Efficacy of different botanicals and insecticide against leaf eating caterpillar (Carea Subtilis) on jamun (Syzygium Cuminii L.)

Introduction

Jamun (Syzygium cuminii L.) is an important fruit crop belonging to the family Myrtaceae and is valued for its edible fruits and medicinal and nutritional properties. The crop is cultivated in different parts of India and has considerable importance in fruit production as well as traditional health uses. Several insect pests are associated with jamun and may affect foliage, flowers and fruits. Among the foliage-feeding insects, the leaf eating caterpillar (Carea subtilis) is an important pest because larval feeding damages the leaf lamina and reduces the effective photosynthetic area. Severe infestation can adversely affect plant growth and fruit production. Management of foliage-feeding insect pests in perennial fruit crops requires effective and timely suppression while considering the use of botanicals and microbial biopesticides. Neem oil, karanj oil, mahua oil, neem seed kernel extract (NSKE) and Bacillus thuringiensis are potential alternatives for pest management, whereas insecticides such as lambda-cyhalothrin may provide rapid suppression. Therefore, the present investigation was undertaken to evaluate the efficacy of selected botanicals, biopesticide and insecticide against leaf eating caterpillar on jamun under field conditions.

Materials and Method

The field experiment was conducted in a nine-year-old jamun orchard of the variety 'Kokan Bahadoli' at the Research Farm, College of Agriculture, Badnapur, during 2025-26. The orchard was maintained without application of insecticides during the seasonal incidence observations and recommended agronomical practices were followed. For the management experiment, the treatments were evaluated in a Randomized Block Design (RBD) with seven treatments and three replications.

Imposition of treatments

Three sprays were applied at an interval of 15 days. The selected treatments were applied at their respective recommended experimental doses, while T 7 was maintained as an untreated control.

Observations were recorded before and after each spray.

Method of observations

Observations on leaf eating caterpillar (Carea subtilis) were recorded from four randomly selected branches of uniform length (1.5 ft each) representing the top, middle and bottom canopy of each experimental tree. Observations were recorded one day before spraying (1 DBS) and after each spray. The total number of healthy and damaged leaves was counted and the percentage of leaf damage was calculated as follows: Number of damaged leaves Per cent damage = X 100 Total number of observed leaves The treatment data were subjected to analysis of variance (ANOVA) appropriate for a Randomized Block Design (RBD) following Gomez et al. (1984) [1] . Treatment means were compared using the Critical Difference (CD) at the 5 per cent level of significance. The values in parentheses in the efficacy table are arcsine transformed values.

Results and Discussion

The pooled efficacy of three consecutive sprays of the evaluated treatments against leaf eating caterpillar on jamun is presented in Table 3. The treatments differed in their efficacy and a progressive reduction in leaf infestation was observed across the successive spray means in most treatments.

Figures in parentheses are

First spray application

After the first spray, lambda-cyhalothrin 5% EC @ 1.0 ml/litre (T 6 ) recorded the lowest mean leaf infestation of 7.11 per cent (15.46), indicating the highest efficacy among the treatments. It was followed by NSKE 5% @ 50 g/litre (T 5 ) with 10.06 per cent (18.49), neem oil @ 2.0 ml/litre (T 1 ) with 11.53 per cent (19.85), Bacillus thuringiensis @ 2.0 g/litre (T 4 ) with 12.40 per cent (20.62), karanj oil @ 2.0 ml/litre (T 2 ) with 13.14 per cent (21.25), and mahua oil @ 2.0 ml/litre (T 3 ) with 14.23 per cent (22.16). The untreated control recorded the highest infestation of 18.31 per cent (25.33).

Second spray application

Following the second spray, T 6 continued to be the most effective treatment and recorded the lowest leaf infestation of 6.49 per cent (14.76). T 5 recorded 7.62 per cent (16.02), followed by T 1 (8.93 per cent), T 4 (9.80 per cent), T 2 (10.66 per cent) and T 3 (11.69 per cent). The untreated control recorded the highest infestation of 16.91 per cent (24.28).

Third spray application

After the third spray, the lowest infestation was again recorded in T 6 , lambda-cyhalothrin 5% EC @ 1.0 ml/litre, with 5.94 per cent (14.11).

It was followed by T 5 (6.72 per cent), T 1 (7.29 per cent), T 4 (8.15 per cent), T 2 (8.81 per cent) and T 3 (10.13 per cent). The untreated control recorded the highest infestation of 16.04 per cent (23.61).

Pooled mean

The pooled mean of three consecutive sprays clearly demonstrated the superiority of lambda-cyhalothrin 5% EC @ 1.0 ml/litre (T 6 ), which recorded the lowest pooled leaf infestation of 6.51 per cent (14.78). NSKE 5% @ 50 g/litre (T 5 ) ranked second with 8.13 per cent (16.57), followed by neem oil @ 2.0 ml/litre (T 1 ) with 9.25 per cent (17.71). Bacillus thuringiensis @ 2.0 g/litre (T 4 ) recorded 10.12 per cent (18.55), while karanj oil @ 2.0 ml/litre (T 2 ) and mahua oil @ 2.0 ml/litre (T 3 ) recorded 10.87 per cent (19.25) and 12.02 per cent (20.29), respectively. The untreated control recorded the highest pooled infestation of 17.09 per cent (24.42). The consistent superiority of T 6 across all three sprays indicates that lambda-cyhalothrin 5% EC provided the most effective suppression of leaf eating caterpillar under the conditions of the present experiment. Among the non-chemical options, NSKE 5% and neem oil showed comparatively better performance than the other evaluated botanicals and biopesticide.

Conclusion

The field evaluation demonstrated that the tested treatments differed in their efficacy against leaf eating caterpillar on jamun. Lambda-cyhalothrin 5% EC @ 1.0 ml/litre recorded the lowest infestation after the first, second and third sprays and also recorded the lowest pooled infestation of 6.51 per cent (14.78). Among the botanicals and biopesticide, NSKE 5% @ 50 g/litre and neem oil @ 2.0 ml/litre were comparatively more effective. Therefore, lambda-cyhalothrin 5% EC @ 1.0 ml/litre was the most effective treatment in the present field evaluation, followed by NSKE 5% and neem oil.

References

1. Gomez KA, Gomez AA. Statistical Procedures for Agricultural Research. John Wiley & Sons; 1984.
2. Haldhar SM, Berwal MK, Samadia DK, Kumar R, Gora JS, Choudhary S. Biochemical basis of plant-insect interaction in arid horticulture crops: a scientific review. Journal of Agriculture and Ecology. 2018;6:1-16.
3. Kumar R, Ramamurthy VV, Sharma G. Checklist of insects associated with Jamun (Syzygium cuminii Skeels) from India. Biological Forum: An International Journal. 2010;2:1-5.
4. Sehwag S, Das M. Nutritive, therapeutic and processing aspects of Jamun, Syzygium cuminii (L.) Skeels-An overview. Indian Journal of Natural Products and Resources. 2014;5(4):295-307.
5. Singh S, Singh AK, Singh HP, Pagle BG, More TA. Jamun booklet. ICAR, New Delhi; 2011:1-46.
6. Warrier PK. Indian medicinal plants: a compendium of 500 species. Vol. 5. Orient Blackswan; 1993.