Latest News on Helicoverpa Armigera Research: Dec – 2019

Management of pyrethroid and endosulfan resistance in Helicoverpa armigera (Lepidoptera: Noctuidae) in Australia.

This issue is dedicated to various aspects of an insecticide resistance management (IRM) strategy introduced into the summer rainfall cropping areas of eastern Australia within the 1983-84 season. The aims of this strategy were to manage pyrethroid and endosulfan resistance problems in Helicoverpa armigera, and to avoid any possible future problems with organophosphate or carbamate resistance. the difficulty is arranged within the following sections: the Australian insecticide resistance management strategy; evaluation of the impact of the strategy on pyrethroid and endosulfan resistance: discriminating dose studies; evaluation of the impact of the strategy on pyrethroid resistance: F1 analyses; pyrethroid and endosulfan resistance: selection and cross resistance studies; pyrethroid and endosulfan resistance: biology of resistant and susceptible larvae and pupae; pyrethroid resistance: field selection in sorghum; pyrethroid resistance: selection of adults; pyrethroid resistance: field resistance mechanisms; pyrethroid resistance: synergists; and pyrethroid resistance: resistance breaking pyrethroids. [1]

The sequence of the Helicoverpa armigera single nucleocapsid nucleopolyhedrovirus genome

The nucleotide sequence of the Helicoverpa armigera single-nucleocapsid nucleopolyhedrovirus (HaSNPV) DNA genome decided and analysed. The circular genome encompasses 131403 bp, features a G+C content of 39•1 mol% and contains five homologous regions with a singular pattern of repeats. Computer-assisted analysis revealed 135 putative ORFs of 150 nt or larger; 100 ORFs have homologues in Autographa californica multicapsid NPV (AcMNPV) and an extra 15 ORFs have homologues in other baculoviruses like gypsy moth MNPV (LdMNPV), Spodoptera exigua MNPV (SeMNPV) and Xestia c-nigrum granulovirus (XcGV). Twenty ORFs are unique to HaSNPV without homologues in GenBank. Among the six previously sequenced baculoviruses, AcMNPV, domestic silkworm moth NPV (BmNPV), Orgyia pseudotsugata MNPV (OpMNPV), SeMNPV, LdMNPV and XcGV, 65 ORFs are conserved and hence are considered as core baculovirus genes. The mean overall aminoalkanoic acid identity of HaSNPV ORFs was the very best with SeMNPV and LdMNPV homologues. [2]

Pyrethroid resistance mechanisms in Australian Helicoverpa armigera

In 1983, at the onset of pyrethroid resistance in Australian Helicoverpa armigera, three resistance mechanisms were identified. They were: a robust nerve insensitivity (Super‐Kdr), penetration resistance (Pen), and an element which was overcome by piperonyl butoxide (PBO). Super‐Kdr nerve insensitivity seemed to be a serious explanation for pyrethroid resistance and contributed to high‐order resistance (> 100‐fold). From 1987 to 1990, to watch the effect of the Australian Helicoverpa insecticide resistance management strategy on insecticide resistance, we conducted a survey of the frequencies of those mechanisms in field‐collected H. armigera. The relative importance of the Pen and Pbo mechanisms in resistant H. [3]

Multiple incursion pathways for Helicoverpa armigera in Brazil show its genetic diversity spreading in a connected world

The Old World corn earworm Helicoverpa armigera was first detected in Brazil with subsequent reports from Paraguay, Argentina, Bolivia, and Uruguay. This pattern suggests that the H. armigera spread across the South American continent following incursions into northern/central Brazil, however, this hypothesis has not been tested. Here we compare northern and central Brazilian H. armigera mtDNA COI haplotypes with those from southern Brazil, Uruguay, Argentina, and Paraguay. We infer spatial genetic and gene flow patterns of this dispersive pest within the agricultural landscape of South America. [4]

Seasonal Incidence of Gram Pod Borer, Helicoverpa armigera (Hübner) and Tur Pod Fly, Melanagromyza obtusa (Malloch) on Late Maturing Pigeonpea in Varanasi Region of Indo-Gangetic Plain

Aim: to review the seasonal incidence pattern of gram pod borer, Helicoverpa armigera (Hübner) and tur pod fly, Melanagromyza obtusa (Malloch) in pigeonpea ecosystem.

Study Design: Complete Randomized Block Design.

Place and Duration of Study: Field experiments were conducted at Agriculture Research Farm, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi during Kharif seasons of 2015-16 and 2016-17. [5]

Reference

[1] Forrester, N.W., Cahill, M., Bird, L.J. and Layland, J.K., 1993. Management of pyrethroid and endosulfan resistance in Helicoverpa armigera (Lepidoptera: Noctuidae) in Australia. Management of pyrethroid and endosulfan resistance in Helicoverpa armigera (Lepidoptera: Noctuidae) in Australia., (Supplement No. 1). (Web Link)

[2] Chen, X., IJkel, W.F., Tarchini, R., Sun, X., Sandbrink, H., Wang, H., Peters, S., Zuidema, D., Lankhorst, R.K., Vlak, J.M. and Hu, Z., 2001. The sequence of the Helicoverpa armigera single nucleocapsid nucleopolyhedrovirus genome. Journal of General Virology, 82(1), (Web Link)

[3] Gunning, R.V., Easton, C.S., Balfe, M.E. and Ferris, I.G., 1991. Pyrethroid resistance mechanisms in Australian Helicoverpa armigera. Pesticide Science, 33(4), (Web Link)

[4] Multiple incursion pathways for Helicoverpa armigera in Brazil show its genetic diversity spreading in a connected world
Jonas Andre Arnemann, Stephen Roxburgh, Tom Walsh, Jerson Guedes, Karl Gordon, Guy Smagghe & Wee Tek Tay
Scientific Reports volume 9, (Web Link)

[5] Keval, R., Khamoriya, J., Chakravarty, S. and Ganguly, S. (2017) “Seasonal Incidence of Gram Pod Borer, Helicoverpa armigera (Hübner) and Tur Pod Fly, Melanagromyza obtusa (Malloch) on Late Maturing Pigeonpea in Varanasi Region of Indo-Gangetic Plain”, Journal of Experimental Agriculture International, 19(1), (Web Link)

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