Efficacy of different insecticides against aphid infesting Okra

Introduction

In India, vegetables have occupied the important place in human diet. Among different vegetables okra, (Abelmoschus esculentus L. Moench) belonging to Malvaceae family is an important annual vegetable crop widely cultivated round the year in India. The attack of sucking pest complex and mite pests is one of the significant factors limiting okra cultivation, they damage the crop by sucking cell sap and devitalise the plant. The sugary substance 'honey dew' secreted by sucking pests also causes major problem leads to reduction in photosynthetic activity of plant. In sucking pests' aphid, leafhopper, white fly, and mites pose a major threat to the okra production. Aphids is a major sucking pest causes heavy damage in okra, cause yellowing, stunted growth, curling and crinkling of leaves). Leaf hopper (Amrasca bigutulla bigutulla) is a very destructive pest. In the early stages of the crop, leaf hoppers are a significant pest that weaken and reduce yield by sucking sap from the plants. It was reported that failure to control them in the early stages resulted in a yield loss of 54.04%. (Chaudhary and Dadeech, 1989) [6] . As many as 72 species of insects have been recorded on okra (Srinivas Rao and Rajendran, 2003) [1] . Efficacy testing of different insecticides against Okra pests is useful for determining which insecticides are most effective in controlling pests, allowing for the development of more targeted and sustainable pest management strategies. These pesticidal solutions are easily available, easy to use and very effective than any other methods. Hence, an attempt is made to study the efficacy of the important insecticides against aphid infesting Okra.

Material and Method

A field experiment was laid out in Randomized Block Design in Summer season for the two successive years, i.e., 2023-24 and 2024-25 at Center Experiment Station, Wakawali running under Dr. Balasaheb Sawant Konkan Krishi Vidyapeeth, Dapoli to study Efficacy of different insecticides against aphid infesting Okra. Konkan bhendi genotype is planted at distance of 45 x 30 cm. Three foliar sprays of the insecticide treatments at fortnight interval were conducted initiating the first when sufficient pest incidence noticed at 30 th days after sowing. 500 liters of water per hectare was used as diluent to mix insecticides for foliar spray applications. Hand operated Knapsack Sprayer with hollow cone nozzle was used for foliar spray applications.

Method of recording observations

The observations were taken as a pre count before one day to spraying of experiment plot and one, three, seven, ten and fourteen days after spraying as post count. Observations of 14 th day were treated as pre count for next foliar spray application. The number of nymph and adults of aphid were recorded from three leaves (from top, middle and bottom) of selected plant for taking observations.

Results and Discussion

The observation of the aphid's population on the Okra was recorded one day before spraying and 1,3, 7, 10 and 14 days after each spray. Data recorded on aphids' population during Summer 2023-24 are presented in (

Summer 2024-25

The observation of the aphid's population on the Okra was recorded one day before spraying as pre count and 1,3, 7, 10 and 14 days after each spray. Data recorded on aphid population during Summer 2024-25 are presented in (Table 03)

Overall mean of three sprays

The minimum population of aphid was observed in T transformed value DAS-Days After Spraying T1 -Fenpropathrin 30% EC @ 0.33ml /lit T2 -Fluxametamide 10% w/w EC @ 0.8 ml / lit T3 -Tolfenpyrad 15% EC @ 2.00 ml / lit T4 -Chlorantraniliprole 09.30% +Lambda-Cyhalothrin 04.60 ZC @ 0.4 ml/ lit T5 -Emamectin benzoate 05% SG @ 0.27 gm / lit T6 -Azadirachtin (10000 ppm) @ 3.00 ml / lit T7 -Metarhizium anisopliae (Metschnikoff) @ 5.00 gm / lit T8 -Untreated control ) -SE± 0.12 0.07 0.07 0.08 0.11 0.17 0.10 0.16 0.12 0.10 0.10 0.12 0.15 0.12 0.08 0.09 0.04 -C.D at 5%

N. S 0.21 0.20 0.24 0.34 0.50 0.32 0.48 0.36 0.30 0.31 0.37 0.46 0.37 0.23 0.28 0.11 -* Figures in the parentheses are transformed value DAS-Days After Spraying T1 -Fenpropathrin 30% EC @ 0.33ml /lit T2 -Fluxametamide 10% w/w EC @ 0.8 ml / lit T3 -Tolfenpyrad 15% EC @ 2.00 ml / lit T4 -Chlorantraniliprole 09.30% +Lambda-Cyhalothrin 04.60 ZC @ 0.4 ml/ lit T5 -Emamectin benzoate 05% SG @ 0.27 gm /lit T6 -Azadirachtin (10000 ppm) @ 3.00 ml / lit T7 -Metarhizium anisopliae (Metschnikoff) @ 5.00 gm / lit ) transformed value DAS-Days After Spraying T1 -Fenpropathrin 30% EC @ 0.33ml /lit T2 -Fluxametamide 10% w/w EC @ 0.8 ml / lit T3 -Tolfenpyrad 15% EC @ 2.00 ml / lit T4 -Chlorantraniliprole 09.30% +Lambda-Cyhalothrin 04.60 ZC @ 0.4 ml/ lit T5 -Emamectin benzoate 05% SG @ 0.27 gm /lit T6 -Azadirachtin (10000 ppm) @ 3.00 ml / lit T7 -Metarhizium anisopliae (Metschnikoff) @ 5.00 gm / lit T8 -Untreated control

Three days after spraying (3 DAS):

The minimum population of aphid was observed in T 3 -Tolfenpyrad 15% EC (0.97/ three leaves / plant) which was found statistically at par with T 2 -Fluxametamide 10% w/w EC (1.83/ three leaves / plant). Next best treatment was observed T 4 -Chlorantraniliprole 09.30% +Lambda-Cyhalothrin 04.60 ZC (2.97/ three leaves / plant) which was found statistically at par with T 1 -Fenpropathrin 30% EC (3.67/ three leaves / plant) and T 6 -Azadirachtin (10000 ppm)

Conclusion

From the pooled results it is concluded that, the significant difference was found in aphid population among the treatments. The data recorded on overall mean of three sprays revealed that all the treatments recorded a significantly lower population of aphid than untreated control.

References

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