Population dynamics, diet and pest status of the grassland melomys (Melomys burtoni) in northern Queensland sugarcane crops

2011 ◽  
Vol 38 (4) ◽  
pp. 330 ◽  
Author(s):  
Brendan C. Dyer ◽  
Anthony R. Clarke ◽  
Susan J. Fuller
Keyword(s):  
Population Dynamics ◽  
Pest Management ◽  
Habitat Type ◽  
Population Monitoring ◽  
Diet Analysis ◽  
Growth Stages ◽  
Pest Status ◽  
Closed Forest ◽  
Crop Development ◽  
Ipm Strategy

Context In far-northern Queensland, Melomys burtoni and M. cervinipes occur within sugarcane crops and adjacent habitats and are potentially damaging to sugarcane. Aims To examine the population dynamics and diet of Melomys spp. within sugarcane crops so that, in conjunction with cane-stalk damage assessments, their pest status could be determined and information provided relevant to the development of sustainable pest-management tools. Methods Eight sites within sugarcane fields, four adjacent to grassland and four adjacent to closed forest, were established around Tully in far-northern Queensland. We examined demographic characteristics of all rodents (the two Melomys spp. and Rattus sordidus) within the crops by capture–release studies. Snap-trapping and dissection studies, along with weed-biomass surveys, were conducted for diet analysis, whereas damaged stalk counts were undertaken to understand the damage process. Fieldwork commenced within a fully developed crop, then continued through the annual harvest period and all subsequent crop growth stages to the next harvest. Sampling was undertaken monthly from February 2005 to April 2006. Key results Melomys cervinipes was rarely caught in sugarcane and should not be regarded as a pest. In contrast, M. burtoni feeds on sugarcane and was responsible for damage to ~6% of stalks. In sites adjacent to closed forest, R. sordidus was found in higher numbers than was M. burtoni in Crop stages 2–4. However, at sites adjacent to grassland, numbers of M. burtoni increased in Crop stage 4, and before crop harvest, M. burtoni was found in higher numbers than was R. sordidus. M. burtoni colonised sugarcane at later stages of crop development than did R. sordidus. Although the level of M. burtoni reproduction was lower than that of R. sordidus, the highest proportion of pregnant M. burtoni individuals occurred during the later stages of crop development, corresponding directly with the highest proportion of juvenile recruitment. Conclusions Of the two Melomys species found in northern Queensland sugarcane crops, only M. burtoni should be regarded as a pest. This rodent breeds and feeds within the crop, primarily after canopy closure. M. burtoni captures were roughly equivalent irrespective of adjacent habitat type, whereas R. sordidus, the traditionally recognised major pest of sugarcane crops, was found in significantly higher numbers in sugarcane adjacent to closed forest. Implications The integrated pest-management (IPM) strategy developed for R. sordidus is centred on the early stages of crop development and includes population monitoring, in-crop weed control, harbourage management and strategic use of permitted rodenticides. The late colonisation and lower breeding potential of M. burtoni mean that the IPM strategy for R. sordidus will not be directly transferable to M. burtoni.

scholarly journals RNAi efficacy is enhanced by chronic dsRNA feeding in pollen beetle

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Jonathan Willow ◽  
Liina Soonvald ◽  
Silva Sulg ◽  
Riina Kaasik ◽  
Ana Isabel Silva ◽  
...  
Keyword(s):  
Rna Interference ◽  
Pest Management ◽  
Oilseed Rape ◽  
Growth Stages ◽  
Short Term ◽  
Pollen Beetle ◽  
Brassicogethes Aeneus ◽  
Crop Growth Stages ◽  
Insecticidal Compounds ◽  
Significant Mortality

AbstractDouble-stranded RNAs (dsRNAs) represent a promising class of biosafe insecticidal compounds. We examined the ability to induce RNA interference (RNAi) in the pollen beetle Brassicogethes aeneus via anther feeding, and compared short-term (3 d) to chronic (17 d) feeding of various concentrations of dsRNA targeting αCOP (dsαCOP). In short-term dsαCOP feeding, only the highest concentration resulted in significant reductions in B. aeneus survival; whereas in chronic dsαCOP feeding, all three concentrations resulted in significant mortality. Chronic dsαCOP feeding also resulted in significantly greater mortality compared to short-term feeding of equivalent dsαCOP concentrations. Our results have implications for the economics and development of dsRNA spray approaches for managing crop pests, in that multiple lower-concentration dsRNA spray treatments across crop growth stages may result in greater pest management efficacy, compared to single treatments using higher dsRNA concentrations. Furthermore, our results highlight the need for research into the development of RNAi cultivars for oilseed rape protection, given the enhanced RNAi efficacy resulting from chronic, compared to short-term, dsRNA feeding in B. aeneus.

scholarly journals Inter-seasonal population dynamics and pest status of Bemisia tabaci (Gennadius) biotype B in an Australian cropping system

2008 ◽  
Vol 99 (4) ◽  
pp. 325-335 ◽  
Author(s):  
R.V. Sequeira ◽  
A. Shields ◽  
A. Moore ◽  
P. De Barro
Keyword(s):  
Population Dynamics ◽  
Bemisia Tabaci ◽  
Cropping System ◽  
Late Summer ◽  
System Component ◽  
Cotton Production ◽  
Pest Status ◽  
Weed Host ◽  
Biotype B ◽  
Seasonal Population

AbstractBemisia tabaci, biotype B, commonly known as the silverleaf whitefly (SLW) is an alien species that invaded Australia in the mid-90s. This paper reports on the invasion ecology of SLW and the factors that are likely to have contributed to the first outbreak of this major pest in an Australian cotton cropping system. Population dynamics of SLW within whitefly-susceptible crop (cotton and cucurbit) and non-crop vegetation (sowthistle, Sonchus spp.) components of the cropping system were investigated over four consecutive growing seasons (September–June) 2001/02–2004/05 in the Emerald Irrigation Area (EIA) of Queensland, Australia. Based on fixed geo-referenced sampling sites, variation in spatial and temporal abundance of SLW within each system component was quantified to provide baseline data for the development of ecologically sustainable pest management strategies. Parasitism of large (3rd and 4th instars) SLW nymphs by native aphelinid wasps was quantified to determine the potential for natural control of SLW populations. Following the initial outbreak in 2001/02, SLW abundance declined and stabilised over the next three seasons. The population dynamics of SLW is characterised by inter-seasonal population cycling between the non-crop (weed) and cotton components of the EIA cropping system. Cotton was the largest sink for and source of SLW during the study period. Over-wintering populations dispersed from weed host plant sources to cotton in spring followed by a reverse dispersal in late summer and autumn to broad-leaved crops and weeds. A basic spatial source-sink analysis showed that SLW adult and nymph densities were higher in cotton fields that were closer to over-wintering weed sources throughout spring than in fields that were further away. Cucurbit fields were not significant sources of SLW and did not appear to contribute significantly to the regional population dynamics of the pest. Substantial parasitism of nymphal stages throughout the study period indicates that native parasitoid species and other natural enemies are important sources of SLW mortality in Australian cotton production systems. Weather conditions and use of broad-spectrum insecticides for pest control are implicated in the initial outbreak and on-going pest status of SLW in the region.

scholarly journals Altitude, habitat type and herbivore damage interact in their effects on plant population dynamics

PLoS ONE ◽  
2018 ◽  
Vol 13 (12) ◽  
pp. e0209149 ◽  
Author(s):  
Tomáš Dostálek ◽  
Maan Bahadur Rokaya ◽  
Zuzana Münzbergová
Keyword(s):  
Population Dynamics ◽  
Habitat Type ◽  
Plant Population ◽  
Plant Population Dynamics ◽  
Herbivore Damage

scholarly journals MEDITERATRI project - assessing the trophic ecology of predatory arthropods in Mediterranean agriculture via DNA metabarcoding diet analyses

2019 ◽  
Vol 2 ◽  
Author(s):  
Lucija Šerić Jelaska ◽  
Barbara Anđelić ◽  
Mišel Jelić ◽  
Tomislav Kos
Keyword(s):  
Pest Management ◽  
Trophic Ecology ◽  
Arable Land ◽  
Carabid Beetles ◽  
Diet Analysis ◽  
Gut Contents ◽  
Dna Metabarcoding ◽  
Potential Benefits ◽  
Diet Analyses ◽  
Predatory Arthropods

A type of management and the use of pesticides in arable land may negatively affect a range of soil biota and thus their food webs important for ecosystem functioning. By analysing trophic interactions we could reveal the extent of potential benefits that certain organisms can provide in biocontrol and maintaining healthy ecosystems. To evaluate the role of predatory arthropods within olive orchards and vineyards under Integrated Pest Management (IPM) and Ecological Pest Management (EPM) we collected carabid beetles together with other dominant predatory arthropods in the field (e.g. ladybugs, antlions, spiders, centipedes) and subdued the individuals to molecular gut content analyses using NGS. DNA metabarcoding diet analysis approach allowed detecting a wide variety of taxa from gut contents of the predators. In addition, using ICP-MS and LC-MS/MS we quantified Cu, pesticides and its residues in soil and animals representing different trophic guilds. Since concentrations of some toxic compounds detected in carabids body were negatively correlated with those in the soil, we aim to identify a potential vector for possible transfer of toxicants to general predators via predation. The results contribute to the risk assessment of proliferation of detected chemical compounds including copper in the ecosystem and to the knowledge on the overall field sustainability of predatory invertebrates to maximize their role in pest control. The study was conducted under the project activity of HRZZ – Mediteratri.

scholarly journals Population Structure of Harvested Red Foxes (Vulpes vulpes) and Coyotes (Canis latrans) on Prince Edward Island, Canada

2013 ◽  
Vol 126 (4) ◽  
pp. 288 ◽  
Author(s):  
Wendela Wapenaar ◽  
Fiep De Bie ◽  
David Johnston ◽  
Ryan M. O'Handley ◽  
Herman W. Barkema
Keyword(s):  
Population Dynamics ◽  
Wildlife Management ◽  
Urban Areas ◽  
Vulpes Vulpes ◽  
Prince Edward Island ◽  
Canis Latrans ◽  
Habitat Type ◽  
Red Foxes ◽  
Wild Canids ◽  
Agricultural Areas

An understanding of the population dynamics and habitat of wild Red Foxes (Vulpes vulpes) and Coyotes (Canis latrans) is a prerequisite to wildlife management. This information is also important in assessing the risk these wild canids pose to the public and domestic animals. On Prince Edward Island, information on age, sex, reproductive activity, and habitat use of 271 Red Foxes and 201 Coyotes was collected in the hunting and trapping season of 2004–2005. The estimated age of Red Foxes and Coyotes ranged from 0.5 to 13.5 years. A large proportion of harvested Red Foxes and Coyotes (58% and 48%, respectively) consisted of juveniles. The sex ratio was not significantly different from 1:1 for either species. Average litter size was 5.0 and 5.2 for Red Foxes and Coyotes, respectively. Number of placental scars ranged from 0 to 7 in Red Foxes and from 0 to 11 in Coyotes. Agricultural areas were the main habitat type (52%) of harvested Red Foxes. For harvested Coyotes, forest was the main habitat (44%), followed closely by agricultural areas (43%). Urban areas were a significant part (13%) of the habitat of Red Foxes. These data can be used to monitor population dynamics over time, provide information for wildlife management, and provide information on potential risk areas for disease transmission by wild canids.

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