RNA interference (RNAi) has been developed as an efficient technology. RNAi insect-resistant transgenic plants expressing double-stranded RNA (dsRNA) that is ingested into insects to silence target genes can affect the viability of these pests or even lead to their death. HaHR3, a molt-regulating transcription factor gene, was previously selected as a target expressed in bacteria and tobacco pl...

Proteinase inhibitors play an important role in plant resistance of insects and pathogens. In this study, we characterized the serine proteinase inhibitor SaPIN2b, which is constitutively expressed in Solanum americanum trichomes and contains two conserved motifs of the proteinase inhibitor II (PIN2) family. The recombinant SaPIN2b (rSaPIN2b), which was expressed in Escherichia coli, was demons...

We investigated colour discrimination and learning in adult males of the nocturnal cotton bollworm moth, Helicoverpa armigera, under a dim light condition. The naive moths preferred blue and discriminated the innately preferred blue from several shades of grey, indicating that the moths have colour vision. After being trained for 2 days to take nectar at a yellow disc, an innately non-preferred...

The P, hobo, Hermes, Minos and mariner transposable elements have been successfully used as gene vectors to achieve genetic transformation of Drosophila melanogaster. The hobo transposable element of D. melanogaster, a member of the hAT family of transposable elements, can also transpose in other dipteran species including the house fly Musca domestica and the Queensland fruit fly, Bactrocera t...

The impact of a tapioca-based artificial diet on the developmental rate, life history parameters, and fertility was examined over five consecutive generations for the cotton bollworm, Helicoverpa armigera Hubner (Lepidoptera: Noctuidae), a highly polyphagous pest of many agricultural crops. The study showed that when fed the tapioca-based artificial diet during larval stage, larval and pupal de...

Hexane, chloroform, ethyl acetate and methanol extracts of Strychnos nux-vomica Linn. (Family: Loganiaceae) and Semecarpus anacardium Linn. (Family: Anacardiaceae) were incorporated in semi-synthetic diet at 0.5, 1.0, 1.5 and 2% concentrations. Screened for antifeedant, larvicidal, pupicidal and adult malformation activities against Helicoverpa armigera (Lepidoptera: Noctuidae). The chloroform ...

Insect fat body is the organ for intermediary metabolism, comparable to vertebrate liver and adipose tissue. Larval fat body is disintegrated to individual fat body cells and then adult fat body is remodeled at the pupal stage. However, little is known about the dissociation mechanism. We find that the moth Helicoverpa armigera cathepsin L (Har-CL) is expressed heavily in the fat body and is re...

Twelve fractions from chloroform extract of Clerodendrum phlomidis and 5,7-dihydroxy4,6-dimethoxy-flavone (pectolinaringenin) were evaluated against Helicoverpa armigera. Maximum antifeedant (89.41%), larvicidal (83.77%) and ovicidal (69.25%) activities were observed in fraction 5. The least LC50 value for antifeedant (178.09 ppm) and larvicidal (198.23 ppm) were observed in fraction 5. No adu...

Recent experimental evidence has shown that learning occurs in the host selection behaviour of Helicoverpa armigera (Hübner), one of the world‘s most important agricultural pests. This paper discusses how the occurrence of learning changes our understanding of the host selection behaviour of this polyphagous moth. Host preferences determined from previous laboratory studies may be vastly differ...