Records of virus diseases in insects in Queensland

Thirteen virus diseases of insects found in Queensland since 1965 are listed in a table under the names of the 17 species of Lepidoptera in which they were found. The food-plants of the hosts and the dates and places where the infected larvae were found are given

A nuclear-polyhedrosis virus from Heliothis punctigera Wallengren (Lepidoptera: Noctuidae)

A nuclear polyhedrosis virus isolated from larvae of Heliothis punctigera Wllgr. on lucerne in Queensland in 1967-68 is described on the basis of the morphology and size of the polyhedra and virions, pathology, and the incubation period in laboratory infections. The virus did not infect larvae of six other species of Lepidoptera (including the beneficial Cactoblastis cactorum (Berg)) and could be distinguished serologically from viruses from four species. It could not be distinguished from a virus from H. armigera (Hb.), and the viruses from H. punctigera and H. armigera showed reciprocal cross- infectivity

A modified complement fixation test for bovine contagious pleuropneumonia for large scale laboratory use

Rapid testing of large numbers of cattle serum samples for complement fixing antibodies for bovine contagious pleuropneumonia was achieved by initially testing at a 1 in 10 dilution only. This screen test w.as carried out in a known order and only those sera showing fixation were identified, recorded and retested at dilutions of from 1 in 10 to 1 in 160

A virus disease of Pieris rapae (L.) in Queensland

The incidence of a virus with particles of similar measurements to those of the P. rapae granulosis virus Bergoldia virulentun is discussed

Interactions between Nuclear Polyhedrosis Virus and Three Larval Parasitoids of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)

Interactions between a Helicoverpa nuclear polyhedrosis virus (NPV) and three larval parasitoids of H. armigera were recorded in laboratory studies. the parasitoids Microplitis demolitor, Cotesia kazak and Hyposoter didymator required a time advantage of at least 3 d at 25°C before the host was exposed to NPV to ensure successful completion of development. Helicoverpa larvae parasitised by C. kazak died from NPV after the parasitoids emerged from the host, and thus could provide a source of virus inoculum for secondary spread of the disease. On the other hand, as the interval between parasitisation and host exposure to NPV increased, the proportion of hosts parasitised by M. demolitor which died from NPV after emergence of the parasitoid decreased. It was also shown that as the time interval between host parasitisation by M. demolitor and exposure to virus increased, higher virus doses were required to kill parasitised hosts than were required for nonparasitised hosts of the same age

Microbial biopesticides and integrated pest management

Increasing environmental, regulatory and market pressures, along with increasing pest resistance, are dictating a progressive move away from chemicals for insect pest control. Insect pathogens (viruses, bacteria, fungi and nematodes), produced artificially and formulated into microbial biopesticides, can provide part of the answer, both as alternatives to chemicals and as components of resistance management strategies. White the large markets, particularly for Bacillus thuringiensis, are dominated by large multinationals, there is considerable scope for local producers to target regional and niche markets. The development of microbial pesticides requires research into production, formulation, application and adoption issues for each product. The Cooperative Research Centre (CRC) for Tropical Pest Management has research interests in initial development, application strategies and adoption of microbial biopesticides in integrated pest management programs. Collaborative programs involving potential producers with expertise in medium and large scale production, and users are essential for the long-term success of biopesticides. The CRC concept is well suited to such collaborative research

Host recognition by a polyphagous lepidopteran (Helicoverpa armigera): primary host plants, host produced volatiles and neurosensory stimulation

An important question in the host-finding behaviour of a polyphagous insect is whether the insect recognizes a suite or template of chemicals that are common to many plants? To answer this question, headspace volatiles of a subset of commonly used host plants (pigeon pea, tobacco, cotton and bean) and nonhost plants (lantana and oleander) of Helicoverpa armigera Hubner (Lepidoptera: Noctuidae) are screened by gas chromatography (GC) linked to a mated female H. armigera electroantennograph (EAG). In the present study, pigeon pea is postulated to be a primary host plant of the insect, for comparison of the EAG responses across the test plants. EAG responses for pigeon pea volatiles are also compared between females of different physiological status (virgin and mated females) and the sexes. Eight electrophysiologically active compounds in pigeon pea headspace are identified in relatively high concentrations using GC linked to mass spectrometry (GC-MS). These comprised three green leaf volatiles [(2E)-hexenal, (3Z)-hexenylacetate and (3Z)-hexenyl-2-methylbutyrate] and five monoterpenes (alpha-pinene,beta-myrcene, limonene, E-beta-ocimene and linalool). Other tested host plants have a smaller subset of these electrophysiologically active compounds and even the nonhost plants contain some of these compounds, all at relatively lower concentrations than pigeon pea. The physiological status or sex of the moths has no effect on the responses for these identified compounds. The present study demonstrates how some host plants can be primary targets for moths that are searching for hosts whereas the other host plants are incidental or secondary targets