Informatics Publishing Limited

N. Bakthavatsalam ¹, J. Vinutha ¹, P. Ramakrishna ¹, A. Raghavendra ¹, K. V. Ravindra ¹, A. Verghese ¹

Affiliations
1 ICAR-National Bureau of Agricultural Insect Resources, P. B. No. 2491, H. A. Farm Post, Bengaluru 560 024, IN

Abstract

Autodetection is an olfactory behavioural process where the females of some species respond to their own pheromonal blends. Through electroantennogram studies it has been proved that the gravid females of Helicoverpa armigera (Hubner) respond to their pheromone blend consisting of Z-11-hexadecenal and Z-9- hexadecenal in the ratio 97 : 3. Male antennae respond more strongly than virgin female antennae. However, antennae of gravid females elicit strong response than unmated males. Also, males showed strong responses in cross-wind flying in wind tunnel experiments, when sex pheromone blends were used. Virgin females and gravid females showed poor response in wind-tunnel studies. The ovipositional experiment where gravid females were allowed to oviposit in the presence and absence of pheromone odours indicated that there was no difference in the number of eggs laid. Through morphological studies, it has been proved that the females also possess sensilla trichoidea, destined to perceive the pheromone blends, though lesser in number than the males. These results support the hypothesis that autodetection of sex pheromones exists in females of H. armigera and is thought to function as a mechanism to induce dispersal under high population densities.

Keywords

Autodetection, Electroantennogram, Helicoverpa armigera, Oviposition, Synthetic Sex Pheromone.

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A. N. Shylesha ¹, S. K. Jalali ¹, Ankita Gupta ¹, Richa Varshney ¹, T. Venkatesan ¹, Pradeeksha Shetty ¹, Rakshit Ojha ¹, Prabhu C. Ganiger ², Omprakash Navik ¹, K. Subaharan ¹, N. Bakthavatsalam ¹, Chandish R. Ballal ¹, A. Raghavendra ¹

Affiliations
1 ICAR-National Bureau of Agricultural Insect Resources, H. A. Farm Post, Bellary Road, Hebbal, Bengaluru - 560024, Karnataka, IN
2 All India Coordinated Research Project on Small Millets, Univeristy of Agricultural Sciences, GKVK, Bengaluru - 560065, Karnataka, IN

Abstract

Occurrence of Spodoptera frugiperda (J. E. Smith) (Insecta: Lepidoptera: Noctuidae), commonly known as fall armyworm, in southern India is reported along with associated natural enemies. Severe damage was noticed in Chikkaballapur, Hassan, Shivamogga, Davanagere and Chitradurga during July-August 2018. The incidence ranged from 9.0 to 62.5 percent at various locations, maximum incidence was recorded in Hassan district followed by Chikkaballapur, Davanagere, Shivamogga and Chitradurga. Morphology and molecular based taxonomic tools were used for the identification of this pest. The GenBank accession number MH704433 of Chikkaballapur population was released on 1^st August, 2018 and Barcode obtained from BOLD System-ID: AGIMP054-18. The survey also revealed natural parasitism by egg parasitoids viz., Telenomus sp. (Hymenoptera: Platygastridae) and Trichogramma sp. (Hymenoptera: Trichogrammatidae), gregarious larval parasitoid, Glyptapanteles creatonoti (Viereck) (Hymenoptera: Braconidae) solitary larval parasitoid, Campoletis chlorideae Uchida (Hymenoptera: Ichneumonidae), and a solitary indeterminate larval-pupal (Hymenoptera: Ichneumonidae: Ichneumoninae) parasitoid. Spodoptera frugiperda is the first host record for G. creatonoti across the globe. Glyptapanteles creatonoti, being a well established parasitoid of various noctuids in India and Malaysia, was capable of parasitizing S. frugiperda. Besides these, other commonly found bioagents viz., Forficula sp. (Dermaptera: Forficulidae) and entomopathogenic fungus Nomuraea rileyi (Farl.) Samson was also collected in large numbers. We report the natural enemy complex of S. frugiperda for the first time from India. The electro physiological response of Indian population of S. frugiperda male adults to pheromone was established. The studies to manage this pest by any/all means are in progress.

Keywords

Karnataka, Maize, New Pest.

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M. Nagesh ¹, M. Balachander ¹, T. M. Shivalingaswamy ¹, J. Patil ¹, A. N. Shylesha ¹, A. Raghavendra ¹

Affiliations
1 ICAR-National Bureau of Agricultural Insect Resources, P. B. No. 2491, H. A. Farm Post, Bellary Road, Hebbal, Bangalore − 560 024, Karnataka, IN

Abstract

Variability in virulence among entomopathogenic nematodes, Heterorhabditis indica, H. bacteriophora and Steinernema abbasi, was studied for lethality, foraging behaviour in response to host volatiles, thermal requirements (degree-days), recyclability, persistence and field efficacy against Turfgrass Sod Webworm (TSW), Herpetogramma phaeopteralis. Comparatively, lethal concentration and time were lowest for H. indica against TSW. Recyclability of EPN ranged from 3.42 × 10⁵ to 4.23 × 10⁵ IJs g¹ of TSW. H. bacteriophora recorded highest movement rate on agar (0.38–0.78cm) and sand-agar (0.45–0.56cm), followed by S. abbasi, and H. indica. Responding to TSW volatiles, S. abbasi recorded maximum movement, H. bacteriophora, moderate, and H. indica, lowest. Heterorhabditis indica (with nictitation); S. abbasi and H. bacteriophora (without nictitation) were ambusher and cruiser, respectively. S. abbasi preferred warmer temperatures (30–33°C), H. bacteriophora, moderate (24–27°C), and H. indica, a wider range (24–30°C), for virulence based on thermal requirement. In field, EPNs were comparable to chlorpyriphos against TSW. We demonstrated the complementarity of thermal preferences of EPNs and insect pest was critical besides attributes like foraging behaviour, recyclability, persistence, and lethality values for their success in the field.

Keywords

Degree-Days, Foraging, Herpetogramma phaeopteralis, Heterorhabditis indica, H. bacteriophora, Sod Webworm, Steinernema abbasi, Thermal Requirement, Turfgrass, Virulence, Variability.

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