Browsing by Author "Sibuga, K.P."

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Comparative performance of low and high volume herbicide sprays for weed control in lowland rainfed rice (Oryza satica L)
(2002) Sibuga, K.P.
Pre- and post emergence herbicides, were evaluated for weed control in lowland rice -(Oryza sativa L)) in field trials during 1998 and 1999 cropping seasons. Herbicides; were applied at high volume (416 1/ha) using a knapsack sprayer (CP 15), or at low volume (30 l/ha) using a controlled droplet application (c.da.) equipment. the Herbi-4 sprayer. The herbicides tested at varying dosage rates were saturnvalor. Ronstar and Basagran PL 2. In both seasons. Cyperus rotundus L (purple nutsedge) was the most dominant weep spp. A variety of broad leaf and grass weeds were also observed. All herbicides used stunted the growth of purple nutsedge but none was able to control the weed completely. Hand-weeding was most effective in reducing weed growth and resulted in the highest 2-season average yields in rice (2. Z t/ha). Rice yields were reduced to their lowest levels averaging 1.1 1.1 t/ha where no weeding was done. All the herbicide treatments resulted in similar (p>0.05) but relativeiy lower yields to handweeding in both years. These results suggest that the high volume formulations of Satumvalor and Basagran PL 2 and Ronstar can be succesfully used for weed control in rice using a c.d.a equipment
Deriving appropriate pest management technologies for smallholder tomato (Solanum lycopersicum Mill.) growers: A case study of Morogoro, Tanzania
(Journal of Animal & Plant Sciences, 2010) Maerere, A.P.; Sibuga, K.P.; Bulali, J.E.M.; Mwatawala, M.W.; Kovach, J.; Kyamanywa, S.; Mtui, H.D.; Erbaugh, M
The current standard farmer practice for insect pests and disease control in tomatoes is routine weekly pesticide sprays which are not always required. Field experiments were conducted at Morogoro, Tanzania to evaluate the effect of seven management practices (sub plots) on pest incidence and yields during May-September 2007 (normal production season) and October 2007 - February 2008 (off-season) using two determinate varieties CALJ and Tanya (main plots) in a RCBD with five replications. Practices involving intercropping with Vigna unguiculata or Cleome gynandra, application of fertilizer or mulch were severely infested by insects particularly thrips (Frankinlla occidentalis) which averaged 30 insects/plant at 64 days after transplanting. The standard and integrated pest management (IPM) practices led to similar low levels of insect pest and disease control though in the IPM only 3 pesticide sprays were applied compared to 10 for the standard practice. In the normal season, disease incidences of early blight (Phytophthrora infestans), late blight (Altenaria solani), leaf spot (Septoria lycopersici) and leaf curl were low (<10%) except for fertilizer and mulch treatment where incidences were close to 50%. The greatest fruit damage (>50%) was ascribed to Helicoverpa armigera. Purple nutsedge (Cyperus rotundus), the most dominant weed, was initially controlled by pre-transplanting application of Round-up® and mulch suppressed the growth of the dominant broadleaf weeds Digera muricata (false amaranth); Amaranthus spp (pigweeds) and Commelina benghalensis (wondering jew). In the normal season, tomato yields with current farmer practice were highest averaging 18.5 t/ha which was not significantly different (P=0.05) from mulch application (14 t/ha) followed by IPM (12.1 t/ha). Similarly, in the off-season crop, yields were highest and similar for mulch and standard practice (4.8 t/ha) followed by IPM (3.4 t/ha). Farmers selected mulch application and IPM for on-farm demonstration to verify production costs and benefits.
Effect of seed treatments and mulch on seedborne bacterial pathogens and yield of tomato (Solanum lycopersicum Mill.) in Tanzania
(Journal of Animal & Plant Sciences, 2010) Mtui, H.D.; Bennett, M.A.; Maerere, A. P.; Miller, S.A.; Kleinhenz, M.D; Sibuga, K.P.
The study was conducted to assess the presence of seedborne bacteria in four tomato seedlots, the efficacy of seed treatments in reducing bacterial contamination and to determine influence of seed treatment or mulch on crop development and yield. Tomato seedlots were treated using hot water, chlorine, and Ridomil® followed by seedborne bacteria pathogen detection. Seedlings from treated and non-treated seedlots were grown in the field in mulched and non-mulched plots. Results showed that all seedlots assessed were contaminated with Clavibacter michiganensis subsp. michiganensis (CMM), Xanthomonas campestris pv. vesicatoria (XCV) and Pseudomonas syringae pv. tomato (PST). ‘Tanya G1’, ‘Tanya G2’ (first and second generation farmer-saved seeds respectively) and commercial ‘Cal J’ seedlots were more highly contaminated with XCV than commercial ‘Tanya’ seedlot. ‘Tanya G2’ had the highest PST contamination but did not differ from other seedlots for CMM. Chlorine and hot water significantly reduced bacterial populations on seeds. Ridomil seed treatment did not affect bacterial contamination compared to the untreated control. Marketable fruit yield differed statistically (P = 0.01) for commercial ‘Tanya’ and ‘Cal J’ seedlots. Commercial ‘Tanya’ and ‘Tanya G1’ had higher yields compared to ‘Cal J’ and ‘Tanya G2’. There was no statistical difference (P = 0.05) among seed sources with respect to incidence of blossom end rot (BER) and sunscald disorders. Chlorine and hot water treatments led to higher number of fruits per plant and increased yield compared to Ridomil treatment and the control. Seed treatment had no significant influence on BER. Plants from hot water treatment produced statistically fewer sunscald fruits compared to control, because of more vigorous growth that provided protective shade. The effect of mulch on the yield components and in reduction of sun-scalded fruits was highly significant (P = 0.0001). Seed treatment and mulch therefore can reduce disease infestation and improve tomato yield.