Research Article
Efficacy of Different Insectides on Tomato Fruit Borer Helicoverpa armigera
Division of Entomology, SKUAST-K, Srinagar, India
Sheikh Bilal
Regional Agricultural Research Station, Leh, India
Tomato is an important vegetable crop grown around the world occupying the daily food regime of a majority of people. Tomato fruit borer, Helicoverpa armigera is an important pest which causes considerable losses in quantity as well as quality of tomato fruits (Singh and Chahal, 1978; Tewari and Moorthy, 1984; Reddy and Zehr, 2004). The monetary loss due to this pest in India has been estimated over rupees one thousand crore per year (Jayaraj et al., 1994) and yield losses ranged from 14-100% on different crops. Due to its economic importance considerable amount of work has been done for its control by biological means but the biological means tried so far have not been successful because the larva is the damaging stage which bores and remains inside the tomato fruit. H. armigera has assumed such proportions in the country for the past decade, farmers and plant protection agencies of central and state governments of India have virtually become perplexed regarding its control which ultimately lead to an array of social, economical and political problems. In past decades unreasoned and systematic calendar spraying of chemical control on tomato has been replaced by integrated pest management in India. To improve upon this problem, the most commonly method for the control of this pest is to have a film of a insecticide over foliage and fruiting bodies (Dotkhile et al., 1992; Sharma et al., 1993). The main objective of study is the determination of the efficacy of six insecticides at farmer field against Helicoverpa armigera infesting tomato.
A field trial was laid out in district Srinagar at farmers field for two consecutive years during Kharif 2003 and 2004 on tomato, cv. Pusa Ruby in randomised block design with seven treatments in three repeats and the plot size measuring 3x3 m2, row to row and plant to plant distance was 75x50 cm.
Treatments
Various insecticides as per recommendations of Division of Entomology, SKUAST-K were evaluated against tomato fruit borer. The concentrations, their sources, trade names are given in Table 1 and a spray of these insecticides were applied at 35 days after transplanting.
Table 1: | List of insecticides used under field conditions |
Control plots were sprayed with water only. During each harvest, borer affected and healthy fruits from the tomato plants were counted on number basis and the percent fruit damage was calculated using the cumulative data of all the pickings. Observation on population of larvae plant-1 were recorded 10 days after insecticidal application from selected plants. Yield of marketable fruits from different treatments were taken on whole plot basis and converted into kg ha-1 and the per cent retrievable loss was calculated by the following formula:
Where, T stands yield from treated plot and C stands for yield from the controlled plot. Data was statistically analysed as per Dospekhov (1984).
Fruit Damage
All the insecticidal treatments were effective and significantly superior to control (Table 2). The per cent fruit damage in the treatments varied from 8.65 to 14.07 during 2003 and 6.80 to 14.50 during 2004. Imidacloprid at 0.03% treatment gave excellent control of tomato fruit borer on tomato followed by deltamethrin, fluvalinate and fenvalerate. Whereas two conventional insecticides viz., chlorpyriphos and endosulfan were though inferior than rest of the treatments but were quite effective than control.
Larval Population
In control, highest larval population was recorded during both the years and lowest larval population was recorded when tomato plants were sprayed with imidacloprid (0.03%) which was superior to rest of the treatments. Deltamethrin and fluvalinate were the next best treatments in reducing the larval population of tomato fruit borer.
Yield
Highest fruit yield was obtained from the treatments with imidacloprid followed by deltamethrin, fluvalinate and fenvalerate. Imidacloprid treated tomato plants recorded 86.67 and 88.23% increase in fruit yield over control during both the years. Fluvalinate and fenvalerate sprayed tomato plants were at par with each other at p = 0.05.
Retrievable Loss
Observations clearly revealed that retrievable loss was almost same in both the years by spraying imdacloprid, deltamethrin, fluvalinate and fenvalerate sprayed tomato plants avoided more than 30% loss.
Table 2: | Efficacy of different insecticides on fruit damage(%), larval population (plant-1), yield (kg ha-1) and retrievable loss (%) on the incidence of Helicoverpa armigera during consecutive years on tomato (cv. Pusa Ruby) |
Efficacy of insecticides is judged on the basis of its ability to protect the crop from the target pest to reduce the fruit damage, larval population and therefore directly resulted to increase in fruit yield and retrievable loss on tomato in different treatments. As expected and the observations revealed that higher the fruit damage, larval population during the season and yield decreased in turn. Data (Table 2) revealed that all the treatments were significantly superior to control at p = 0.05 and the present findings are in line with the Ulaganathan and Gupta (2004) and Lavekar et al. (2004) who reported that imidacloprid treatments was more effective against H. armigera. Further various synthetic pyrethyroids were found effective against this pest (Fitt, 1989; Puri, 1997). Therefore, it is contemplated that as compared to conventional insecticides (chlorpyriphos and endosulfan). Imidacloprid and synthetic pyrethyroids due to their quick knock down effect, low mammalian toxicity and longer persistence on the treated surface can safely be used in controlling the fruit borer infesting tomato (Mishra, 1986; Singh and Singh, 1990; Bhatt and Patel, 2002).
Hussain Reply
Why this paper is not in google scholar
Editor
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