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Mrosso F.,Ilonga Agricultural Research Institute | Mwatawala M.,Sokoine University of Agriculture | Rwegasira G.,Sokoine University of Agriculture
Journal of Entomology | Year: 2014

This study investigated the effects of Lambdacyhalothrin 5% EC, insecticide, on three aphidophagous coccinellid species, Cheilomenes lunata, C. sulphurea and C. propinqua in cotton fields. The insecticide was tested on one 0.2 ha cotton field and an unsprayed control field of the same area. Lambdacyhalothrin 5% EC was sprayed at intervals of ten days with a total of six sprays in a season. Sampling followed a standard procedure in which twenty plants at the middle of the fields in each field were randomly selected and examined for coccinellids and aphids one day before and three days after each spray. Results show that Lambdacyhalothrin 5% EC has an impact on coccinellid populations. Larvae populations of coccinellids were reduced by 24, 28 and 49% for C. lunata, C. sulphurea and C. propinqua and 57, 50 and 39% in the first and second year, respectively. There were no significant differences in aphid populations between sprayed and unsprayed fields. These results suggest that coccinellids had a similar impact as Lambdacyhalothrin 5% EC in the reduction of aphid populations. The study concludes that Lamdacyhalothrin 5% EC could continue to be used as a strategic intervention to manage cotton aphids during the last sprays. If the insecticide is sprayed during the last sprays in the season, the coccinellids would have already finished their task of reducing the aphid populations in a particular field. © 2014 Academic Journals Inc.

Mulungu L.S.,Sokoine University of Agriculture | Lagwen P.P.,Sokoine University of Agriculture | Lagwen P.P.,Ilonga Agricultural Research Institute | Mdangi M.E.,Sokoine University of Agriculture | And 2 more authors.
International Journal of Pest Management | Year: 2014

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. © 2014, © 2014 Taylor & Francis.

Mulungu L.S.,Sokoine University of Agriculture | Mlyashimbi E.C.M.,Sokoine University of Agriculture | Ngowo V.,Rodent Control Center | Mdangi M.,MATI Ilonga | And 6 more authors.
International Journal of Pest Management | Year: 2014

We investigated the composition of the diet of the multi-mammate mouse, Mastomys natalensis, within irrigated rice and fallow field habitats at set time periods related to rice crop growth stages. In both habitats, vegetative plant material, i.e. leaves, stems and seeds, were the most abundant components of the rodent's diet, while other food types (invertebrates, fruits) were observed only in low quantities. We conclude that vegetative plant material and seeds were the main types of food consumed not only due to their relatively higher abundance in the environments under study but also because of the highly specialised herbivorous/granivorous nature of the dominant rodent species, M. natalensis. Thus, the introduction and expansion of continuous rice-cropping using irrigation in Tanzania is likely to be severely constrained by the presence of M. natalensis. In our opinion, field hygiene, including the removal of alternative food resources and nesting sites for M. natalensis near cropping areas, may help to both lower rodent population numbers and reduce immigration potential. Non-chemical rodent control methods such as trap barrier systems developed for lowland irrigated rice in south-eastern Asia should, we argue, be evaluated for their effectiveness under African conditions. © 2014 © 2014 Taylor & Francis.

Mulungu L.S.,Sokoine University of Agriculture | Ngowo V.,Rodent Control Center | Mdangi M.,MATI Ilonga | Katakweba A.S.,Sokoine University of Agriculture | And 5 more authors.
Pest Management Science | Year: 2013

BACKGROUND: Multimammate mice are the most important vertebrate pests in Sub-Saharan Africa and are also reservoirs of many zoonotic diseases, including sylvan plague. This study investigated the population dynamics and breeding patterns of this mouse in irrigated rice cropping systems in eastern Tanzania. RESULTS: The multimammate mouse, Mastomys natalensis, population varied with habitat and months. Fallow land had a more abundant population than rice fields. The highest population peak was observed during the dry season from July to October. Mastomys natalensis is sexually active throughout the year in the study area, although it reaches the highest level in June and December when rice is at the maturity stage. This suggests that breeding is highly influenced by the presence of a rice crop in both seasons. More juvenile individuals were recorded in August and September, indicating that they were produced in the previous breeding months. The sex ratio of M. natalensis was not skewed to either males or females, indicating that it was at parity. CONCLUSION: Rodent population dynamics during the study periods in all habitats indicated that high birth rates accounted for the rapid population growth and turnover. Regular control and sustainable operations are thus essential if rodent pest populations are to be kept within tolerable limits. © 2012 Society of Chemical Industry.

Mulungu L.S.,Sokoine University of Agriculture | Ngowo V.,Rodent Control Center | Mdangi M.E.,MATI Ilonga | Katakweba A.S.,Sokoine University of Agriculture | And 9 more authors.
Mammalia | Year: 2016

We investigated the recruitment and survival of the multimammate mouse, Mastomys natalensis, within irrigated rice and fallow field habitats at different time periods related to rice crop growth stages. Capture-Mark-Recapture data were collected for M. natalensis each month from June 2010 to May 2012, and both recruitment and survival were estimated in relation to land use (irrigated rice or fallow field) within the agro-ecosystem. Higher recruitment and survival were observed in rice fields than in fallow fields suggesting the relationship was compensatory when there was a higher quality food resource. In terms of management, farmers in the study area should implement management strategies in rice fields at both transplanting and maturity stages of crop growth in order to maintain recruitment and survival at low levels. © 2016 by De Gruyter 2016.

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