ADAPTATION OF THE CORN EARWORM SINGLE NUCLEOCAPCIDE NUCLEOPOLYHEDROVIRUS (HELICOVERPA ZEA SNPV) FOR THE CONTROL OF THE COTTON BOLLWORM (HELICOVERPA ARMIGERA) POPULATION

Helicoverpa zea (Boddie, 1850) (Hz) single nucleocapcide nucleopolyhedrovirus (SNPV) was adapted to the cotton bollworm (Helicoverpa armigera, (Hübner, 1805) (Ha)) by five blind passages on larvae. The full genomic sequence of the resulting strain HS-18 has been determined (GenBank acc. №: KJ004000.1). Biological activity of the HS-18 strain is higher than the activity of all other Russian strains of NPV, as far as cotton bollworm strain HearSNPV-G4. HS-18-infected caterpillars at the 3-rd and 4-th ages died much faster than those infected with HearSNPV-G4 strain. A major difference of HS-18 genome is an 18 bp repeat in the RING-finger ORF that confirms high variability of this region. Three other insertions and seven base substitutions were observed earlier, while six base substitutions are new. Mutations are located at ORF42, lef-9, ORF58, VP39, PIF-4, P48, SOD, ORF111, ORF129 and ORF138 genes. Among all nucleotide mutation only one is synonymous. Thus we suppose the selective pressure to the virus. The resulting strain HS-18 is recommended as a biopesticide for controlling the number of cotton bollworm in cotton fields.

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Competition of the cotton bollworm (Helicoverpa armigera), corn earworm (Helicoverpa zea) and fall armyworm (Spodoptera frugiperda) on non-Bt corn

10.1603/ice.2016.114451 ◽

2016 ◽

Author(s):

José P. G. F. Silva

Keyword(s):

Helicoverpa Armigera ◽

Spodoptera Frugiperda ◽

Helicoverpa Zea ◽

Fall Armyworm ◽

Corn Earworm ◽

Cotton Bollworm ◽

Bt Corn ◽

Helicoverpa Armígera

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Comparative Toxicity of Helicoverpa armigera and Helicoverpa zea (Lepidoptera: Noctuidae) to Selected Insecticides

Insects ◽

10.3390/insects11070431 ◽

2020 ◽

Vol 11 (7) ◽

pp. 431 ◽

Cited By ~ 1

Author(s):

Fernando R. da Silva ◽

Dario Trujillo ◽

Oderlei Bernardi ◽

Jose Carlos Verle Rodrigues ◽

Woodward D. Bailey ◽

...

Keyword(s):

Puerto Rico ◽

Acute Toxicity ◽

Insecticide Resistance ◽

Helicoverpa Armigera ◽

Helicoverpa Zea ◽

Corn Earworm ◽

Median Lethal Concentration ◽

Helicoverpa Armígera ◽

Old World Bollworm ◽

Lepidoptera Noctuidae

Until recently, the Old World bollworm (OWB) Helicoverpa armigera (Hübner) and the corn earworm Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) were geographically isolated. Both species are major pests of agricultural commodities that are known to develop insecticide resistance, and they now coexist in areas where H. armigera invaded the Americas. This is the first study to compare the susceptibility of the two species to conventional insecticides. The susceptibility of third instar H. armigera and H. zea larvae to indoxacarb, methomyl, spinetoram, and spinosad was determined using a diet-overlay bioassay in a quarantine laboratory in Puerto Rico. Mortality was assessed at 48 h after exposure for up to eight concentrations per insecticide. Spinetoram exhibited the highest acute toxicity against H. armigera, with a median lethal concentration (LC50) of 0.11 µg a.i./cm2, followed by indoxacarb and spinosad (0.17 µg a.i./cm2 for both) and methomyl (0.32 µg a.i./cm2). Spinetoram was also the most toxic to H. zea (LC50 of 0.08 µg a.i./cm2), followed by spinosad (0.17 µg a.i./cm2) and methomyl (0.18 µg a.i./cm2). Indoxacarb was the least toxic to H. zea, with an LC50 of 0.21 µg a.i./cm2. These findings could serve as a comparative reference for monitoring the susceptibility of H. armigera and H. zea to indoxacarb, methomyl, spinetoram, and spinosad in Puerto Rico, and may facilitate the detection of field-selected resistance for these two species and their potential hybrids in areas recently invaded by H. armigera.

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