Browsing by Author "Nshubemuki, L."

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    The potential of classical biological control against leucaena psylid, heteropsylla cubana crawford in eastern Tanzania
    (2000) Madoffe, S. S.; Mhando, L.; Day, R. K.; Nshubemuki, L.
    The Leucaena psyllid HeteropsyHa cubana Crawford (Homoptera: Psyl/idae) has ~aused damaging ef fects to Leucaena leucocephala (Lam.) de Wit in Tanzania since its outbreak in 1992. Cultural, genetic and chemical controls havebel!n tried in some localised areas. In 1995, a hymenopterous parasitoids, Tamarixia leucaenae Boucek (Eupelmidae) was imported from Trinidad and Tobago for biological control of this pest in Tanga and Morogoro areas. Mummies of the parasitoid were recordedfrom the sixth week after release. The population declined to the lowest level between November 1995 and January 1996 before building-up again to about 10 and 11 mummies per shoot in July for Tanga and Morogogro respectively. Spread of the parasitoidwas fairly fast, and at about 16 months afterrelease it had covered over 300 Ian from the release sites. The spread and population build up indicates that this species has been established in Eastern Tanzania. In spite of declining shoot damage at about ten months after parasitoid release, it is probably too early to associate it with the parasitoid. Shoot damage was found to be more closely correlated to laboratory nymph count (r = 0.52) than to field nymph shoot numbers (r =\0.35). Several potential indigenous natural enemies were recorded in association with the psy/lid; however, their role as biological control agents needs further quantification.
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    Survival, growth, stem form and wood basic density of five Pinus Merkusii provenances at Buhindi, Mwanza, Tanzania
    (1998) Mugasha, A. G.; Mgalla, H.A.; Iddi, S.; Nshubemuki, L.; Chamshama, S.A.O.; Malimbwi, R. E.
    The performance of 16 Pinus oocarpa (including 5 now reclassified as Pinus patula spp. tecunumanii) provenances at Buhindi Mwanza, Tanzania: is evaluated in terms of survival, height growth, breast height diameter, basal area per ha, wood basic density and stem form. The final assessment was carried out at the age of 22 years. The main results of the study were: – Before angular transformation, survival varied from 77% (Rafael, Nicaragua) to 56% (Conacaste, Guatemala). However no significant difference (P >0.05) in survival was detected after such transformation. – Height growth showed significant differences (P< 0.05) at all ages. At 22 years the outstanding provenances were Siguatepeque (Honduras), Rafael (Nicaragua), and Zamorano (Honduras). Least height growth was shown by Bonete (Nicaragua) provenance. – Significant differences (P< 0.05) were detected in breast height diameter. Outstanding provenances were Yucul, Camelias (Nicaragua) and Mt. Pine Ridge-K49 (Belize). Least performers were Zamorano (Honduras) and Lagulnilla (Guatemala) provenances. – Significant differences (P< 0.05) were detected in basal area per ha development. The Bucaral (Guatemala) provenance was outstanding while least basal area development was recorded in the Conacaste, Lagunilla (Guatemala) and Siguatepeque (Honduras) provenances. – The Bucaral (Guatemala) provenance was significantly superior (P< 0.05) in wood basic density. Least wood basic density values were recorded from Camelias, Yucul, Rafael, Junquillo (Nicaragua), Angeles (Honduras) and the Lagumilla (Guatemala) provenances. – No significant differences (P >0.05) in stem form were observed. It is suggested that the 5 Pinus patula SCHIEDE and DEPPE ssp. tecunumanii (EQUILUZ and PERRY) provenances are likely candidates for species diversification in the Lake Victoria zone where the main plantation species is Pinus caribaea. However, noting that more than half of the natural distribution of P. oocarpa occurs outside central America, more provenances need to be tested to cover that extended range. Similarly, the sparse sampling of P. patula ssp. tecunumanii also needs additional representation. Restricting the results of this study to Pinus oocarpa, provenance ranking in diminishing order of performance gives: Bucaral (Guatemala), Zapotillo, Zamorano (Honduras), Chuacus (Guatemala), Siguatepeque (Honduras), Bonete, Junquillo (Nicaragua), Conacaste (Guatemala), Angeles (Honduras) and San Jose (Guatemala); and Lagunilla (Guatemala). In descending order of performance, suitable Pinus patula ssp. tecunumanii provenances are Mt. Pine Ridge (K49), Mt. Pine Ridge (K29), Rafael, Yucul and Camelias (Nicaragua).