| dc.description.abstract | GENERAL ABSTRACT
Termites cause damage to agricultural crops, forests and natural vegetation, in several
parts of Africa. In Eastern Kenya, termites have been reported to cause between 50 to
100% yield losses in maize agro-ecosystems. General soil microfauna diversity
analyses have been done in Eastern region of Kenya but there is little information
documented on diversity and distribution of termites. Understanding the diversity of
termites allows implementation of appropriate management strategies and application
of species-specific control methods. Bio-control agents and cultural methods such as
intercrops have been reported to control termites, but there are no studies that
document the comparative efficacy of these control methods in maize agro-ecosystems
in Eastern Kenya. This study therefore aimed at determining the termite species
diversity in Machakos and Embu sub-counties. The effects of soil properties on
diversity of functional groups of termites, efficacy of various biological control agents
of termites and effect of intercropping maize with legumes and sorghum on infestation
levels of termites and damage of maize in Eastern region of Kenya were also evaluated.
Three different habitats comprising of maize crop farms, maize intercropped with
beans and natural vegetation were purposively sampled in Machakos and Embu
counties. From these habitats, termites were sampled for diversity analyses. Soil
samples were also taken from these sections and their physico-chemical properties
analyzed to determine their effects on functional diversity of termites. To determine
the effect of maize intercrops on infestation levels of termites, maize was intercropped
with soybeans, field beans and sorghum in different plots measuring 10m x 10m with
maize mono crop as a control. The experiment was carried out in Yatta sub-county in
Machakos county and it was laid out in a completely randomized block design with
each treatment replicated four times. The level of termite infestation was determined
during two seasons. Termites were sampled from 30cm x 30cm quadrats laid at an
interval of 5m along the transect. Additionally, five plants from each plot were also
randomly selected for assessment of termites’ infestation. Effect of bio-control agents
was determined by treating Macrotermes subhyalinus and Odontotermes badius with
biocontrol agents under laboratory conditions. There were five treatments replicated
four times. The treatments were Azadirachta indica, Metarhizium anisopliae, ants
predating on termites (Megaponera analis and Dorylus gribodoi), termidor (fipronil
9.1%) and distilled water as control. Termite diversity in Machakos and Embu counties
was assessed by Renyi diversity analysis. Analysis of variance using R Software was
used to compare the efficacy of various biological control methods and the effect of
intercropping maize on infestation levels of termites. The relationship between termite
functional diversity and soil properties was assessed using Canonical correspondence
analysis. Trinervitermes gratiosus was only found in Machakos county and occurred
in significantly greater numbers in natural vegetation macrohabitat compared to other
macrohabitats. The abundance of termite species and functional groups varied between
seasons and macrohabitats. Group II and IV were positively correlated to sand and silt,
respectively while group IIf was negatively associated with sand. There was a low
percentage of lodged plants in maize-sorghum intercrop which also had low population
densities of M. herus and Odontotermes badius in both seasons. In the bio-control
experiment, the mean percentage mortality caused by M. anisopliae in both O. badius
and M. subhyalinus were significantly lower compared to the rest of the treatments.
The information obtained from this study can be used in designing integrated termite
control strategies. | en_US |
