The incidence of Heliothis armigera (Hübner) and H. punctigera Wallengren (Lepidoptera: Noctuidae) on cotton and other host-plants in the Namoi Valley of New South Wales

Abstract

Four years of light-trap and crop survey data from the Namoi Valley of New South Wales are presented for Heliothis armigera (Hb.) and H. punctigera Wllgr. These suggest there are four generations a year. The associated seasonal sequence of major host-plants supporting successive generations, appeared to be: H. armigera-wheat; pre-flowering cotton; flowering cotton and sorghum; sorghum, flowering cotton and sunflowers; and H. punctigera-lucerne, linseed and medics; pre-flowering cotton; flowering cotton, sunflowers and soyabeans; lucerne and flowering cotton. On host-plants common to both species, a change in dominance from H. punctigera to H. armigera occurred as each summer progressed. Suggested causes are: seasonal changes in the availability of host-plants, favouring H. armigera over H. punctigera; insecticide resistance in H. armigera; and the competitive superiority of H. armigera. Large numbers of H. armigera in cotton appeared to be related to: warm springs, which favoured moth emergence during the period of wheat anthesis; the incomplete control of infestations within cotton itself, leading to the development of resident populations; and the influx of moths from other host-plants, especially sorghum, during the latter half of the season.

Nocturnal observations on the emergence and flight behaviour of Helicoverpa armigera (Lepidoptera: Noctuidae) in the post-rainy season in central India

“…Once mated, flight propensity drops dramatically (Armes & Cooter, 1991) and this precludes the likelihood of long distance movement. This is consistent with the observations of Roome (1975), Wardhaugh et al (1980) and Topper (1987) who found that H. armigera populations appear to be sedentary in the presence of flowering host plants. In addition to environmental effects, there may also be a genetic factor which influences the migratory potential and pre-reproductive period between populations (Colvin, 1990).…”

“…There was strong evidence from the marking experiment (King et al, 1990) that this was, in fact, occurring. Other authors have found evidence for such a 'capture' effect (Parsons, 1940;Roome, 1975;Wardhaugh et al, 1980). Roome (1975), for example, noted that more mated female H. armigera were taken in light traps placed in flowering sorghum and tasselling maize than in traps placed in maturing crops.…”

Genetic variation inHeliothisin Australia: species identification and gene flow in the two pest species H. armigera (Hübner) and H.punctigeraWallengren (Lepidoptera: Noctuidae)

“…comm.). At present, there is no evidence of long range seasonal migrations in H. armigera in Australia such as are observed in H. punctigera and other insects (Wardhaugh et al, 1980;Wilson, 1983;Drake & R. A. Farrow, pers. comm.…”

“…On the other hand, Roome (1975) observed that populations of H. armigera from southern Africa were sedentary in the presence of flowering host-plants. In Australia, while H. punctigera is migratory (Drake et al, 1981), H. armigera is considered to be more sedentary (Wardhaugh et al, 1980). Certainly, within a locality in a growing season, H. armigera populations appear to be sedentary in cotton crops and other flowering hosts whereas H. punctigera is highly mobile (Morton et al, 1981;Wardhaugh, pers.…”

“…In the two sympatric species of Heliothis, differences in the biotic factors are likely to be very important. From observations of Heliothis in the cotton crops in northern New South Wales (Wardhaugh et al, 1980), Wardhaugh (pers. comm.…”