THE INFLUENCE OF CLIMATIC FACTORS ON THE INCIDENCE OF CONIESTA IGNEFUSALIS IN THE BAGAUDA AREA OF KANO STATE
THE INFLUENCE OF CLIMATIC FACTORS ON THE INCIDENCE OF CONIESTA IGNEFUSALIS IN THE BAGAUDA AREA OF KANO STATE
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Date
1999-05
Authors
EJEH, LAWRENCE
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Abstract
The growing problem of field pests and pesticide misuse in the savanna has been of
great concern among scientists and scholars. In the Nigerian Sudan savanna, where
traditional agriculture is widely practised, grain pest and use of pesticides are serious
constrainsts to millet production because of:
i) low literacy rates of farmers in the study area
ii) low income of the farmers to embark on effective chemical control, and
iii) poor user understanding by the few farmers that could afford chemical control.
This work related the relationship between the incidence of Coniesta-ignefusalis (a
major stemborer pest of millet) and environmental factors (weather factors) in the Bagauda
area in the Sudan savanna zone of Nigeria. The pest was monitored for three cropping
seasons (1995 to 1997) using pheromone traps on millet fields at the International Crops
Research Institute for the Semi-Arid Tropics (ICRISAT) station, Baguada, Kano, Nigeria
approximately on latitude 1 l°40oN and longitude 8°30'N.
Pest and weather data for the three cropping seasons (1995 to 1997) were statistically
analysed at three levels - the simple linear regression, the polynomial non-linear regression
and the multiple linear regression. The pest population was predicted using the multiple
linear regression approach.
The polynomial distribution was found to be the best method for determining
relationship between single or individual weather parameter- and pest incidence in the study
area. Results suggested that the availability of abundance of food and absence of natural
enemy has not been the only determinant in the incidence of the pests, and emphasise the
importance of weather condition in assessing these effect. The incidence of the pest in the
Nigerian savanna is weather dependent. Major climatic variables affecting the pest incidence
in the Sudan savanna are rainfall relative humidity, radiation and temperature. The influence
of rainfall was such that it correlated positively with both weekly and monthly data with r
values greater than 50% in all the years of study (i.e. the higher the rainfall the higher the pest
incidence). Rainfall amounts greater than 200mm were observed to hamper the pest
incidence. The effect of radiation was such that it correlated negatively with the pest
incidence for all the cases considered for 1995 and 1996 and 1997 monthly data with r-values
greater than 50%. Radiation was, however, not statistically significant both at 5% and 1%
level of significance for 1996 weekly data. Temperature influence was such that (Tavg)
correlated positively with the pest for all the years of study i.e. an increase in (Tavg) leads
to increase in the pest incidence (Tmin). (Tmax) is however, such that it correlated
negatively with the pest incidence (i.e. an increase in (Tmax) leads to a decrease in the pest
population) for 1996 data. The influence of relative humidity was such that it correlated
positively with the pest incidence in all the cases for all the years of study (i.e. an increase
in relative humidity leads to increase in the pest incidence). The weather variables do not
work in isolation but influences the pest incidence simultaneously.
Description
A THESIS PRESENTED TO THE POST GRADUATE SCHOOL IN PARTIAL FULFILLMENT OF THE AWARD OF BACHELOR OF SCIENCE. DEPARTMENT OF SOIL SCIENCE
FACULTY OF AGRICULTURE
AHMADU BELLO UNIVERSITY,
ZARIA
MAY, 1999
Keywords
INFLUENCE,, CLIMATIC,, FACTORS,, INCIDENCE,, CONIESTA IGNEFUSALIS,, BAGAUDA,, AREA,, KANO STATE.