The population dynamics of an introduced tree, Sesbania punicea , in South Africa, in response to long-term damage caused by different combinations of three species of biological control agents

Oecologia ◽  
1998 ◽  
Vol 114 (3) ◽  
pp. 343-348 ◽  
Author(s):  
J. H. Hoffmann ◽  
V. C. Moran
Keyword(s):  
South Africa ◽  
Biological Control ◽  
Population Dynamics ◽  
Biological Control Agents

scholarly journals Seed survival of Australian Acacia in the Western Cape of South Africa in the presence of biological control agents and given environmental variation

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6816 ◽  
Author(s):  
Matthys Strydom ◽  
Ruan Veldtman ◽  
Mzabalazo Z. Ngwenya ◽  
Karen J. Esler
Keyword(s):  
South Africa ◽  
Biological Control ◽  
Seed Production ◽  
Western Cape ◽  
Biological Control Agents ◽  
Seed Survival ◽  
Quantitative Evidence ◽  
Before And After ◽  
Survival Proportion

Studies of invasive Australian Acacia have shown that many seeds are still produced and accumulate in soil stored seed banks regardless of the presence of seed-targeting biological control agents. This is despite claims of biological control success, although there is generally a lack of data on the seed production of invasive Australian Acacia before and after the release of the respective agents. We aimed to quantify seed production and seed survival of invasive Australian Acacia currently under biological control. The seed production and survival (proportion of aborted, predated and surviving seeds) of A. longifolia, A. pycnantha and A. saligna were each studied at four to five sites in the Western Cape of South Africa. The relationships between seed production and stand characteristics were determined and the relative effects of seed predation and abortion on seed survival were established. The investigated invasive Australian Acacia produced many seeds that survived the pre-dispersal stage despite long-term presence of released biological control agents. It was shown that seed crop size is the only significant factor influencing seed survival of the studied Australian Acacia species. Furthermore, the seeds surviving per tree and per square meter were related to tree size. No quantitative evidence was found to suggest that seed-reducing biological control agents are having an impact on the population dynamics of their Australian Acacia hosts. This study illustrates the importance of studying the seed ecology of invasive plants before biological control agents are selected and released.

scholarly journals The influence of two wildfires and biological control agents on the population dynamics of Melaleuca quinquenervia in a seasonally inundated wetland

2021 ◽  
Vol 14 (1) ◽  
pp. 3-8
Author(s):  
Philip W. Tipping ◽  
Melissa R. Martin ◽  
Jeremiah R. Foley ◽  
Ryan M. Pierce ◽  
Lyn A. Gettys
Keyword(s):  
Biological Control ◽  
Population Dynamics ◽  
Seedling Recruitment ◽  
Additional Treatment ◽  
Seed Rain ◽  
The Other ◽  
Melaleuca Quinquenervia ◽  
Biological Control Agents ◽  
Seedling Mortality ◽  
Sapling Growth

AbstractThe potential of Melaleuca quinquenervia (Cav.) S.T. Blake to reinvade cleared areas was evaluated over a 13-yr period that included two wildfires and the introduction of biological control agents. The first wildfire occurred in 1998 and was followed by a mean of 591.5 recruited seedlings m−2. Recruits from that fire were cleared 7 yr later in July 2005 for a second experiment to evaluate seedling recruitment into cleared areas. Seed rain, seedling recruitment and mortality, and sapling growth rates were measured in four plots located around individual large reproductive trees. A second natural wildfire in 2007 burned through those plots, leading to increases in seed rain followed by a pulse in recruitment of 21.04 seedlings m−2, 96.5% fewer than after the 1998 fire. Recruits in half of the plots around each tree were then treated with regular applications of an insecticide to restrict herbivory by biological control agents, while herbivory was not restricted in the other half. There was no difference in seedling mortality between treatments 1,083 d post-fire (2007) with 96.6% seedling mortality in the unrestricted herbivory treatment and 89.4% mortality in the restricted herbivory treatment. Recruits subjected to the restricted herbivory treatment grew taller than those in the unrestricted herbivory treatment, 101.3 cm versus 37.4 cm. Many of the recruits were attacked by the biological control agents, which slowed their growth. Although solitary M. quinquenervia trees retain some capacity to reinvade areas under specific circumstances, there was a downward trend in their overall invasiveness at this site, with progressively smaller recruitment cohorts due to biological control agents. Land managers should prioritize removing large reproductive trees over treating recently recruited populations, which can be left for many years for the biological control agents to suppress before any additional treatment would be needed.

scholarly journals First Screening of Entomopathogenic Nematodes and Fungus as Biocontrol Agents against an Emerging Pest of Sugarcane, Cacosceles newmannii (Coleoptera: Cerambycidae)

Insects ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 117 ◽  
Author(s):  
Marion Javal ◽  
John S. Terblanche ◽  
Desmond E. Conlong ◽  
Antoinette P. Malan
Keyword(s):  
South Africa ◽  
Biological Control ◽  
Chemical Control ◽  
Entomopathogenic Nematodes ◽  
Biocontrol Agents ◽  
Sugar Production ◽  
Biological Control Agents ◽  
Sugarcane Stalk ◽  
Reduce Sugar ◽  
Steinernema Yirgalemense

Cacosceles newmannii (Coleoptera: Cerambycidae) is an emerging pest of sugarcane in South Africa. The larvae of this cerambycid beetle live within the sugarcane stalk and drill galleries that considerably reduce sugar production. To provide an alternative to chemical control, entomopathogenic nematodes and fungus were investigated as potential biological control agents to be used in an integrated pest management system. The nematodes Steinernema yirgalemense, S. jeffreyense, Heterorhabditis indica, and different concentrations of the fungus Metarhizium pinghaense were screened for efficacy (i.e., mortality rate) against larvae of C. newmannii. The different biocontrol agents used, revealed a low level of pathogenicity to C. newmannii larvae, when compared to control treatments.

Seasonal abundance and parasitism of Mesoclanis seed flies (Diptera: Tephritidae) in South Africa, and implications for the biological control of Chrysanthemoides monilifera (Asteraceae) in Australia

1998 ◽  
Vol 88 (4) ◽  
pp. 407-414 ◽  
Author(s):  
P.B. Edwards
Keyword(s):  
South Africa ◽  
Biological Control ◽  
Nature Reserve ◽  
Seasonal Abundance ◽  
Western Cape ◽  
Flowering Period ◽  
Eastern Cape ◽  
Biological Control Agents ◽  
Kwazulu Natal

AbstractThe seasonal abundance and rates of parasitism of three species of Mesoclanis seed flies was studied in South Africa. The three species occur on Chrysanthemoides monilifera, and were recorded during most months of the year, whenever C. monilifera was flowering. At three sites in KwaZulu-Natal, numbers of eggs per capitulum of Mesoclanis polana Munro were highest on C. monilifera rotundata between June and November (winter/spring), towards the end of the main flowering flush. Parasitism of M. polana was between 50% and 90% for most of the year. Two other species of Mesoclanis (M. magnipalpis Bezzi and M. dubia Walker) occurred together on C. m. rotundata in the Eastern Cape (St Francis Bay), where parasitism during the year was between 55% and 95%. Peak numbers of eggs per capitulum (M. magnipalpis and M. dubia combined) occurred in May/June (winter), in the latter part of the main flowering flush. Mesoclanis magnipalpis was the only species recorded on C. m. pisifera in De Hoop Nature Reserve (Western Cape), where there was only one peak of oviposition (May/June), coinciding with the short and discrete flowering period of this subspecies. Parasitism was between 50% and 65%. At least nine species of parasitoid were reared from immature Mesoclanis stages. Eurytoma sp. (Eurytomidae) was a dominant parasitoid at all sites. Results are discussed in relation to the possible effectiveness of species of Mesoclanis seed flies as biological control agents of C. monilifera in Australia.

scholarly journals Insect Herbivores Associated with Nymphaea mexicana (Nymphaeaceae) in Southern United States: Potential Biological Control Agents for South Africa

2020 ◽  
Vol 103 (1) ◽  
pp. 54
Author(s):  
Megan K. Reid ◽  
Julie A. Coetzee ◽  
Martin P. Hill ◽  
Rodrigo Diaz ◽  
Lyn A. Gettys ◽  
...  
Keyword(s):  
United States ◽  
South Africa ◽  
Biological Control ◽  
Southern United States ◽  
Insect Herbivores ◽  
Biological Control Agents

scholarly journals The Biology and Ecology of the Diamondback Moth, Plutella xylostella (L.) in Eastern Ontario Revisited

2018 ◽  
Author(s):  
Tina Dancau
Keyword(s):  
Biological Control ◽  
Population Dynamics ◽  
Next Generation Sequencing ◽  
Plutella Xylostella ◽  
Diamondback Moth ◽  
Biological Control Agents ◽  
Review Of The Literature ◽  
Globally Distributed ◽  
Generation Sequencing

Diamondback moth, Plutella xylostella Linnaeus (Lepidoptera: Plutellidae) is a globally distributed pest on brassicaceous crops. This study aimed to follow up with aspects of earlier research, mainly to revisit the potential for overwintering of diamondback moth in the Ottawa area, to investigate present day population dynamics using a life-table approach and to use next generation sequencing to describe the diamondback moth microbiome. A review of the literature has reaffirmed that diamondback moth may not be capable of overwintering in Ottawa with populations likely migrant-driven. The population dynamics and parasitoid community appear to be unaltered after 65 years. The microbiome of diamondback moth larvae was dominated by Enterococcaceae, a family of bacteria hypothesized to aid in resistance and detoxification. This can provide opportunities for the introduction of new biological control agents and tools for diamondback moth management in the future.

Incidence of Aspergillus flavus in roasted and raw groundnuts from supermarkets and other vendors in Pietermaritzburg, South Africa and its management using biological control agents

2017 ◽  
Vol 50 (15-16) ◽  
pp. 815-827
Author(s):  
Kwasi Sackey Yobo ◽  
Phiwokuhle Mazibuko ◽  
Reshika Kallideen ◽  
Mark Delmege Laing
Keyword(s):  
South Africa ◽  
Biological Control ◽  
Aspergillus Flavus ◽  
Biological Control Agents
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