scholarly journals The impact of food on the growth of clones of Lecane inermis, a potential bulking control agent

2017 ◽  
Vol 43 (1) ◽  
Author(s):  
EWA KOWALSKA ◽  
EWA PATUREJ ◽  
MAGDALENA ZIELIŃSKA
Keyword(s):  
Control Agent ◽  
The Impact ◽  
Lecane Inermis

scholarly journals Biological Control of the Weedy Plant (Rumex crispus) at the Seedling Growth Stage by the Green Dock Beetle (Gastrophysa viridula)

2019 ◽  
Vol 28 (1) ◽  
pp. 21-31
Author(s):  
Khalid S. Alshallash Khalid S. Alshallash
Keyword(s):  
Biological Control ◽  
Seedling Growth ◽  
Growth Stage ◽  
Biological Control Agent ◽  
Dry Weight ◽  
Control Agent ◽  
Growth Stages ◽  
Rumex Crispus ◽  
Shoot Number ◽  
The Impact

In four glasshouse experiments, the effectiveness of the adult green dock beetle Gastrophysa viridula (Coleoptera: Chrysomelidae), at the effective number of applied individuals, for use as a biological control agent of curled dock, Rumex crispus (Polygonaceae) were studied. The feeding of the beetle was investigated at four different numbers of beetle (0, 1, 2, 3) and at four seedling growth stages of the plant, defined by the average of leaf area per plant (1-1.22 , 2-4.45, 3-11.56, and 4-71.52 cm2/plant). Grazing by one, two or three dock beetles did not result in a significant reduction in dock dry weight or shoot numbers at the youngest growth stage. However, both at later seedling growth stages were significantly affected (P ? 0.0001), at any beetles number. The increase of beetle numbers caused nonsignificant increased effect, in some trials, confirming the impact of a single beetle. Three months after beetle grazing, dock seedlings of first, second and third growth stages were not able to regrow, however, some plants at the 4th growth stage, re-emerged. This suggested that the highest effect of beetle's feeding occurs on the early seedling stages. Statistical analysis showed a positive correlation (0.77) between dry weight and shoot number at all the four seedling growth stages, thus confirming the impact of the beetle on both the dry weight and shoot numbers. Combining beetle grazing with other control methods at older dock seedling stages could, therefore, provide better suppression

Corrigendum to: The impact of rabbit haemorrhagic disease on wild rabbit (Oryctolagus cuniculus) populations in Queensland

2004 ◽  
Vol 31 (6) ◽  
pp. 651
Author(s):  
G. Story ◽  
J. Scanlan ◽  
R. Palmer ◽  
D. Berman
Keyword(s):  
Biological Control Agent ◽  
South Australia ◽  
Control Agent ◽  
Wild Rabbit ◽  
Isolated Populations ◽  
Rabbit Haemorrhagic Disease ◽  
Northern Edge ◽  
The Mean ◽  
Haemorrhagic Disease ◽  
The Impact

Rabbit haemorrhagic disease virus (RHDV) escaped from quarantine facilities on Wardang Island in September 1995 and spread through South Australia to Queensland by December 1995. To determine the impact of this biological control agent on wild rabbit populations in Queensland, shot sample and spotlight count data were collected at six sites. RHDV spread across Queensland from the south-west to the east at a rate of at least 91 km month–1 between October 1995 and October 1996. The initial impact on rabbit density appeared highly variable, with an increase of 81% (255 ± 79 (s.e.) to 385 ± 73 rabbits km–2) at one site and a decrease of 83% (129 ± 27 to 22 ± 18 rabbits km–2) at another during the first outbreak. However, after 30 months of RHDV activity, counts were at least 90% below counts conducted before RHDV arrived. Using a population model to account for environmental conditions, the mean suppression of rabbit density caused by rabbit haemorrhagic disease (RHD) was estimated to be 74% (ranging from 43% to 94% between sites). No outbreaks were observed when the density of susceptible rabbits was lower than 12 km–2. Where rabbit density remains low for long periods RHDV may not persist. This is perhaps most likely to occur in the isolated populations towards the northern edge of the range of rabbits in Australia. RHDV may have to be reintroduced into these populations. Further south in areas more suitable for rabbits, RHDV is more likely to persist, resulting in a high density of immune rabbits. In such areas conventional control techniques may be more important to enhance the influence of RHD.

scholarly journals Impact Assessment of Biological Control-Based Integrated Pest Management in Rice and Maize in the Greater Mekong Subregion

Insects ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 226 ◽  
Author(s):  
Dirk Babendreier ◽  
Min Wan ◽  
Rui Tang ◽  
Rui Gu ◽  
Justice Tambo ◽  
...  
Keyword(s):  
Biological Control ◽  
Integrated Pest Management ◽  
Pest Management ◽  
Smallholder Farmers ◽  
Biological Control Agent ◽  
Control Agent ◽  
Target Area ◽  
Positive Effects ◽  
The Difference ◽  
The Impact

The impact and sustainability of two interventions that have been formulated to introduce integrated pest management (IPM) into rice and maize crops in Southwestern China, Laos, and Myanmar between 2011 and 2016, and were assessed at the end of 2017. From 22 Trichogramma rearing facilities established during the interventions, 11 were still producing substantial quantities of biocontrol agents 1.5 years after project support had ended, while seven had stopped operations completely, and four were doing stock rearing only. Through the implementation of biological control-based IPM, slightly higher yields were achieved in maize and rice (4–10%), when compared to control farmers, but the difference was not statistically significant. However, the use of pesticides nearly halved when farmers started using Trichogramma egg-cards as a biological control agent. Support from either public or private institutions was found to be important for ensuring the sustainability of Trichogramma rearing facilities. Many of the suggested IPM measures were not adopted by smallholder farmers, indicating that the positive impacts of the interventions mostly resulted from the application of Trichogramma biological control agents. The following assessment suggests that further promotion of IPM adoption among farmers is needed to upscale the already positive effects of interventions that facilitate reductions in synthetic pesticide use, and the effects on sustainable agricultural production of rice and maize in the target area more generally.

The effect of medium on selected life-history traits in three clones of Lecane inermis (Rotifera) from activated sludge

2011 ◽  
Vol 63 (9) ◽  
pp. 2071-2076 ◽  
Author(s):  
Agnieszka Pajdak-Stós ◽  
Kocerba Wioleta ◽  
Edyta Fiałkowska ◽  
Beata Klimek ◽  
Janusz Fyda
Keyword(s):  
Life History ◽  
Chemical Composition ◽  
Mortality Rate ◽  
Activated Sludge ◽  
Mineral Water ◽  
Life History Traits ◽  
Culture Media ◽  
Control Agent ◽  
Egg Ratio ◽  
Lecane Inermis

We tested the effect of various culture media on life-history traits in three clones of the rotifer Lecane inermis, a potential bulking control agent. Four types of media were tested: a filtrate of activated sludge, mineral water, and each of these media enriched with molasses. The number of live and dead individuals and the number of amictic eggs were counted during the 14-day experiment, and the egg ratio (ER) and mortality rate were calculated. We found that the rotifers were well adapted to the changes in chemical composition of the medium and that the addition of molasses resulted in a significant increase in rotifer abundance. The highest ER was noted after two days, reaching a maximum of 4 eggs per female in treatments with filtrate and molassesenriched filtrate. The life-history traits varied depending on the clone and the medium, but all of the clones were able to survive and proliferate, even after 14 days of starvation.

scholarly journals Contrasting effects of the alkaloid ricinine on the capacity of Anopheles gambiae s.l. to transmit Plasmodium falciparum

2021 ◽  
Author(s):  
Domonbabele François de Sales Hien ◽  
Prisca S. L. Paré ◽  
Amanda Cooper ◽  
Benjamin K. Koama ◽  
Edwige Guissou ◽  
...  
Keyword(s):  
Growth Rate ◽  
Plasmodium Falciparum ◽  
Anopheles Gambiae ◽  
Ricinus Communis ◽  
Control Agent ◽  
Phenotypic Traits ◽  
Anopheles Coluzzii ◽  
Vector Borne Diseases ◽  
Anopheles Gambiae S.L ◽  
The Impact

Abstract Background: Besides feeding on blood, females of the malaria vector Anopheles gambiae s.l. readily feed on natural sources of plant sugars. The impact of toxic secondary phytochemicals contained in plant-derived sugars on mosquito physiology and on the development of Plasmodium parasites remains elusive. The focus of this study was to explore the influence of the alkaloid ricinine, found in the nectar of the castorbean Ricinus communis, on the mosquito ability to transmit Plasmodium falciparum. Methods: Females of Anopheles gambiae and its sibling species Anopheles coluzzii were exposed to ricinine through sugar feeding assays to assess the effect of this phytochemical on mosquito survival, the level of P. falciparum infection, and the growth rate of the parasite. Results: Ricinine induced a significant reduction in the longevity of both Anopheles species. Ricinine caused acceleration in the parasite growth rate with an earlier invasion of the salivary glands in both species. At a concentration of 0.04 g l-1 in An. coluzzii, ricinine had no effect on mosquito infection, while 0.08 g l-1 ricinine-5% glucose solution induced a 14% increase in An. gambiae infection rate. Conclusions: Overall, our findings reveal that consumption of certain nectar phytochemicals can have unsuspected and contrasting effects on key phenotypic traits that govern the intensity of malaria transmission. Further studies will be required before concluding on the putative role of ricinine as a novel control agent, including the development of ricinine-based toxic and transmission-blocking sugar baits. Testing other secondary phytochemicals in plant nectar will provide a broader understanding of the impact, which plants can have on the transmission of vector-borne diseases.

The population dynamics of competition between parasites

Parasitology ◽  
1985 ◽  
Vol 91 (2) ◽  
pp. 317-347 ◽  
Author(s):  
A. P. Dobson
Keyword(s):  
Population Dynamics ◽  
Parasite Species ◽  
Interference Competition ◽  
Population Level ◽  
Experimental Tests ◽  
Theoretical Models ◽  
Control Agent ◽  
Host Population ◽  
Free Living ◽  
The Impact

A number of published studies of competition between parasite species are examined and compared. It is suggested that two general levels of interaction are discernible: these correspond to the two levels of competition recognized by workers studying free-living animals and plants: ‘exploitation’ and ‘interference’ competition. The former may be defined as the joint utilization of a host species by two or more parasite species, while the latter occurs when antagonistic mechanisms are utilized by one species either to reduce the survival or fecundity of a second species or to displace it from a preferred site of attachment. Data illustrating both levels of interaction are collated from a survey of the published literature and these suggest that interference competition invariably operates asymmetrically. The data are also used to estimate a number of population parameters which are important in determining the impact of competition at the population level. Theoretical models of host-parasite associations for both classes of competition are used to examine the expected patterns of population dynamics that will be exhibited by simple two-species communities of parasites that utilize the same host population. The analysis suggests that the most important factor allowing competing species of parasites to coexist is the statistical distribution of the parasites within the host population. A joint stable equilibrium should be possible if both species are aggregated in their distribution. The size of the parasite burdens at equilibrium is then determined by other life-history parameters such as pathogenicity, rates of resource utilization and antagonistic ability. Comparison of these theoretical expectations with a variety of sets of empirical data forms the basis for a discussion about the importance of competition in natural parasite populations. The models are used to assess quantitatively the potential for using competing parasite species as biological control agents for pathogens of economic or medical importance. The most important criterion for identifying a successful control agent is an ability to infect a high proportion of the host population. If such a parasite species also exhibits an intermediate level of pathology or an efficient ability to utilize shared common resources, antagonistic interactions between the parasite species contribute only secondarily to the success of the control. Competition in parasites is compared with competition in free-living animals and plants. The comparison suggests further experimental tests which may help to assess the importance of competition in determining the structure of more complex parasite-host communities.

Influence of original host on chemotaxic behaviour and parasitism in Telenomus podisi Ashmead (Hymenoptera: Platygastridae)

2014 ◽  
Vol 104 (6) ◽  
pp. 781-787 ◽  
Author(s):  
R. Tognon ◽  
J. Sant'Ana ◽  
S.M. Jahnke
Keyword(s):  
Egg Parasitoid ◽  
Control Agent ◽  
Stink Bug ◽  
Natural Control ◽  
Field Bioassay ◽  
Original Host ◽  
Synthetic Sex Pheromone ◽  
Control Programmes ◽  
Telenomus Podisi ◽  
The Impact

AbstractThe egg parasitoid Telenomus podisi is a natural control agent of pentatomids, including Euschistus heros and Tibraca limbativentris, and success of parasitism is dependent upon the parasitoid finding the host. We tested the influence of host egg volatiles and the synthetic sex pheromone (zingiberenol) of T. limbativentris on chemotaxic behaviour of T. podisi, as well as, the impact of the original host on parasitoid selection. We used mated female T. podisi (48 h old) that emerged from the eggs of T. limbativentris or E. heros. The bioassays related to chemotaxy were performed in a Y-tube olfactometer and, to parasitism success, in laboratory and semi-field conditions. Telenomus podisi females that emerged from either the stink bug eggs, chose the pheromone more than control, or the pheromone plus eggs of E. heros in the semi-field bioassay, led to greater parasitism. Females that emerged from E. heros eggs chose egg volatiles from their original host rather than those from T. limbativentris, while females emerging from T. limbativentris, chose the egg volatiles of both hosts equally. When T. limbativentris was the original host, T. podisi females parasitized T. limbativentris over E. heros, while those emerging from E. heros exclusively parasitized E. heros eggs. These results demonstrated that T. podisi is more likely to parasitize the host in which it developed and that the original host can exert influence on the choice by those parasitoids. Understanding how the factors that mediate host–parasitoid communication are interrelated can help biological control programmes establish more effective and reliable tools with T. podisi.

Observations on the impacts of rabbit haemorrhagic disease on agricultural production values in Australia

2002 ◽  
Vol 29 (6) ◽  
pp. 605 ◽  
Author(s):  
Glen Saunders ◽  
Barry Kay ◽  
Greg Mutze ◽  
David Choquenot
Keyword(s):  
Agricultural Production ◽  
Best Practice ◽  
Control Agent ◽  
Wild Rabbit ◽  
Production Values ◽  
Rabbit Haemorrhagic Disease ◽  
Australian Case ◽  
Negative Impacts ◽  
Haemorrhagic Disease ◽  
The Impact

Rabbit haemorrhagic disease (RHD) may be the most important rabbit control agent to be made available to graziers in Australia since the advent of myxomatosis. Documenting the benefits of RHD to agricultural production values is an important process in determining best-practice strategies for the use of the disease in controlling rabbit populations. In this paper we review previous studies on the impact of rabbits and present recent Australian case studies that tracked the effects of RHD on agricultural production as the disease first spread across the continent. Indirect consequences of RHD, such as changes in costs of rabbit control as monitored through the use of 1080 (sodium monofluoroacetate), are reported. Potential negative impacts such as adverse effects on the wild rabbit fur and meat trade and in the spread of woody weeds are also discussed.

scholarly journals A Conceptual Model to Describe the Decline of European Blackberry (Rubus anglocandicans), A Weed of National Significance in Australia

Plant Disease ◽  
2014 ◽  
Vol 98 (5) ◽  
pp. 580-589 ◽  
Author(s):  
S. Aghighi ◽  
L. Fontanini ◽  
P. B. Yeoh ◽  
G. E. St. J. Hardy ◽  
T. I. Burgess ◽  
...  
Keyword(s):  
Biological Control ◽  
Biological Control Agent ◽  
Control Program ◽  
Global Scale ◽  
Control Agent ◽  
Cultural Control ◽  
Potential Threat ◽  
Plant Populations ◽  
National Significance ◽  
The Impact

Human activities have had an adverse impact on ecosystems on a global scale and have caused an unprecedented redispersal of organisms, with both plants and pathogens moving from their regions of origin to other parts of the world. Invasive plants are a potential threat to ecosystems globally, and their management costs tens of billions of dollars per annum. Rubus anglocandicans (European blackberry) is a serious invasive species in Australia. Herbicide and cultural control methods are generally inefficient or require multiple applications. Therefore, a biological control program using stem and leaf rust strains is the main option in Australia. However, biological control using rusts has been patchy, as host factors, climate, and weather can alter the impact of the rust at different locations. In 2007, Yeoh and Fontanini noticed that blackberry plants on the banks of the Donnelly and Warren rivers in the southwest of Western Australia were dying in areas that were being regularly monitored for the impact of rust as a biological control agent. The symptoms on blackberry became known as the disease “blackberry decline”. Continuous and intensive investigations are required to discover the different biotic and abiotic components associated with specific declines in plant populations. The only agent so far introduced to Australia for the biological control of blackberry is the rust Phragmidium violaceum.

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