S. S. Hussaini ¹, V. Shakeela ¹, M. H. Dar ¹

Affiliations
1 P. B. No. 2491, H. A. Farm Post, Bellary Road Hebbal, Bangalore, 560 024, Karnataka, IN

Abstract

Effect of different temperatures on infectivity and progeny production of indigenous entomopathogenic nematode isolates, Steinernema carpocapsae PDBC EN 6.11, S. abbasi PDBC EN 3.1, S.tami PDBC EN 2.1, and Heterorhabditis indica PDBC EN 6.71, PDBC EN 13.3 were studied under laboratory condition against Galleria mellonella (Linnaeus) and Agrotis ipsilon (Hufnagel) final instar larvae. All isolates caused absolute mortality of test insect larvae, and produced progeny at 25 and 32°C. Low rate of infection or no infection was observed at lower temperatures, 15 and 8°C, respectively. Time required to kill host insects by all isolates showed difference at 15, 25 and 32°C. Shortest time for mortality of A. ipsilon and G. mellonella larvae was observed at 32°C followed by 25°C. Absolute mortality of larvae was observed with all isolates after 48 and 72 hours at 25° and 32°C, whereas the same was not achieved at 15°C even after 96 hours post exposure. Progeny production of all isolates varied with reference to temperature. Irrespective of isolates, 25°C was found suitable for infection and development of nematode populations.

Keywords

Agratis ipsilon, Entomopalhogenic Nematodes, Galleria mellonella, Heterorhabditis indica, Steinernema abbasi, S. carpocapsae, S. tami, Temperature.

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M. H. Dar ¹, R. Q. Rizvi ¹, H. Saxena ², N. A. Naqvi ¹

Affiliations
1 Department of Plant Protection, Aligarh Muslim University, Aligarh, 202 002, U. P., IN
2 Division of Crop Protection, Indian Institute of Pulses Research (ICAR), Kanpur, 208024, U.P., IN

Abstract

Three parasitoids, viz. Ormyrus orientalis Walker, Euderus agromyzae Gangrade and Eurytoma ranjithi Narendran were found parasitzing podfly, Melanagromza obtusa (Malloch) on all the three cultivars of pigeonpea. Parasitization increased with the increase in pest population irrespective of the parasitoid species. Ormyrus orientalis was recorded as the key parasitoid. There was a significant effect of resistant and susceptible varieties on parasitization of podfly. The mean parasitization by all the three species in 2000-01 was 24.0 per cent on NA1 followed by Bahar (22.5%) and SL12-1 (8.4%). Similarly, in the following year, the mean parasitization was 25.0 per cent on NA1 which was on par with Bahar (24.3%) but significantly superior (p=0.05) to SL12-1 (9.3%). A distinct variation in the population of pest, Melanagromyza obtusa with respect to pigeonpea cultivars was observed, however, the oviposition trend recorded at weekly interval was found almost same. The average oviposition was 14-15 per cent in case of the susceptible varieties (Bahar and NA1) whereas; the resistant variety SL12-1 exhibited only 4 per cent oviposition by podfly. The results clearly indicated that greater parasitism of M. obtusa occurred on susceptible genotypes than resistant cultivar.

Keywords

Euderus agromyzae, Eurytoma ranjithi, Ormyrus orientalis, M. Obtusa, Pigeonpea.

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