Influence of Cotton Microhabitat on Temperature and Survival of<i>Trichogramma</i>(Hymenoptera: Trichogrammatidae) within Cardboard Capsules

Suh, Charles P.-C.; Orr, David B.; Duyn, John W. Van; Borchert, Daniel M.

doi:10.1603/0046-225x-31.2.361

Cited by 8 publications

(4 citation statements)

References 8 publications

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“…in cotton was located within the plant canopy sheltered from ambient winds and high temperatures. Before full canopy closure, the middle section of cotton plants provides a relatively cool humid environment for Trichogramma activity (Suh et al , 2002). This effect disappears late in the season after canopy closure.…”

Section: Discussionmentioning

confidence: 99%

Spatio-temporal variation in Helicoverpa egg parasitism by Trichogramma in a tropical Bt-transgenic cotton landscape

Davies

Pufke²,

Zalucki

2011

Agricultural and Forest Entomology

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1 Understanding the spatio-temporal dynamics of insects in agroecosystems is crucial when developing effective management strategies that emphasize the biological control of pests. 2 Wild populations of Trichogramma Westwood egg parasitoids are utilized for the biological suppression of the potentially resistant pest species Helicoverpa armigera (Hübner) in Bt-transgenic cotton Gossypium hirsutum L. crops in the Ord River Irrigation Area (ORIA), Western Australia, Australia. 3 Extensive, spatially-stratified sampling during a season of relatively high Trichogramma abundance found that spatial patterns of pest egg parasitism in the ORIA tend toward heterogeneity, and do not necessarily coincide with host spatiotemporal dynamics. Both patterns of host egg density and mean rates of parasitism are not good indicators of parasitoid spatio-temporal dynamics in ORIA cotton crops. 4 Parasitism rates can be significantly higher within the middle strata of the cotton plant canopy before complete canopy closure, despite a similar number of host eggs being available elsewhere in the plant. 5 Spatial variation in egg parasitism by Trichogramma in Bt-transgenic cotton is evident at the between-field, within-field and within-plant scale, and is not solely driven by host spatial dynamics. These factors should be considered when estimating Trichogramma impact on pest species during biological control and spatio-temporal studies of host-parasitoid interactions in general.

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Section: Discussionmentioning

confidence: 99%

Spatio-temporal variation in Helicoverpa egg parasitism by Trichogramma in a tropical Bt-transgenic cotton landscape

Davies

Pufke²,

Zalucki

2011

Agricultural and Forest Entomology

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“…Furthermore, laboratory bioassays are generally conducted in an environment that is benign to the biocontrol agent, with the goal of achieving low levels of mortality in the control treatment. In nature, however, even an agroecosystem that is free of pesticide residues may still be relatively hostile to a biological control agent if it is devoid of key food resources (reviewed in Jervis et al 1993;Heimpel et al 1997), occupied by higher-order predators (Rosenheim 1998), or presents harsh abiotic conditions (Suh et al 2002). These factors could, in theory, reduce survivorship in the absence of pesticide residues to levels that approach those seen in the presence of the pesticide residue.…”

Section: Introductionmentioning

confidence: 99%

The impact of sulfur on the reproductive success of Anagrus spp. parasitoids in the field

2007

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Pesticides targeted at pest species have often been demonstrated to have strong adverse effects on the survival of biological control agents in short-term laboratory bioassays; however, studies examining the influence of pesticides on the actual reproductive success of biological control agents in the field are rare. Because natural enemy reproduction is often directly tied to biological control success, effects of pesticides on reproduction are of central importance. Here we use a new technique to examine the influence of sulfur, a fungicide widely used in grape production, on the reproductive success of Anagrus erythroneurae (Hymenoptera: Mymaridae) and Anagrus daanei (Hymenoptera: Mymaridae), egg parasitoids of the grape leafhopper, Erythroneura elegantula (Homoptera: Cicadellidae). Sulfur has previously been shown to be highly toxic to Anagrus spp. in short-term laboratory and field bioassays, creating the expectation that sulfur should also reduce Anagrus reproductive success in the field. Surprisingly, in two studies, the first comparing the oviposition success of Anagrus collected live in paired sulfur-treated versus untreated vineyards and the second comparing the lifetime reproductive success of Anagrus collected at the end of their lives in unpaired sulfur-treated versus untreated vineyards, we found no effect of sulfur on parasitoid reproductive success. In this system, traditional short-term assays of laboratory toxicity do not appear to predict effects on parasitoid reproductive success, suggesting that demographic approaches to assessing the disruptive effects of pesticides may have an important role in designing IPM programs.

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“…Asynchronous development alone does not explain, in terms of density dependence, cases of Trichogramma inoculation that achieve high parasitism levels concurrent with high pest abundance that ultimately result in limited control and unacceptable crop damage (Twine andLloyd 1982, Losey et al 1995). Adult Trichogramma survival, reproductive potential and searching ability, and the development of immatures can be limited by environmental constraints such as chemical applications (Varma and Singh 1987;Navarajan-Paul and Agarwal 1989;Campbell et al 1991;Scholz 1994;Consoli et al 1998;Hassan et al 1998;Scholz et al 1998;Brunner et al 2001;Consoli et al 2001;Takada et al 2001;Vieira et al 2001) and unsuitable climatic conditions (Gross 1988, Grille and Basso 1995, Orr et al 1997, Suh et al 2002 or habitat characteristics (Romeis et al 1999a,b), despite the presence of large numbers of hosts. Host abundance itself may not be the sole driving force behind the dynamics of a natural enemy population, but rather a reßection of the interaction between the attributes of individuals within that population and the characteristics of the environment (Walter and Hengeveld 2000).…”

Section: Fieldmentioning

confidence: 99%

<I>Trichogramma</I> (Hymenoptera: Trichogrammatidae) Ecology in a Tropical Bt Transgenic Cotton Cropping System: Sampling to Improve Seasonal Pest Impact Estimates in the Ord River Irrigation Area, Australia

Davies¹,

Pufke²,

Zalucki³

2009

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Trichogramma Westwood (Hymenoptera: Trichogrammatidae) cause high mortality rates in the potentially resistant pest species, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), and are considered integral to the resistance management plan for Bacillus thuringiensis transgenic cotton, Gossypium hirsutum L., production in the Ord River Irrigation Area (ORIA), Western Australia. Measured as percentage of parasitism, Trichogramma activity seems highly variable over time; yet, it contributes significantly to pest suppression at peak insect pest density. Environmental constraints on Trichogramma survival, especially insecticide applications, may limit their effectiveness. The decision to initiate insecticide applications in ORIA cotton crops is best delayed unless absolutely necessary to avoid disruption of Trichogramma impact on pests. Trichogramma disperse into young crops and display high intrinsic rates of increase effectively stifling Helicoverpa (Hardwick) population increase after initial egg lay during high-density years in the ORIA, and evidence suggests a possible preference for H. armigera host eggs.

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Influence of Cotton Microhabitat on Temperature and Survival ofTrichogramma(Hymenoptera: Trichogrammatidae) within Cardboard Capsules

Cited by 8 publications

References 8 publications

Spatio-temporal variation in Helicoverpa egg parasitism by Trichogramma in a tropical Bt-transgenic cotton landscape

Spatio-temporal variation in Helicoverpa egg parasitism by Trichogramma in a tropical Bt-transgenic cotton landscape

The impact of sulfur on the reproductive success of Anagrus spp. parasitoids in the field

<I>Trichogramma</I> (Hymenoptera: Trichogrammatidae) Ecology in a Tropical Bt Transgenic Cotton Cropping System: Sampling to Improve Seasonal Pest Impact Estimates in the Ord River Irrigation Area, Australia

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