Informatics Publishing Limited

Madhulika Srivastava ¹, A. V. N. Paul ¹, Prem Dureja ², A. K. Singh ³

Affiliations
1 Division of Entomology, IARI, New Delhi, 110012, IN
2 Division of Agricultural Chemicals, IARI, New Delhi, 110012, IN
3 Department of Zoology, Delhi University, Delhi, 110007, IN

Abstract

Kairomones emanating from males and females of three different host insects, viz., Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae) Spodoptera exigua (Hubner) (Lepidoptera: Noctuidae) and Chilo auricilius (Dudgeon) (Crambidae: Lepidoptera) that tend to influence the parasitic potential of Trichogramma chilonis Ishii was studied. Whole body extracts of male and female moths were analysed separately by gas liquid chromatography for determining their hydrocarbon profile, which showed the presence of straight chain saturated hydrocarbons ranging from C₉ to C₅₀, Different host insects showed variation in number and concentration of these chemicals, which were responsible for influencing parasitoid activity and parasitism. The concentration of these hydrocarbons ranged from 4 ppm to 1215280 ppm. The foraging activity of the parasitoid as indicated by parasitoid activity index (PAI) was highest (14.63) in S. exigua female body extract at highest concentration (60, 0000 ppm). Per cent mean parasitism rates recorded for S. litura male and S. exigua male and female body extract were significantly different from that for the body extract of C. auricilius. Both kairomonal interactions observed in the male body extract of S. litura could be due to the presence of appreciably very high amounts of favourable hydrocarbons docosane and heneicosane and comparatively high amount of octosane and pentaeosane as compared to its female body extract. Similarly, female body extract of S. exigua also showed comparatively higher amounts of favourable hydrocarbons tricosane, docosane, pentacosane, heneicosane and hexacosane as compared to its male body extract. Based on the hydrocarbon profile of body washings of males and females of the three host insects and quantity of favourable and unfavourable hydrocarbons present in individual extract body, it may be coneluded that heneicosane and hexacosane exerted significantly higher level of kairomonal effect on the parasitoid as compared to other hydrocarbons. The response elicited by the male extract body of S. litura was significantly higher, whereas the body extract of male C. auricilius elicited the least response from T. chilonis. These favourable hydrocarbons at the appropriate concentration of body extract of spent adults of S. litura males and S. exigua females could be used for enhancing parasitization by T. chilonis.

Keywords

Chilo auricilius, Host Body Extract, Kairomones, Spodoptera exigua, S. litura, Trichogramma chilonis.

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K. M. Sreekumar ¹, A. V. N. Paul ²

Affiliations
1 College of Agriculture, Padannakkad, Kasaragod 671328, Kerala, IN
2 Division of Entomology, Indian Agricultural Research Institute, New Delhi 110012, IN

Abstract

An illumination chamber and a parasitization chamber was designed and modified for the mass multiplication of the egg parasitoid, Trichogramma brasiliense Ashmead on Corcyra cephalonica (Stainton) egg cards. The illumination chamher maintained a light intensity of 100.3 lux and a maximnm and minimum temperature of 29 and 24° respectively, at the centre. The parasitization chamber consisted of a glass hox witb eight wire mesb supports inside to keep the egg cards. Placing two parasitization chambers inside the illumination chamber, 21 rnl of eggs could be exposed for parasitization at a time resulting in uniform parasitization of eggs. No specific pattern in parasitization was perceived between the layers of tbe chamber at different ratios and exposures. Estimation of egg parasitization at 4 selected locations constituting 0.22 per cent of tbe total area of the egg card was found ideal for sampling tbe level of overall parasitization in the egg cards. Exposure of mother to daughter cards in the ratio of 1:7 for 48 h in tbe parasitization chamber resulted in the optimum parasitization of the eggs by the parasitoid, higher percentage of adult emergence and less number of runts in the resultant progeny.

Keywords

Egg Parasitization, Illumination Chamber, Parasitization Chamber, Runts, Trichogramma brasiliense.

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K. M. Sreekumar ¹, A. V. N. Paul ¹, D. V. K. Samuel ¹

Affiliations
1 Division of Entomology Indian Agricultural Research Institute, New Delhi 110012, IN

Abstract

A machine for making Corcyra egg cards was designed, fahricated and evaluated for labour efficient mass production of Trichogramma egg cards. The machine could paste on an average 9.97 ml of eggs per minute compared to 0.7 ml in the manual method. The number of eggs pasted per 0.25 sq cm of the card varied from 32 to 145 eggs with an average of 73 eggs for machine made cards whereas the corresponding values for manually made cards were 45, 118 and 76.65, respectively. The average number of egg cards produced per hour in the machine operated system was 14.3 times higher when compared to the manual system. The machine is provided with an in-built UV chamber for the sterilization and inactivation of the host eggs. The cost of the machine works out to be about Rs.20, 000 per unit and this is the first report of a machine developed for host egg card preparation from India.

Keywords

Corcyra cephalonica, Egg Card Making Machine, Mass Production, Trichogramma.

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