A Record of Beneficial Arthropods and Insect Diseases in Southeast Queensland Cotton

Spiders are among the most abundant predators recorded in grain crops in Australia. They are voracious predators, and combined with their high abundance, may play an important role in the reduction of pest populations. The significance of spider assemblages as biological control agents of key pests such as Helicoverpa spp. in Australian agroecosystems is largely unknown. A thorough inventory was made of the spider fauna inhabiting unsprayed soybean fields at Gatton, south-east Queensland. Onehundred-and-two morphospecies from 28 families were collected using vacuum sampling and pitfall traps across two summer seasons . No-choice feeding tests in the laboratory, using eggs and larvae of Helicoverpa armigera (Hübner) as prey, were used to ascertain the predatory potential of each spider group. The field-collected spider assemblage ate on average 2.4 ( ± 0.7 standard error) to 5.0 ( ± 0.8) eggs per 24 h per spider (10-25% of those available), depending on level of starvation. Clubionidae were the only spiders to readily consume eggs in the laboratory (mean of 18.4 ± 1.5 eggs per starved spider and 8.2 ± 3.9 per non-starved spider after 24 h). Starved spiders consumed 9.4 ( ± 0.1) first-instar larvae per 24 h per spider (90% of those available). This information was combined with field observations and literature from Australian and overseas studies to assess the potential of spider groups as predators of Helicoverpa spp. Lycosidae, Clubionidae, Oxyopidae, Salticidae and Thomisidae have the capacity to contribute to control of Helicoverpa spp.

Section: Discussionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Spider fauna of soybean crops in south‐east Queensland and their potential as predators of Helicoverpa spp. (Lepidoptera: Noctuidae)

Pearce

Hebron

Raven

et al. 2004

“…Leis conformis (Boisduval) and Coelophora inaequulis (Mulsant), for example, are common in cotton in S.E. Queensland (Bishop and Blood 1977) but absent from cotton in the Namoi Valley. Table 3 gives an indication of the rates at which the predators consume Heliothis spp.…”

Section: S P ; Diomus Notescens Campylomma Livida Oxycarenus Luctumentioning

confidence: 99%

PARASITES and PREDATORS OF HELIOTHIS SPP. (LEPIDOPTERA: NOCTU1DAE) IN COTTON IN THE NAMOI VALLEY, NEW SOUTH WALES

Room

1980

Four species of Diptera and 12 species of Hymenoptera were recorded as parasites and evidence was obtained that at least 19 species of insect, five species of spider and house mice were predators of Heliothis spp. A further 12 species of predaceous insect and three species of spider were also common in unsprayed cotton. Data are presented on consumption of Heliothis eggs and small larvae by various insects and spiders in petri dishes.

“…Egg parasitoid records associated with cotton crops across Australia are summarised in Figure 1. Twine (1973), Bishop and Blood (1977), Room (1979), Scholz (1991), Scholz and Murray (1995) and Johnson et al . (2000) report several species of Trichogramma attacking lepidopterous pests in eastern Australian cotton‐growing regions such as the Namoi Valley (29°28′S, 149°51′E) in New South Wales (NSW) and the Darling Downs (27°33′S, 152°17′E) in Queensland.…”

Section: Introductionmentioning

confidence: 99%

Using Trichogramma Westwood (Hymenoptera: Trichogrammatidae) for insect pest biological control in cotton crops: an Australian perspective

Davies

Carr

Scholz³

et al. 2011

Trichogramma Westwood egg parasitoids alone generally fail to suppress heliothine pests when released in established cotton-growing regions. Factors hindering their success include indiscriminate use of detrimental insecticides, compensation for minimal pest larval hatch due to their activity via reduced larval cannibalism or mortality in general, singly laid heliothine eggs avoiding detection and asynchronous development benefiting host over parasitoid. Yet, despite these limitations, relatively large Trichogramma pretiosum Riley populations pervade and effectively suppress Helicoverpa (Hardwick) pests in Australian Bt (Bacillus thuringiensis Berliner)-transgenic cotton, Gossypium hirsutum L., crops, especially in the Ord River Irrigation Area (ORIA) of tropical northern Australia, where their impact on the potentially resistant pest species, Helicoverpa armigera (Hübner), is considered integral to the local insecticide resistance management (IRM) strategy for continued, sustainable Bt-transgenic cotton production. When devoid of conventional insecticides, relatively warm and stable conditions of the early dry season in 'winter' grown ORIA Bt-transgenic cotton crops are conducive to Trichogramma proliferation and biological control appears effective. Further, there is considerable scope to improve Trichogramma's biological control potential, in both the ORIA and established cotton-growing regions, via habitat manipulation. It is proposed that Trichogramma may prove equally effective in developing agricultural regions of monsoonal northern Australia, and that environmental constraints on Trichogramma survival, and those of other natural enemies, require due consideration prior to their successful application in biological control programs.