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 ◽  
...  

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.

Author(s):  
Khalid S. Alshallash Khalid S. Alshallash

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


Insects ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 226 ◽  
Author(s):  
Dirk Babendreier ◽  
Min Wan ◽  
Rui Tang ◽  
Rui Gu ◽  
Justice Tambo ◽  
...  

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.


2017 ◽  
Vol 108 (1) ◽  
pp. 48-57 ◽  
Author(s):  
Q. Li ◽  
S.V. Triapitsyn ◽  
C. Wang ◽  
W. Zhong ◽  
H.-Y. Hu

AbstractThe flee-weevil Orchestes steppensis Korotyaev (Coleoptera: Curculionidae) is a steppe eastern Palaearctic species, notable as a serious pest of elms (Ulmus spp., Ulmaceae), by feeding on the leaves (adults) or mining them heavily (larvae), especially of Ulmus pumila L. in Xinjiang, China. We have corrected the previous misidentifications of this weevil in China as O. alni (L.) or O. mutabilis Boheman and demonstrated that it is likely to be an invasive species in Xinjiang. Prior to this study, natural enemies of O. steppensis were unknown in Xinjiang. Resulting from field investigation and rearing in the laboratory during 2013–2016, seven parasitoid species were found to be primary and solitary, attacking larval and pupal stages of the host weevil. Pteromalus sp. 2 is the dominant species and also is the most competitive among the seven parasitoids, which could considered to be a perspective biological control agent of O. steppensis. Yet, the current control of this pest by the local natural enemies in Xinjiang is still currently inefficient, even though in 2016 parasitism was about 36% on U. pumila in Urumqi, so the potential for a classical biological control program against it needs to be further investigated, including an assessment of its parasitoids and other natural enemies in the native range of O. steppensis. The presented information on the natural enemies of this weevil can be also important for a potential classical biological control program against it in North America (Canada and USA), where it is a highly damaging and rapidly spreading invasive species.


EDIS ◽  
2013 ◽  
Vol 2013 (1) ◽  
Author(s):  
Rodrigo Diaz ◽  
Julio Medal ◽  
Kenneth Hibbard ◽  
Amy Roda ◽  
A. Fox ◽  
...  

Tropical soda apple is a prickly shrub native to South America. First reported in Glades Co., Florida in 1988, it later spread to Georgia, Alabama, Louisiana, Texas, Mississippi, Tennessee, North Carolina, and South Carolina. It is a major problem in pastures and conservation areas. Negative impacts of tropical soda apple include reduction of cattle stocking rates, competition with native plants, and the costs associated with its control. Dense thickets of the weed also can disrupt the movement of wildlife. This 4-page fact sheet provides a summary of the major steps of the successful biological control program against tropical soda apple in Florida. The article covers the importance of the weed, identification and biology of the biological control agent, rearing and release efforts, establishment and impact, and efforts to communicate the outcomes of the program to stakeholders. Written by R. Diaz, J. Medal, K. Hibbard, A. Roda, A. Fox, S. Hight, P. Stansly, B. Sellers, J. Cuda and W. A. Overholt, and published by the UF Department of Entomology and Nematology, November 2012. http://edis.ifas.ufl.edu/in971


1996 ◽  
Vol 86 (4) ◽  
pp. 397-405 ◽  
Author(s):  
S.T. Murphy ◽  
W. Völkl

AbstractThe Palaearctic pine aphids, Eulachnus agilis (Kaltenbach) and Eulachnus rileyi (Williams) have both been introduced into other continents where they have been reported causing damage to economically important pines. In Euorpe, they are attacked by the specialist parasitoid Diaeretus leucopterus (Haliday) which has been suggested as a possible biological control agent. Here we report on several aspects of the ecology of the parasitoid, conducted on E. agilis in Germany in 1993–94, to provide a more scientific basis for judging its potential for use in biological control. Parasitism of all instars in the field rarely exceeded 10% and was independent of host density. A high percentage of parasitized aphids were hyperparasitized. Measurements of the impact over 16 weeks in a greenhouse-release experiment showed that parasitism rates increased from 2 to 19% but were insufficient to suppress the aphid population below a damaging level. There was evidence of a density-dependent response. Studies on foraging behaviour showed that female parasitoids searched pines by quite extensive walks. There was no relationship between the number of aphids per tree and number of ovipositions, and the mean number of ovipositions per female per tree was 2.5 ± 0.4 eggs. The majority (55.1%) of encountered aphids did not respond to the parasitoids. However, female parasitoids attacked a much higher proportion of aphids that did respond but oviposition success on this group was poor. The number of aphid-infested needles on seedlings increased significantly owing to the parasitoid's foraging activity. On the basis of these results, it is suggested that D. leucopterus is only likely to be of benefit in biological control if used in conjunction with other complementary natural enemies.


Weed Science ◽  
2004 ◽  
Vol 52 (4) ◽  
pp. 628-633 ◽  
Author(s):  
Gary L. Hein ◽  
Robert G. Wilson

Canada thistle is a serious perennial weed found throughout the northern regions of the United States and Canada. The weevil,Ceutorhynchus litura(F.), was first released in Canada in 1965 as a potential biological control agent for Canada thistle; however, its impact as a control agent has been sporadic. The objective of this study was to characterizeC. lituraimpacts on the carbohydrate profile in Canada thistle roots through the growing season and to evaluate the potential for this biological control agent in causing stress to Canada thistle. Field plots, infested withC. litura, were established and extensively sampled forC. liturainfestations. By samplingC. litura–damaged and undamaged Canada thistle shoots–roots through the season, we were able to establish the profile of free sugars and fructans in the roots and compare these levels to the presence and extent of insect damage. Levels of all free sugars and fructans were consistently found to be depressed in roots fromC. litura–damaged shoots early in the summer during and shortly after the larval feeding period.Ceutorhynchus liturafeeding in Canada thistle shoots appears to disrupt the movement of photoassimilates from leaves to roots. Late-season levels of free sugars and fructans indicate that roots do recover from these depressed levels, and in several instances, significant overcompensation occurred in the damaged roots. Measurement of free sugars and fructans to identify sublethal impacts of control tactics may allow the strategic combining of complementary tactics to maximize the impact of stresses on Canada thistle.


Insects ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 231
Author(s):  
Pumo Cai ◽  
Yunzhe Song ◽  
Da Huo ◽  
Jia Lin ◽  
Huameng Zhang ◽  
...  

Fopius arisanus is a solitary endoparasitoid that parasitizes a variety of tephritid species. Native to the Indo-Australian region, it is currently exploited worldwide as a biological control agent due to its exceptional efficiency in reducing pest populations. The efficiency of any biological control program is affected by the host location ability of the parasitoids. The present study used a Y-tube olfactometer to test the behavioural responses of female F. arisanus to four fruit species which had undergone different types of damages: undamaged, damaged through Bactrocera dorsalis ovipositioning (i.e., infested), or different levels of mechanical damage. Our results suggest that F. arisanus females were significantly attracted to mangoes and pears (vs. purified air), regardless of their condition; however, whilst infested mangoes did not attract more female parasitoids compared to healthy or mechanically damaged fruits, infested pears attracted significantly more. For citrus fruits and peaches, oviposition damage caused them to be more attractive to parasitoid females. In terms of the longevity of the effects, infested mango fruits remained attractive for up to 5 days after infestation, whereas for infested peaches, pears, and citrus fruits, the attractiveness tended to decrease as time passed. Regarding mechanical damage, mango fruits that had undergone any intensity of damage were equally attractive to parasitoid females; however, peach and citrus fruits with high levels of mechanical damage were more attractive, and pears were found to be most attractive with slight mechanical damage. Additional to the above, we also tested the effect of insecticides on behavioural responses using mangoes. We found that the treatment of infested fruits with lambda-cyhalothrin and cypermethrin remained attractive to F. arisanus females, albeit to different extents, which is in contrast to spinosad, cyantraniliprole, and acetamiprid. Finally, we suggest that the host-searching behaviour of F. arisanus females is mainly mediated by oviposition-induced volatiles, either emitted from the fruit or left by the fruit fly.


Insects ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 183 ◽  
Author(s):  
Svetlana Boycheva Woltering ◽  
Jörg Romeis ◽  
Jana Collatz

Trichopria drosophilae is a pupal parasitoid that can develop in a large number of drosophilid host species including the invasive pest Drosophila suzukii, and is considered a biological control agent. We investigated the influence of the rearing host on the preference and performance of the parasitoid, using two different strains of T. drosophilae, reared on D. melanogaster or D. suzukii for approximately 30 generations. Host switching was employed to assess the impact of host adaptation on T. drosophilae performance. In a no-choice experimental setup, T. drosophilae produced more and larger offspring on the D. suzukii host. When given a choice, T. drosophilae showed a preference towards D. suzukii, and an increased female ratio on this host compared to D. melanogaster and D. immigrans. The preference was independent from the rearing host and was confirmed in behavioral assays. However, the preference towards D. suzukii increased further after a host switch from D. melanogaster to D. suzukii in just one generation. Our data indicate that rearing T. drosophilae for several years on D. melanogaster does not compromise its performance on D. suzukii in the laboratory. However, producing a final generation on D. suzukii prior to release could increase its efficacy towards the pest.


EDIS ◽  
1969 ◽  
Vol 2004 (8) ◽  
Author(s):  
William A. Overholt ◽  
Paul D. Pratt

In 1986, USDA/ARS scientists at the Invasive Plant Research Laboratory in Fort Lauderdale started a classical biological control program against melaleuca. The scientists recently released two insects as part of that program; the melaleuca weevil (Oxyops vitiosa (Coleoptera: Curculionidae)) and the melaleuca psyllid (Boreioglycapsis melaleucae (Hemiptera: Psyllidae)). This publication discusses the current distribution and dispersal rate of the weevil since in its introduction. This document is ENY-701, one of a series of the Entomology and Nematology Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Publication date: March 2004. https://edis.ifas.ufl.edu/in497


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