Browsing by Author "Abdallah, Mussa"

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Abundance and dispersal of the African black beetle, (heteronychus arator f.) (coleoptera: scarabaeidae) in Njombe region
(Sokoine University of Agriculture, 2016) Abdallah, Mussa
The invasive African black beetle Heteronychus arator F. is a serious pest of crops in Tropical and sub Tropical regions, including East Africa. Literature on ecology of this pest in Sub Saharan Africa is scarce. Abundance and dispersal of H. arator were determined in maize fields in Njombe Region, Southern highlands of Tanzania, from December 2013-May 2014. Soil sampling was done monthly to determine larvae abundance of H. arator. Similarly adults H. arator were collected monthly by hand picking and pitfall traps. Results showed that larvae were present throughout the growing season, with low population at planting and peak period coinciding with optimum soil moisture. The abundance of adults varied with sampling time, high peaks recorded during the onset of rainfall. Abundance of both larvae and adults were significantly (P < 0.001) affected by fertilizer type. High populations were observed in farmyard manure. Dispersal of H. arator was significantly (P < 0.001) affected by fertilizer type. A high number of beetles moved significantly longer distances in bio slurry than farmyard and inorganic fertilizer. The number of beetles significantly decreased with increase in rainfall (e = - 0.011, P <0.001, Exp [P] = 0.989). On the contrary, average temperature was positively associated with number of beetles [e = 0.748, P< 0.001, Exp (P) = 2.11], Larval abundance was significantly associated with rainfall [e = 0.0045, P < 0.03, Exp (P) = 1.004]. To study damage and control of H. arator, a separate experiment was set up with un treated, strip tillage, trap crop and insecticides. Results showed that damage by H. arator progressed from seedling to milk stage of maize in all plots. H. arator significantly (P < 0.001) affected above ground biomass, cob length, seed weight and grain yield but not cob weight of maize. Damage however differed significantly among treatments (P < 0.001) and across seasons (P < 0.001). Least damage was recorded in insecticide treated plots, and highest in untreated plots. The interaction between control method and time affected damage significantly (P < 0.001). The results provide useful input into management of H. arator under different fertilizer practices and weather conditions.