K. Sahayaraj ¹, S. Kartick Raja ¹

Affiliations
1 Crop Production Research Centre, St. Xavier's College Palayamkottai 627002, Tamil Nadu, IN

Abstract

The effect of biopesticides (Nivaar, Mealisac, Osaqua, Citropyne and Azadirachtin) and synthetic pesticide (cypermethrin) on egg hatchability, nymphal mortality and biological control potential of Rhynocoris marginatus on the cotton pest, Aphis gossypii was studied under laboratory condition. The biopesticides at specified concentrations did not affect the biological control potential of R. marginatus, however, its ovicidal property was evident.

Keywords

Aphis gossypii, Biological Control Potential, Biopesticides, Rhynocoris marginatus.

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K. Sahayaraj ¹, M. G. Paulraj ¹

Affiliations
1 Crop Protection Research & Extension Unit, Department of Zoology St. Xavier's College, Palayamkottai 627002, Tamil Nadu, IN

Abstract

A laboratory experiment was conducted to find out tbe excess proportion index (EPI) and frequency of prey location (rostrum protrusion) behaviourofa reduviid predator,Rhynocoris marginatus (Fabr.) to solvent extracts or three groundnut pests, Aproaerema modicella Dev., Helicoverpa annigera (Hiibner) and Spodoptera litultra (Fabr.), using six-arm glass olfactometers. Fourth, 5^th instar and adult stages or the predator were attracted by all the larval extracts. The frequency of prey location behaviour was high to S. litura larval extracts for fourth (10.43 minutes), fifth (12.07 minutes) instar nymphs and adults (15.38 minutes) of the predator, though statistically not significant. In general, adult predators exhibited high frequency of prey location behaviour for all the tested pests.

Keywords

Aproarema modicella, Helicoverpa armigera, Prey Location, Rhynocoris marginatus, Spodoptera litura.

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K. Sahayaraj ¹, Dunston P. Ambrose ¹

Affiliations
1 Entomology Research Unit St. Xavier's College, Palayankottai - 627 002, IN

Abstract

The host and stage preference of Acanthaspis pedestris Stal an important reduviid predator of many insect pests in South India were studied using four cotton pests, such as Earias insulana Boisdual, Helicoverpa armigera (Hubner), Pectinophora gossypiella Saunders and Spodoptera litura (Fabricius). The functional response was also studied on P. gossypiella, The results revealed that medium sized larvae were preferred in case of E. insulana (78.87 %), H. armigera (83.33%) and S. Litura (66.66%) while in case of P. gossypiella (75.0 %), only larger larvae were preferred by the predator. The bug preferred P.gossypiella (31.28%) to H. armigera (29.74%). Functional response showed a linear relationship between the number of prey offered and the number consumed. The females were found to be better predators than the males.

Keywords

Acanthaspis pedestris, Biocontrol Agent, Cotton Pests, Earias insulana , Helicoverpa armigera , Pectinophora gossypiella, Spodoptera litura, Host and Stage Preference, Functional Response.

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Dunston P. Ambrose ¹, K. Sahayaraj ¹

Affiliations
1 Entomology Research Unit, Department of Zoology, St. Xavier's College, Palayankottai - 627 002, IN

Abstract

Predatory potential and stage preference of the reduviid predator,
Allaeocranum quadrisignatum Reuter were studied under laboratory
conditions. The total developmental period on an average was 84.06 days. The younger nymphal instars (I to III) of the predator consumed lesser number of prey than the older (IV & V) nymphal instars. The predatory rate gradually increased as the nymphal development progressed. The nymphs and adults preferred the I and II instar nymphs respectively of Dysdercus cingulatus Fabricius.

Keywords

Allaeocranum quadrisignatum, Dysdercus cingulatus, Predatory Potential, Stage Preference.

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