Activity of adult Heliothis armigera (Hb.) (Lepidoptera, Noctuidae) with reference to the flowering of sorghum and maize in Botswana

Abstract

Night-time observations on adults of Heliothis armigera (Hb.), and data from light-trap and hand net catches in irrigated and dryland crops, showed that both sexes flew and fed and females oviposited between 20,00 and 23.00 h. From then until 02.00 h both sexes were inactive, but. from 02.00 to 04.00 h the males flew above the crop in a ' purposeful' manner, while the females were stationary and releasing pheromone. During this period of high male and low female activity, copulation in cages, assembly of males to females in cages and copulating pairs on crop plants were all observed. Inseminated female H. armigera were collected in crops which were at a stage suitable for oviposition, while traps away from crops or near mature crops collected mainly virgin females. It is suggested that susceptible crops attract H. armigera adults and that, once within the crop, inseminated females are ' trapped' by suitable physiological cues from the plants. Identification of such cues could assist in the breeding of crop varieties resistant to H. armigera attack.

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

“…Our description of the nocturnal flight pattern in mature H. armigera is thus similar to that of Topper (1987) who, like us, found that the flight activity of inseminated females peaked slightly later than that of unmated ones. Our results are also consistent with earlier reports by Roome (1975) from Botswana. He noted that the majority of the H. armigera caught in handnets before midnight were females, and he observed females ovipositing and both sexes feeding during this period.…”

“…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.…”

“…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. Concentration of mature moths in the vicinity of our experimental plot would explain their relative preponderance over immatures in the vehicle net catches.…”

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

“…Haggis (1981) deduced that dispersal of adults must be common from her analysis of the spatial and temporal distribution of oviposition of the Sudan. 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).…”

A rearing method forHeliothis armiger confertus, and its use for production of the parasitoidApanteles kazakand two insect viruses

“…The reported tImmg of mating behaviour in H. armiger varies from early evening (Roome 1975) to midnight (Mourikis & Vassilaina-Alexopoulou 1970). Most of the mating observed by Whitlock (1973) occurred at dawn, while Hardwick (1965) observed a maximum between 1030 hand 1130 h. We found that fecundity was low when adults were continuously held at 25°C and 16:8 (LID) photoperiod, and sometime no eggs were laid.…”