Biological Control of<i>Leucaena leucocephala</i>(Lam.) de Wit (Fabaceae) in South Africa: A Tale of Opportunism, Seed Feeders and Unanswered Questions

Olckers, T.

doi:10.4001/003.019.0219

Cited by 41 publications

(55 citation statements)

References 10 publications

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“…), in many cases they have created huge environmental problems and have proved almost impossible to eradicate (e.g., Acacia mearnsii, Leucaena leucocephala and Prosopis spp.) [5][6][7]. Jatropha is considered a noxious weed in parts of Australia and has been targeted for biological control [8] and was banned in South Africa precisely due to this concern [9].…”

Section: Introductionmentioning

confidence: 99%

The Rise, Fall and Potential Resilience Benefits of Jatropha in Southern Africa

2014

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Jatropha is the latest in a list of "miracle crops" that have been promoted in southern Africa for their perceived development benefits. This was based on promises of high yields, low water requirement, ability to grow on marginal land and lack of competition with food. In less than 10 years, tens of thousands of hectares were acquired for jatropha plantations and thousands of hectares were planted, most of which are now unused or abandoned. Overestimations of jatropha yields coupled with underestimations of the management costs have probably been the prime contributors to the collapse of most jatropha projects in southern African. However, a few projects still survive and show signs of possible long-term sustainability. We consider two such projects, a smallholder-based project in Malawi and a large-scale plantation in Mozambique. Though their long-term sustainability is not proven, both projects may increase resilience by diversifying household income streams and contributing to national fuel security. By identifying what seems to be working in these projects we provide insights as to why other projects may have failed in southern Africa and whether there is still place for jatropha in the region. In essence can jatropha still enhance local/national resilience or are jatropha's benefits just a myth? OPEN ACCESSSustainability 2014, 6 3616

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Section: Introductionmentioning

confidence: 99%

The Rise, Fall and Potential Resilience Benefits of Jatropha in Southern Africa

2014

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“…This species is capable in thrives because this species was very adaptive to the dry climate condition with the lower rainfall between 500-3500mm and in soil condition with the lower nutrient [22,23,24]. This species introduces to Riung for the first time in 1990s because of the advantages especially soil conservation, erosion control and the leaves for feed and the branches for firewood [22,25,23,26]. The existing of this species have been the serious treatment for biodiversity in Ontoloe Island because the power of this species in killing the native plants and capable to change the structure and composition of vegetation in Ontoloe Island.…”

Section: Discussionmentioning

confidence: 99%

The invasive alien plants threatened the balance of ecosystem in conservative area in Ontoloe Island, Flores-Indonesia

Wake

Soeprobowati

Jumari

2018

J. Phys.: Conf. Ser.

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“…de Wit (Fabaceae), commonly called leucaena, is a small tree that occurs naturally in Mexico and Central America but has become invasive in more than 120 countries with tropical, subtropical and warm temperate climates (see review by Olckers 2011 and references therein). As occurred in several countries worldwide, L. leucocephala was introduced into South Africa for agroforestry (Olckers, 2011), and has also become invasive in riparian vegetation, wetlands, forest habitats and disturbed areas (Henderson, 2001(Henderson, , 2007. Since the plant is a typical 'conflict species', with both beneficial and harmful attributes (Orwa, Mutau, Kindt, Jamnadass, & Simons, 2009), biological control efforts have focused on the deployment of seed-feeding agents to counteract its excessive seed production (Olckers, 2011).…”

Section: Introductionmentioning

confidence: 99%

Does height of exposure in the canopy influence egg mortality inAcanthoscelides macrophthalmus(Coleoptera: Chrysomelidae), a biological control agent ofLeucaena leucocephalain South Africa?

Ramanand

Olckers

2013

Biocontrol Science and Technology

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Introduced into several countries worldwide for agroforestry, Leucaena leucocephala (Lam.) de Wit is a typical 'conflict species' that invades several riparian, forested and disturbed habitats in South Africa. The seed beetle Acanthoscelides macrophthalmus (Schaeffer) (Chrysomelidae: Bruchinae) was subsequently deployed as a seed-reducing agent to offset its excessive seed output. However, exploratory egg-exposure trials, in which native Acacia s.l. trees were used as 'surrogate host plants', suggested that high egg mortality is reducing the beetle's impact. The aims of this study were to (1) verify this suspicion by comparing the mortality of eggs exposed in L. leucocephala and Acacia nilotica (L.) Willd ex Del. stands and (2) determine whether height of exposure in the canopy (i.e. oviposition site selection) influences the different mortality factors. Although lower than in the exploratory trials, egg mortality was considerable, ranging from 30 to 50% in most instances. While unaffected by height of exposure, the overall egg mortality (i.e. all factors) was significantly lower in seeds exposed on L. leucocephala. Mortality was not only mostly attributed to parasitism (51% of mortality), but also predation (30%) and unknown factors (19%). While unexplained mortality and predation were not influenced by tree species or height of exposure, parasitism increased significantly with height above ground and was significantly lower in seeds exposed on L. leucocephala. Egg mortality is thus one of several factors that appears to be limiting the efficacy of A. macrophthalmus in South Africa.

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Biological Control ofLeucaena leucocephala(Lam.) de Wit (Fabaceae) in South Africa: A Tale of Opportunism, Seed Feeders and Unanswered Questions

Cited by 41 publications

References 10 publications

The Rise, Fall and Potential Resilience Benefits of Jatropha in Southern Africa

The Rise, Fall and Potential Resilience Benefits of Jatropha in Southern Africa

The invasive alien plants threatened the balance of ecosystem in conservative area in Ontoloe Island, Flores-Indonesia

Does height of exposure in the canopy influence egg mortality inAcanthoscelides macrophthalmus(Coleoptera: Chrysomelidae), a biological control agent ofLeucaena leucocephalain South Africa?

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