S. S. Navi ¹, S. Lingappa ¹, R. K. Patil ¹

Affiliations
1 Department of Entomology, University of Agricultural Sciences, Dharwad, 580 005, Karnataka, IN

Abstract

An investigation was carried out during 2007-08 at Department of Agricultural Entomology, University of Agricultural Sciences, Dharwad to evaluate new molecules of insecticides against the predatory brown lacewing, Micromus igorotus Banks in laboratory conditions. Insecticides showed distinct deleterious effect on different life stages of M. igorotus. Emamectin benzoate was highly toxic to all the stages of the predator by recording least LC₅₀ values ranging from 0.001032-0.00314. Thiodicarb was the least toxic to eggs (LC₅₀: 0.159262) and grubs (LC₅₀: 0.007240), profenophos was safe to pupa (LC₅₀: 0.026570), while indoxacarb was 505050 the safest to adult (LC₅₀: 0.003115). Relative toxicity of chemicals when compared to their field concentration against target pest revealed that safety margin was the lowest for profenophos to eggs and grubs, followed by methomyl. Among the insecticides tested, emamectin benzoate was highly toxic to all stages of M. igorotus, while thiodicarb was the least toxic to eggs and larval stages, however, profenophos and indoxacarb were the least toxic to pupae and adults, respectively.

Keywords

New Molecule, Insecticides, Micromus igorotus, Toxicity.

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V. Rachappa ¹, S. Lingappa ², R. K. Patil ²

Affiliations
1 Agricultural Research Station, Malnoor 585215, Gulbarga District, Karnataka, IN
2 Department of Entomology, University of Agricultural Sciences, Dharwad 580005, Karnataka, IN

Abstract

An attempt was made to know the variation in field collected isolates of Metarhizium anisopliae (Metschnikoff) Sorokin under laboratory conditions. Isolates of M. anisopliae collected from different geographical regions were studied for various parameters like growth and sporulation on potato dextrose agar (PDA) medium and rice based medium, and exhibited considerable variation. Ma3 and Ma4 isolates took 6 days to initiate sporulation while Ma1 and Ma2 isolates took 2 to 3 days on PDA. Mycelial growth in Ma1 and Ma2 isolates, being on par, was significantly higher (38.60 and 42.30 mm, respectively) than the other two isolates (Ma3-32.30 mm and Ma4- 33.19 mm). Ma1 and Ma2 isolates grew faster on rice based medium and yielded conidial yield of 8.93 and 9.32 g per 100 g of medium respectively. Isolate Ma2 was the most virulent against Helicoverpa armigera (Hübner) and Plutella xylostella (Linnaeus) with less LC₅₀ values of 1.77 x 10⁶ and 1.98 x 106 conidia per ml followed by Ma1, which was more virulent against Oryctes rhinoceros (Linnaeus). The lethal time (LT₅₀) was low in Ma2 for H. armigera and P. xylostella (126.15 h and 69.74 h, respectively) in contrast to Ma1 that recorded lower LT₅₀ value against O. rhinoceros (294.47h). The results indicate that Ma2 was the best isolate against lepidopteran insects and Ma1 was the best against coleopterans.

Keywords

Bio-Efficacy, Biological Characters, Helicoverpa armigera, Metarhizium anisopliae, Oryctes rhinoceros, Plutella xylostella.

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M. Vidya ¹, R. K. Patil ¹, G. K. Ramegowda ¹, S. Lingappa ¹

Affiliations
1 Department of Agricultural Entomology, University of Agricultural Sciences, Dharwad- 580 005, Karnataka, IN

Abstract

Studies were made to explore the potentiality of Micromus igorotus for the management of aphids in cotton (Aphis gossypii G.), sorghum (Metanaphis sachari Zehntner) and safflower (Uroleucon carthami Theo.) ecosystems during November 2004-December 2005 at main Agricultural Research Station, University of Agricultural Sciences, Dharwad, Karnataka, India. Post-release observations revealed the presence of a mixture of brown lacewing larvae distinctly different from that of M. igorotus in cotton and sorghum ecosystems. These were identified as Micromus australis Hagen and Micromus timidus Hagen occurence of M. australis in cotton and sorghum ecosystems and on the prey aphids constitutes a new record.

Keywords

Cotton, Ecosystem, Micromus australis, Sorghum.

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M. Vidya ¹, S. Lingappa ¹, R. K. Patil ¹, G. K. Ramegowda ¹

Affiliations
1 Department of Agricultural Entomology, University of Agricultural Sciences, Dharwad- 580 005, Karnataka., IN

Abstract

Biology and feeding potential of Micromus australis Hagen (Neuroptera: Hemerobiidae) was studied under laboratory conditions on Melanaphis sacchari (Zehntner), The predator was observed to pass through three larval instars. On an average first, second and third instars lasted for 2.00 ± 0.0, 1.35 ± 0.49 and 1.76 ± 0.44 days and consumed 58.82 ± 9.68, 67.47 ± 24.56 and 96.18 ± 20.15 aphids, respectively. The fecundity was 818.90 ± 331.81 eggs/female. The individual larvae consumed 213.18 ± 21.95 aphid nymphs to complete the larval duration (5.12 ± 0.49 days) and an adult consumed on an average 585,24 ± 120.49 aphid nymphs over a period of 41.75 ± 11.36 days. Per day consumption of the aphids was 41.82 ± 4.18 and 14,02 ± 9.41 by larva and adult, respectively.

Keywords

Hemerobiidae, Micromus igorotus, Biology, Feeding Potential, Micromus Sp.

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M. S. Puttannavar ¹, R. K. Patil ¹, M. Vidya ¹, G. K. Ramegowda ¹, S. Lingappa ¹, Shekarappa ¹, K. A. Kulkarni ¹

Affiliations
1 Department of Agricultural Entomology, College of Agriculture University of Agricultural Sciences Dharwad 580 005, Karnataka, IN

Abstract

A laboratory study was carried out on biology of sugarcane woolly aphid (SWA) predator, Dipha aphidivora Meyrick (Lepidoptera: Pyralidae). Dipha aphidivora occupied 5.6 ± 0.81, 24.61 ± 3.41, 7.80 ± 0.51, 1.65 ± 0.54 and 3.89 ± 0.74 days for incubation. total larval period, pupation, longevity of adult male and female, respectively. The total life cycle lasted for 43.27 ± 5.84 days. During its total larval period of 24.61 ± 3.41 days, a single D.aphidivora consumed on an average 6,074.84 ± 87.6 sugarcane woolly aphids.

Keywords

Biology, Dipha aphidivora, Sugarcane Woolly Aphid.

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C. S. Patil ¹, S. Lingappa ¹

Affiliations
1 Department of Agricultural Entomology University of Agricultural Sciences Dharwad 580005, Karnataka, IN

Abstract

Studies were conducted to assess toxicity of promising insecticides against tobacco aphid, M. nicotianae and its predator, C. Sexmaculata during 1995 at the Agricultural Research Station, Nipani (Karnataka). The selectivity ratio of M. nicotianae and C. sexmaculata grubs and adults was lowest for acepbate followed by imidacloprid and oxydemeton methyl. However, endosulfan registered highest selectivity ratio and it could be used for aphid control along with the coccinellids in an integrated approach.

Keywords

Insecticides, Cheilomenes sexmaculata, Myzus nicotianae, Selectivity.

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C. S. Patil ¹, S. Lingappa ²

Affiliations
1 Department of Entomology, MPKV, Rahuri, Maharashtra, IN
2 Department of Agricultural Entomology, University of Agricultural Sciences, Dharwad 580 005, Karnataka, IN

Abstract

Persistent toxicity of insecticides to Cheilomenes sexmaculata (Fabricius) was studied during 1994-95. Acephate, imidacloprid and carbosulfan exhibited considerable indirect toxic effect on the population of C. sexmaculata. However, oxydemeton methyl was relatively safe to C. sexmaculata.

Keywords

Cheilomenes sexmaculata, Insecticides, Myzus nicotianae, Persistent Toxicity.

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K. Basavana Goud ¹, S. Lingappa ¹, K. A. Kulkarni ¹

Affiliations
1 Department of Agricultural Entomology, University of Agricultural Sciences, Dharwad 580005, Karnataka, IN

Abstract

Larvae of cotton bollworm, Helicoverpa armigera (Hiibner) resistant and susceptible to fenvalerate and endosulfan were tested for susceptibility to a nuclear polyhedrosis virus. The LC₅₀ values were less in resistant strains than in susceptible. The resistance ratio to HaNPV was highest in fenvalerate resistant strain (0.88) followed by endosulfan resistant (0.64) strain.

Keywords

HaNPV, Helicoverpa armigera, Insect Resistance.

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