)
The Rabi-2021 (Table 1) study evaluated various treatments for their effectiveness in reducing leaf miner infestation. Chlorantraniliprole at 30 g a.i. ha-1 demonstrated the highest efficacy, resulting in a leaf infestation rate of 20.35%. Following this, cyantraniliprole at 90 g a.i. ha-1 and thiamethoxam at 25 g a.i. ha-1 showed significant effectiveness, with infestation rates of 21.50% and 22.36%, respectively. The combination of chlorantraniliprole and thiamethoxam (soil drench) at 150 g a.i. ha-1 produced an infestation rate of 22.89%. Dimethoate at 300 g a.i. ha-1 resulted in a moderate infestation rate of 31.72%, which was comparable to quinalphos at 250 g a.i. ha-1, recording 31.88%. NSE 5% was the least effective among the treatments, with an infestation rate of 33.88%. All treatments significantly reduced leaf miner infestation compared to untreated plots, with chlorantraniliprole at 30 g a.i. ha-1 being the most effective.
Pooled of Fiest and Second year:
The pooled (Rabi-2020 & Rabi-2021) mean of leaf miner infestation appended in Table 1 indicated that all treatments were significantly superior @ 0.05% level of significance over the untreated plots ((P-value 0.05%). Chlorantraniliprole @ 30 g a.i. ha-1 consistently proved to be the most promising by recording lowest (19.16) per cent leaf infestation. However, other treatments follow the Chlorantraniliprole @ 30 g a.i. ha-1 in the sequence, cyantraniliprole. @ 90 g a.i. ha-1, thiamethoxam @ 25 g a.i. ha-1 and chlorantraniliprole + thiamethoxam (soil drench) @ 150 g a.i. ha-1 which recorded 20.39, 21.39 and 22.00 per cent leaf infestation, respectively. Dimethoate @ 300 g a.i. ha-1 was the next effective treatment by recording 28.78 per cent leaf infestation but it was at par with quinalphos @ 250 g a.i. ha-1 and NSE 5% (Fig. 1).
3.2 Effect on yield:
The yield data of two years are presented in Table 2. The results showed that, plots treated with chlorantraniliprole @ 30 g a.i. ha-1 registered highest yield (7.46 t ha-1). It was, however at par with cyantraniliprole @ 90 g a.i. ha-1, thiamethoxam @ 25 g a.i. ha-1 and chlorantraniliprole + thiamethoxam (soil drench) @ 150 g a.i. ha-1 which recorded 7.31, 7.24 and 6.61 t ha-1 yield, respectively. Quinalphos @ 250 g a.i. ha-1 was the next effective treatment (6.15 t ha-1) followed by dimethoate @ 300 g a.i. ha-1 and NSE 5% which recorded 6.05 and 5.75 t ha-1 yield, respectively. The data appended in Table 2 also indicate that a higher per cent increase in yield over control at 0.05 % level of significance was observed in plots treated with chlorantraniliprole 30 g a.i. ha-1 (58.38 %). It was followed by cyantraniliprole @ 90 g a.i. ha-1, thiamethoxam @ 25 g a.i. ha-1 and chlorantraniliprole + thiamethoxam (soil drench) @ 150 g a.i. ha-1 by recording 55.20, 53.71 and 40.33 per cent increase yield over control, respectively. Quinalphos @ 250 g a.i. ha-1 (30.57 %), dimethoate @ 300 g a.i. ha-1 (28.45 %) and NSE 5 % (22.08 %) were the next to follow in the descending order (Fig. 2).
3.3 Cost economic of treatment:
The cost effectiveness of the different insecticides used during the study was evaluated and presented in Table 3. The benefits reaped from every rupee investment in plant protection was highest (1: 28) in thiamethoxam @ 25 g a.i. ha-1. It was followed by NSE 5% (1: 11). Quinalphos @ 250 g a.i. ha-1, dimethoate @ 300 g a.i. ha-1 and chlorantraniliprole @ 30 g a.i. ha-1 were the next in order by recording ICBR of 1: 10, 1: 9.9 and 1: 9.1, respectively. The lowest ICBR was recorded in the treatment cyantraniliprole @ 90 g a.i. ha-1 (1: 2.1) and chlorantraniliprole + thiamethoxam (Soil drench) @ 150 g a.i. ha-1 (1: 2.5) because of their higher market price.
The overall performance of selected chemical and plant extract against leaf miner on fenugreek in descending order was: Chlorantraniliprole > Cyantraniliprole > Thiamethoxam > Chlorantraniliprole + Thiamethoxam (Soil Drench) > Quinalphos > dimethoate > NSE 5 %.
Chlorantraniliprole and Cyantraniliprole belong to the anthranilic Diamide group and have similar mode of action.