Browsing by Author "Belmain, S.R"

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The Ecorat project: Development of ecologically-based rodent management for the Southern African region
(European Vertebrate Pest Management Conference, 2011) Mulungu, L.S; Belmain, S.R; Dlamini, N; Eiseb, S; Kirsten, F; Mahlaba, T; Makundi, R; Malebane, P; Von Maltitz, E; Massawe, A; Monadjem, A; Taylor, P.; Tutjavi, V
The aim of this study was to carry out basic ecological research on rodent pests within subsistence-level agricultural communities in Africa. A range of techniques were used to collect baseline ecological knowledge on the temporal and spatial dynamics of rodent populations within rural farming communities in Tanzania, Swaziland and Namibia. These techniques included habitat surveys using removal trapping, capture-mark-recapture grids, and radio tracking of individually tagged animals. We also studied the local communities’ knowledge, attitudes and practices with respect to rodents and their control, the current cost of rodent damage and the costs/benefits of rodent control. Based on these data, a case-control trial was implemented to evaluate an ecologically-based rodent management (EBRM) intervention using intensive trapping coordinated at the community level. Results showed that intensive trapping using community based rodent management was cost-beneficial for rural farming communities, and these EBRM strategies are ecologically sustainable. Our research has shown that efficacy is more than 75% when compared to what farmers normally do to reduce rat populations. Farmer training and community cooperation are essential, and expertise in social anthropology to develop appropriate knowledge dissemination platforms must be supported.
Identifying the right plants for diverse biocontrol agents in tropical smallholder bean farming systems
(AJOL, 2021) Mkenda, P.A; Ndakidemi, P.A.; Stevenson, P.C; Arnold, S.E.J; Belmain, S.R; Darbyshire, I; Gurr, G.M
Biocontrol agents such as predators, parasitoids and pathogens potentially regulate crop pests populations. The agents feed directly on the pests, oviposit in the pest body or cause disease in the pest. While biocontrol has become a commercial enterprise in temperate horticulture, there is much less information on the biocontrol agents present in smallholder agricultural systems in the tropics and little knowledge about the importance of plant diversity in supporting their biocontrol activities. A standardized botanical survey walk combined with observations of plant- insect interactions was conducted on field margin vegetation of 24 smallholder fields of common beans (Phaseolus vulgaris L.) in three elevation zones of a tropical ecosystem. Sweep nets were also used to capture the biocontrol agents and stored in 70% ethanol for detailed taxonomy where identification in the field was not possible. A wide range of biocontrol agents interacting with the field margin plants, particularly flowering forbs were revealed. The most preferred field margin plants were Ageratum conyzoides, Commelina benghalensis, Pennisetum purpureum, Panicum maximum and Tripsacum sp. The most common biocontrol agents found to interact with the field margin plants were spiders (Araneae), long-legged flies (Dolichopodidae), predatory and parasitic wasps (Ichneumonids and braconids), hoverflies (Syrphidae) and assassin bugs (Reduviidae). Preferences of the biocontrol agents to certain plant species were similar across all three zones, indicating the importance of such plants in terms of food resources, shelter or nesting sites. The preference of the biocontrol agents to some plant species indicates the need to identify the specific benefits of these species to the biocontrol agents to determine whether non-crop habitat manipulation might enhance natural pest regulation.
Impact of spatio-temporal simulations of rat damageon yield of rice (Oryza sativa L.) and implications forrodent pest management
(Taylor & Francis, 2014-11-29) Mulungu, L.S; Lagwen, P.P; Mdang, M.E; Kilonzo, B.S; Belmain, S.R
Rodents often damage crops throughout the growing season, from germination to harvest, thus making it difficult to understand the cumulative effects of rodent damage for crops such as rice that are able to partially compensate for damage. Compensation can make it difficult to understand the impact of variable rodent damage in terms of when the damage occurs, its severity and thus when, whether and how rodent pests should be controlled. The compensatory responses of rice to simulated rat damage carried out at different growth stages and at different spatial levels of severity showed that higher yield was recorded during the wet season in comparison to the dry season. However, yield loss was observed during all cropping stages for all levels of simulated damage for wet and dry season crops, with significant compensation noted at the transplanting [14 days after sowing (DAS)] and vegetative (45 DAS) stages. Only damage at the maturity (110 DAS) stage resulted in significant reductions in rice crop yield. Seasonal differences suggest water availability was an important factor that perhaps enhanced rice production. The ability of rice to compensate for early rodent damage could potentially reduce a farmer's perception of damage. However, failing to control rodents at these earlier crop growth stages could lead to increased rodent populations at the time of maturity when compensatory effects are limited.