Trichogramma pretiosum is a key natural enemy of heliothis (Helicoverpa spp. ) on the Darling Downs. The data presented here describe some of the biological parameters of T. pretiosum, and may be useful in future population models that predict the impact of this valuable egg parasitoid on heliothis. Here we report on the lifespan, parasitism levels and progeny production of T. pretiosum reared on Helilicoverpa armigera in the laboratory.

There is increasing interest in utilising Trichogramma egg parasitoids against helothis(Helicoverpa spp. ) in cotton, and crops that may act as sources of parasitoids for cotton -such as sorghum. Very little has been published on the effect of different release rates ofwasps against helothis.Here we report on field trials evaluating different release rates of Trichogrommo pretiosumagainst Hencoverpa armigera in the sorghum and cotton at Evanslea on the easternDarling Downs.

There appears to have been a change in the importance of pests presenting cotton over the last decade. This has involved former secondary pests, such as aphids, A. gossypii, minds, Creontiodes spp. , green vegetable bugs, Nezara viridula (L. ), and whitefly, Bemisia tabaci (Gennadius), having attained greater prominence (Wilson 2002); relative pest pressures for these species are higher in B.t. than non-B.t. cotton (Doyle et al. 2002). The change in pest spectrum is likely to be a consequence of widespread adoption of IPM programmes (Wilson 2002). These sucking pests are a problem in IPM programmes, as broad-spectrum insecticide treatment is very disruptive to the beneficial arthropod fauna (particularly early-season applications), few narrow-spectrum insecticides are available, densities may flare following treatment with broad-spectrum insecticides (Wilson et al. 1998, 1999; SIosser et al. 2000), and little is known about the impact of their natural enemies (Wilson et al. 1998; Wilson 2002). As a consequence there is a requirement to determine the damage potential of a &#39new&#39 pest complex that contains several key pest species, not just a single species such as heIiothis, and for refinement of IPM programmes to better manage these pests. We conducted a season-long field trial better understand the impact of beneficial and pest arthropods, and to refine IPM programmes to better manage these &#39secondary&#39 pests. Treatments were designed to selectively manipulate beneficial and pest arthropod densities to enable examination of predator-prey relationships, and measurement of the relative impact of different beneficial and pest arthropod groups. We recognised two broad prey categories based on the mouthparts of the economically damaging life-stage; &#39chewing&#39 and &#39sucking&#39 pests. The chewing pest group predominantly comprised heliothis, the traditional major pest of cotton, while the sucking group comprised species formerly considered secondary pests, such as aphids, green mirids, green vegetable bugs and whitefly. These pest groups were managed alone or in combination using narrow-spectrum insecticides to supplement &#39natural&#39 mortality factors, although the treatments are &#39imperfect&#39 as the insecticides also reduced the abundance of beneficial arthropods.

Many beneficial arthropods exhibit life-history omnivory (Polis & Strong 1996), in that they include honeydew, floral nectar, extra-floral nectar and/or pollen in their immature or adult diet (Hagen 1986; Coll & Guershon 2002). Access to these resources may increase the abundance and rate of parasitism and predation by these arthropods. Carbohydrate and/or protein mixtures, such as Amino-Feed UV' Envirofeast' and Pred-Feed' can be applied to cotton crops to act as artificial supplemental food sources for beneficial arthropods. The rationale is to improve the synchrony of beneficial and prey or host populations in time and space (Hagen 1986) by one or more of the following: increased immigration and lowered emigration rates of beneficial arthropods (Evans & Swallow 1993; Evans & Richards 1997; Mensah 1997); consumption of the supplement by beneficial arthropods, leading to higher survival and/or reproduction (MCEwen et al 1996); higher parasitism or predation rates (Mensah & Singleton 1999, but see McEwen et al. 1996); and reduced number of eggs laid by pest arthropods (Mensah 1996). Field testing of artificial food supplements in cotton has focussed on targeting a few pest species (mostly heliothis), usually with multiple treatments (range I to 13) applied at 7 to 14 day intervals up until flowering or early boll filling growth stages (i. e. , until January or early February) (Mensah 1997, 2002a; Mensah & Singleton 2002). The early to middle part of the growing season was often targeted because pest densities were typically low to moderate (which leads to reduced application of disruptive insecticides), beneficial arthropods were perceived to effectively suppress these pest densities (Murray & Mensah 1996), and beneficial arthropod densities were thought to decline from January onwards, regardless of possible food supplement treatments (Mensah 2002a, b; but see Scholz et al. 2002). There is scope to extend the 'application window' of supplements to include a wider range of pest species over the entire season. This opportunity is the consequence of improved development and increased adoption of IPM programmes for cotton (Wilson 2002). It is imperative that proposed changes to the nature of artificial food supplement programmes are economically feasible. In this study we assessed the effectiveness of applying multiple treatments of an artificial food supplement (Amino-Feed UV') during the growing season to enhance beneficial arthropod densities. We measured beneficial and pest arthropod abundance, mortality rates of sentinel heliothis egos, fruit counts, crop yield and fibre quality.

Determining the impact of species considered potentially important natural enemies of crop pests is crucial for making robust management decisions as part of an IPM programme (Ives 1980; Johnson et al. 2000; Wilson 2002). Determination of prey species present in the diet of predaceous arthropods is an initial step in assessing their potential impact as biological control agents. Pacific damsel bugs are classified as 'generalist' predators, as they are known to feed on a large number of species from various taxonomic groups; 19 known arthropod species from 11 families in four orders are presently recognised as prey; including cotton aphids, Aphis gossypii, Glover, Heliothis, Helicoverpa armigera (Hubner), and mirids, Creontiades spp. Despite this, distinct biases are likely to exist for particular prey species. Measurement of the feeding rates of key predaceous arthropods on selected prey species, and elucidating the factors that affect this, is the next step in assessing their potential impact. Unfortunately laboratory tests tend to overestimate feeding rates by using artificially high prey densities; such results would not be applicable to field conditions without further testing. For example, the number of heIiothis eggs consumed by female Pacific damsel bugs, Nabis kinbergii Reuter, in 24 hours was reduced by 77, 74 and 92 % when caged on a single small, medium or large cotton plant, respectively, compared to a Petri dish (51.3 eggs per bug per day) (Johnson 1999). This suggests the ability of predators to find and consume prey is substantially reduced as the crop canopy expands and becomes more complex. A good approach to quantify the impact of predation by Pacific damsel bugs on arthropod pest densities is to combine a range of techniques, such as direct observation and cage inclusion studies. In this paper, we use glasshouse and field observations and glasshouse inclusion cage studies to determine the natural diet of the Pacific damsel bug, their feeding rates, and the influence of prey species, prey life stage and prey and predator density on these rates.

With increasing adoption of IPM practices in cotton, green vegetable bugs (GVB) have emerged as important sucking pests causing considerable damage to growing bons (Khan and Bauer 2001, 2002). GVB damage includes black spots at feeding sites on the bon, warty growth inside the bon wall and brown coloured lint. GVB is a polyphagous insect and feeds on a wide variety of field crops including cotton, coin, sunflower, a range of legumes and pulses including adzuki, mung, navy and soybeans, Iucerne, pigeon pea, fruit crops, vegetables and variety of weed hosts including wild turnip, noogoora burr, marshmallow and castor oil. Some of these hosts are more attractive to GVB than others.

Silverleaf whitefly (SLW) is an introduced pest to Australia, having first been discovered in the early 1990's. It was not until the 2001-02 season that a serious outbreak occurred on the Central Highlands and to a lessor extent the Dawson Valley, impacting on a variety of crops including cotton, peanuts, melons, sunflower, soybeans and nursery plants. It also diminished air quality (from clouds of insects) thereby affecting quality of life of townsfolk and destroyed numerous varieties of garden plants. The outbreak occurred partly due to the inability of local cropping industries to control the pest in a number of situations, especially cotton. To address this issue, the Central Queensland cotton industry and QDPl&F invested much time and effort to rapidly develop a management strategy for the pest.

Central Queensland currently enjoys an ascochyta blight free status, however the use of chickpeas as a winter trap crop has created a potential risk for the introduction of the disease. To address this problem we have evaluated alternative winter active legumes over the last three seasons for their suitability to be substituted for chickpeas as a spring trap crop in central Queensland. Field peas have been identified as being highly attractive to egg laying Helicovera spp. moths during each season and it is now our recommendation that growers in CQ use field peas (cvs Alma or Glenroy) for their spring trap crop.

The Assassin Bug, Pristhesancus plagipennis is a natural enemy with considerable promise for controlling HeIiothis (Helicoverpa spp.) and mirids in cotton. However, this promise is offset by several challenges that currently prevent its use as a commercial biological control agent. This paper will place the results of our research into context and speculate on the future of this predator and its place within cotton IPM programs

Uptakes of phosphorus, potassium, calcium, magnesium, sulphur, zinc, manganese, iron and copper were measured in an experiment evaluating nutrition of cotton in a newly developed field. Uptake amounts of each nutrient were similar to reported values, although the pattern of uptake varied in some cases, possibly as a result of different temperature patterns experienced by cotton in a dry season winter production system. This data will assist with developing fertiliser programs