Cryptic species of a water hyacinth biological control agent revealed in South Africa: host specificity, impact, and thermal tolerance

2019 ◽  
Author(s):  
Iain D. Paterson ◽  
Julie A. Coetzee ◽  
Philip Weyl ◽  
Tamzin C. Griffith ◽  
Nina Voogt ◽  
...  
Keyword(s):  
South Africa ◽  
Biological Control ◽  
Cryptic Species ◽  
Host Specificity ◽  
Water Hyacinth ◽  
Thermal Tolerance ◽  
Biological Control Agent ◽  
Control Agent

Hybridization between Dactylopius tomentosus (Hemiptera: Dactylopiidae) biotypes and its effects on host specificity

2010 ◽  
Vol 100 (3) ◽  
pp. 331-338 ◽  
Author(s):  
C.W. Mathenge ◽  
P. Holford ◽  
J.H. Hoffmann ◽  
H.G. Zimmermann ◽  
R.N. Spooner-Hart ◽  
...  
Keyword(s):  
South Africa ◽  
Biological Control ◽  
Host Specificity ◽  
Biological Control Agent ◽  
Control Agent ◽  
Weed Species ◽  
Maternal Parent ◽  
Control Programs ◽  
Fitness Index ◽  
Biological Performance

AbstractDactylopius tomentosus is composed of biotypes adapted to different Cylindropuntia species. One biotype is an important biological control agent of C. imbricata in South Africa while another has the potential for the control of C. fulgida var. fulgida. These two weed species occur in sympatry in some areas of South Africa, so the introduction of the second biotype could result in hybridization, which, in turn, could impact on the biological control programs through altered host specificity and fitness of the hybrids. To anticipate what might happen, reciprocal crosses were made between the two biotypes, and the biological performance of the resultant hybrids was compared with that of each parental lineage on C. imbricata and C. f. var. fulgida. The biotypes interbred freely and reciprocally in the laboratory. Comparisons of crawler and adult female traits showed differences in performance that were dependent on the origin of the maternal and paternal genomes. However, when all traits were combined into a ‘fitness index’, both hybrids clearly outperformed the parental lineages. The increase in fitness shown by the hybrids over their maternal lineage was greater on the alternative host of the maternal parent than on the natural host of the maternal parent. Therefore, in areas where the two cacti occur in sympatry, hybridization between the biotypes is not expected to be detrimental to the biological control of either weed.

The pathogenicity of an Australian isolate of Acremonium zonatum to water hyacinth, and its relationship with the biological control agent, Neochetina eichhorniae

1987 ◽  
Vol 38 (1) ◽  
pp. 219 ◽  
Author(s):  
JC Galbraith
Keyword(s):  
Biological Control ◽  
Water Hyacinth ◽  
Biological Control Agent ◽  
Control Agent ◽  
Control Programme ◽  
Australian Isolate ◽  
Free Moisture ◽  
Neochetina Eichhorniae ◽  
Dry Conditions ◽  
The Individual

The first description of Acremonium zonatum on water hyacinth in Australia is made. Its pathogenicity was studied as part of the search for a microorganism already present in Australia which could be developed as a mychoherbicide to supplement the arthropod biological control programme in this country. Following inoculation with A. zonatum, extensive leaf infections developed, favoured by injury and free moisture, but new leaves continued to form. Feeding by the weevil, Neochetina eichhorniae, increased infection by A. zonatum in relatively dry conditions, but it is unlikely that this was due to feeding scars acting as ports of entry. A. zonatum spores were transported on the feet and in the digestive tract of the weevil. The growth of infected plants, estimated by standing crop, was reduced by 49% compared to the control. A further decrease occurred in infected plants infested by weevils, but the total reduction in growth was not equal to the sum of the individual effects of fungus and weevil. Infection did not develop in 15 other plant species inoculated with the Australian isolate of A. zonatum. Although not a virulent pathogen, A. zonatum has some favourable characteristics for consideration as a mycoherbicide and has not appeared antagonistic to N. eichhorniae in these studies. Its role probably lies in exerting a chronic stress on plants already under attack by arthropod biological control agents.

Invaded habitat incompatibility affects the suitability of the potential biological control agent Listronotus sordidus for Sagittaria platyphylla in South Africa

2018 ◽  
Vol 28 (5) ◽  
pp. 468-485 ◽  
Author(s):  
Grant D. Martin ◽  
Julie A. Coetzee ◽  
Mellissa Lloyd ◽  
Sinoxolo E. Nombewu ◽  
Mpilonhle S. Ndlovu ◽  
...  
Keyword(s):  
South Africa ◽  
Biological Control ◽  
Biological Control Agent ◽  
Control Agent

Stagonospora atriplicis. [Descriptions of Fungi and Bacteria].

2005 ◽  
Author(s):  
T. V. Andrianova
Keyword(s):  
South Africa ◽  
Biological Control ◽  
Czech Republic ◽  
New Zealand ◽  
Geographical Distribution ◽  
Biological Control Agent ◽  
Control Agent ◽  
Allenrolfea Occidentalis ◽  
Syzygium Guineense

Abstract A description is provided for Stagonospora atriplicis, a potential biological control agent of Atriplex and Chenopodium weeds. Information is included on the disease caused by the organism, its transmission, geographical distribution (Kenya, South Africa, Zimbabwe, Canada, USA, Colombia, Cyprus, Georgia, Kyrgyzstan, Russia, Australia, New Zealand, Austria, Belgium, Bulgaria, Czech Republic, Estonia, France, Germany, UK, Hungary, Italy, Latvia, Romania, Sweden, Ukraine and Hawaii) and hosts (Allenrolfea occidentalis, Atriplex spp., Chenopodium spp. and Syzygium guineense).

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