School of Pure and Applied Sciences

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Author: search.filters.author.Lagat, Zipporah OsiemoHas files: Yes

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    A new mite IPM strategy: predator avoidance behaviour resulting from the synergetic effects of predator release and acaricide‐treated nets
    (Wiley, 2018-10-26) Kungu, Miriam; Deletre, Emilie; Subramanian, Sevgan; Fiaboe, Komi Km; Gitonga, Linus; Lagat, Zipporah Osiemo; Thibaud, Martin
    Background: Tetranychus evansi and T. urticae spider mites are known major pests of Solanaceae. Smallholders in Africa rely heavily on pesticide treatments. However, farmers claim that pesticides are generally ineffective despite high-frequency sprays. New management solutions are thus urgently needed. This study assessed the efficacy of using acaricide-treated nets combined with predatory mite release for controlling spider mites. Results: The results showed the acaricide-treated net alone was more effective at reducing numbers of T. urticae than T. evansi. We observed the opposite for release of the predatory mite Phytoseiulus longipes. This difference could be explained by the specific dispersion strategies of the two spider mite pests; T. evansi is gregarious, whereas T. urticae dispersed rapidly. Joint application of both techniques resulted in a synergetic effect that reduced T. evansi and T. urticae spider mite numbers close to zero. The synergetic effect could be explained by predator avoidance behaviour of the prey spider mites, resulting in higher prey trapping and killing rates on acaricide-treated nets, while P. longipes fed on spider mite eggs. Conclusion: These techniques are profitable for smallholders as they are not expensive and avoid residues on the crop. © 2018 Society of Chemical Industry.
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    Open relationships in the castles of clay: high diversity and low host specificity of Termitomyces fungi associated with fungus-growing termites in Africa
    (International Union for the Study of Social Insects (IUSSI), 2010-08) Lagat, Zipporah Osiemo; Marten, Andreas; Kaib, M.; Gitonga, L. M.; Boga, H. I.; Brandl, R.
    In the African and Asian tropics, termites of the subfamily Macrotermitinae play a major role in the decomposition of dead plant material. Their ecological success lies in the obligate mutualism of the termites with fungi of the genus Termitomyces. Before the advent of molecular studies, the interaction with these fungi was poorly understood. Here, we combined available ITS sequence data from West, Central, and South Africa with data of 39 new samples from East Africa to achieve the most comprehensive view of the diversity and host specificity of Termitomyces symbionts across Africa to date. A high amount of sequence divergence in the ITS sequences was found; 11 different Termitomyces lineages in East Africa and >30 lineages across Africa were identified, and the expected diversity is estimated to be about 41 lineages. The fungal lineages belong to four major clades, each almost exclusively associated with one termite host genus. Analysis of molecular variance revealed that 40% of the ITS sequence variation occurred between host genera, indicating close co-evolution at this level. However, within host genera, fungal lineages and haplotypes were frequently shared among host species and sampling localities, except for fungal symbionts of Odontotermes. Horizontal transmission of fungal symbionts may facilitate the transfer of haplotypes and species among hosts. However, at present, we have little understanding of the maintenance of specificity at the genus level. Possible explanations range from substrate specificity of fungi to an active selection of fungi by termites.
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