Masters Thesis
The efficacy of insecticides used for cotton insect pests management were investigated in
Maswa district from November 2018 to April 2019. The aim was improvement of cotton
productivity through use of appropriate insecticides at recommended rates of application.
The experiment was laid out as factorial in Randomized Completely Block Design
(RCBD) with three replications in different locations, i.e. Shanwa primary, Maswa girls
and Binza Secondary. The main plots consisted of three different insecticide
concentrations, i.e. 0.8 of actual, 1.0 actual, and 1.2 of actual, mls while the subplots
constituted the nine types of insecticides. These insecticides were applied three times
according to the recommended application regime and the economic thresholds of each
major cotton insect pest observed. Data collected were subjected to the ANOVA technique
using SAS 9.3 statistical software and followed by Least Significant Difference (LSD0.05)
means separation. Cotton insect pests dominant were Aphids followed by ants, which was
one a beneficial. All the insecticides and rates of application tested decreased cotton insect
pests densities and boll damage resulting in increased seed cotton yield when compared
with control. Attakan, Confidor, Thunder and Duduba were highly effective against
sucking insect pests of cotton. Based on Economic threshold (ET), dominant insect pests
were; Aphids (20% of infested plants) and American bollworm (0.5 flared squares per
plant) which was determined in order to initiate control measures which lead to increases
in seed cotton production per area. ET rationalizes the use of insecticides to overcome
inappropriate choices of insecticides, wrong timing of application, poor dosages and
limited knowledge on scouting pests and decision making largely contribute to
ineffectiveness of insecticides. Insecticides application therefore should be rotated in order
to lower insect pest abundance.