Population dynamics of M. obtuse
Damage caused by
M.
obtusa were recorded from the pod initiation stage to the maturity of crop. The first appearance of pod fly
M.
obtusa was noticed on 3rd Standard Meteorological Week (SMW) of 2021. The maximum pod damage (90%) was observed in 8th SMW followed by (85%) in 9th SMW and minimum pod damage (37.5%) was recorded in 12th SMW. Pod damage were increased continuously from 3rd, 4th and 5th SMW
i.
e. (53%), (68%) and (71.66%), respectively. thereafter damage suddenly went down in 6th SMW (58.33%) and 7th SMW (55%). Pod damage was demeaned from 10th SMW (61.45%) to 12th SMW (37.5%) (Table 1). Simple correlation between pod damage and weather parameters were non–significant.
Similarly, highest grain damage (83.33%) was observed in 8th SMW of the year 2022. followed by (73%) in 9th SMW and minimum grain damage (21.55%) was recorded in 12th SMW. Grain damage were increased continuously from 3rd, 4th and 5th SMW
i.
e., 38%, 45% and 49.3%, respectively. Thereafter, damage suddenly declined in 6th SMW (43.33%) and 7th SMW (30%). However, in 8th (83.33%) and 9th (73%) SMW grain damage was massively increased when temperature was increased. Grain damage declined from 10th SMW (39.9%) to 12th SMW (21.55 %). Simple correlation between grain damage and weather parameters was found to be non-significant (Table 2).
The maximum pod damage (74%) was observed in 8th SMW of 2022 followed by (69.3%) in 9th SMW and minimum pod damage (38.0%) was recorded in 12th SMW. Pod damage were increased continuously from 3rd, 4th and 5th SMW
i.
e., 48%, 62% and 64.3%, respectively, thereafter damage suddenly dropped down in 6th SMW (56.7%) and 7th SMW (49.3%). Pod damage was demeaned from 10th SMW (56.8%) to 12th SMW (38.0%) (Table 1). Simple correlation between pod damage and weather parameters were non–significant (Table 2).
Similarly, highest grain damage (62.0%) was observed in 8th SMW of the year 2022 followed by (58.0%) 9th SMW and minimum grain damage (24.0%) was recorded in 12th SMW. Grain damage were increased continuously from 3rd, 4th and 5th SMW
i.
e., 33%, 39.0% and 45.0%, respectively. Thereafter, damage suddenly declined in 6th SMW (42.0%) and 7th SMW (35.0%). Grain damage declined from 10th SMW (45.6%) to 12th SMW (24.0%) (Table 1). Simple correlation between grain damage and weather parameters was found to be non-significant (Table 2). According to
(Shanker et al., 2021) simple correlation between pod fly (larvae and pupae) with weather parameter revealed that maggot population showed non-significant positive correlation with minimum and maximum temperature (0.279 and 0.111).
(Subharani et al., 2007) also reported that correlation studies showed that the infestation of the pest on the crop was non- significant with any of the environmental factors, except for relative humidity.
Bio-efficacy of insecticides
During
kharif 2020, the pod damage was recorded 23.52% to 54.71%. The minimum pod damage (23.52%) was recorded in in Emamectin benzoate + Dimethoate followed by Chlorantraniliprole with 26.4% pod damage, Dimethoate with 26.95% pod damage and maximum pod damage 54.71% was recorded from untreated plots (Table 3). The Emamectin benzoate + Dimethoate was statistically at par with Chlorantraniliprole and Dimethoate, whereas, statistically superior over rest of the treatments. Azadirachtin, Emamectin + Acephate and Cyantraniliprole were at par with each other, whereas, these treatments were superior over spinosad. All the chemicals were significantly superior over control in reducing the pod damage (Table 3).
The grain damage was recorded 13% to 34.60%. The minimum grain damage was 13% recorded in treatment Emamectin benzoate + Dimethoate followed by treatment Chlorantraniliprole with 17.8% grain damage, Dimethoate with 18.5% grain damage and maximum grain damage 34.60% was recorded from untreated plots. Whereas, the Chlorantraniliprole, Dimethoate and Emamectin benzoate + Acephate were at par with each other. Azadirachtin and Cyantraniliprole were at par with each other. All the treatments were significantly superior over control in reducing the grain damage (Table 3).
Maximum per cent control in pod damage was recorded in treatment Emamectin benzoate + Dimethoat (31.19%) followed by Chlorantraniliprole (28.31%), Dimethoate (27.76%), Emamectin benzoate + Acephate (25.78%), Azadirachtin (22.85%), Cyantraniliprole (22.39%) and Spinosad (16.16%) as compared to control.
Similarly, the maximum per cent control in grain damage was recorded in Emamectin benzoate + Dimethoate (21.6%) followed by Chlorantraniliprole (16.8%), Dimethoate (16.1%), Emamectin benzoate + Acephate (13%), Azadirachtin (11.2%), Cyantraniliprole (11.1%) and Spinosad (4.5%) as compared to control (Table 3).
During
kharif 2021, the pod damage was recorded 16.29% to 39.81%. The minimum pod damage 16.29% was recorded in Emamectin benzoate + Dimethoate followed by Chlorantraniliprole with 19.59% pod damage and maximum pod damage 39.81% was recorded from untreated plots (Table 3). The Emamectin benzoate + Dimethoate was statistically at par with Chlorantraniliprole and Dimethoate, whereas, statistically superior over rest of the treatments. Azadirachtin, Emamectin + Acephate and Cyantraniliprole were at par with each other, whereas, these treatments were superior over spinosad. All the chemicals were significantly superior over control in reducing the pod damage (Table 3).
The grain damage range was recorded 11.41% to 30.04%. The minimum grain damage was 11.41% recorded in treatment Emamectin benzoate + Dimethoate followed by treatment Chlorantraniliprole with 15.85% grain damage, Dimethoate with 16.84% grain damage and maximum grain damage 30.04% was recorded from untreated plots (Table 3). Whereas, the Chlorantraniliprole, Dimethoate and Emamectin benzoate + Acephate were at par with each other. Azadirachtin and Cyantraniliprole were at par with each other. All the treatments were significantly superior over control in reducing the grain damage (Table 3).
Maximum per cent control in pod damage was recorded in treatment Emamectin benzoate + Dimethoate (59.08%) followed by Chlorantraniliprole (50.79%), Dimethoate (45.42%), Emamectin benzoate + Acephate (42.58%), Azadirachtin (38.99%), Cyantraniliprole (36.42%) and Spinosad (26.38%) as compared to control.
Similarly, the maximum per cent control in grain damage was recorded in Emamectin benzoate + Dimethoate (62.02%) followed by Chlorantraniliprole (47.24%), Dimethoate (43.94%), Emamectin benzoate + Acephate (33.95%), Azadirachtin (26.86%), Cyantraniliprole (24.43%) and Spinosad (21.94%) as compared to control (Table 3).
This result is corroborated by
Sharma et al., (2011) Emamectin benzoate 5 SG in combination with Acetamiprid 20 SP or Dimethoate 30 EC gave higher grain yield of 1399 and 1392 kg/ha, respectively and minimum grain damage by virtue of pod fly. Sonune
et al., (2018) also reported Emamectin benzoate was significantly superior to Chlorantraniliprole. However, Khinchi and Kumawat (2021) observed the use of Chlorantraniliprole @150 ml/ha was the most effective to control pod fly in pigeon pea crop.
Yield of pigeon pea
Among the treatments significantly the highest yield was recorded in Emamectin benzoate + Dimethoate (26.98 q/ha) and it was significantly at par with Chlorantraniliprole (25.65 q/ha) and Dimethoate (24.70 q/ha) during
kharif 2020. The treatment Emamectin benzoate + Acephate (23.33 q/ha) were significantly at par with Cyantraniliprole (22.63 q/ha), Azadirachtin (22.37 q/ha) and Spinosad (20.67 q/ha). However, all the treatments are significantly over the control (Table 4). The per cent increase in yield was maximum in Emamectin benzoate + Dimethoate (76%) followed by Chlorantraniliprole (68.06%) as compared to control (Table 4).
During
kharif 2021, the highest yield was recorded in Emamectin benzoate + Dimethoate (20.25 q/ha) followed by Chlorantraniliprole (18.92 q/ha) and lowest yield was recorded in the control (12.30 q/ha). The treatment Emamectin benzoate + Dimethoate was significantly at par with Chlorantraniliprole and Dimethoate. The per cent increase in yield was maximum increased in Emamectin benzoate + Dimethoate (64.63%) followed by Chlorantraniliprole (53.82%) as compared to control (Table 4).
Cost-benefit ratio
The highest cost-benefit ratio was recorded with Dimethoate (1:10.41) followed by Azadirachtin (1:9.61), Emamectin benzoate + Dimethoate (1:9.51), Chlorantraniliprole (1:9.27), Emamectin benzoate + Acephate (1:8.51), Cyantraniliprole (1.6.17) and the was recorded with Spinosad (1:3.13) in
kharif 2020 (Table 4).
However, during 2022, the highest cost-benefit ratio was recorded with Emamectin benzoate + Dimethoate (1:6.56) followed by Chlorantraniliprole (1:6.01), Dimethoate (1:5.91), Emamectin benzoate + Acephate (1:4.64), Azadirachtin (1:3.88), Cyantraniliprole (1.3.13) and the was recorded with Spinosad (1:1.32) (Table 4).