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Abstract
ABSTRACT
Pesticides are chemicals widely used in agriculture to control diseases and to help increase crop
yield. Pesticides in particular insecticides can be very beneficial but have also been found to have
harmful side effects on non-target insects. The effects of pesticides are not simply linear but
complex through their interactions with a large variety of biotic and abiotic factors. Pesticides is
a general word that describes numerous groups of insecticides, fungicides, herbicides, garden
chemicals, household disinfectant sand rodents that are operated to both destroy and protect from
pests. Rhizobacteria are root associated bacteria that can have detrimental, neutral or beneficial
effect on plant grow. Nitrogen fixation is one of the beneficial processes performed by
rhizobacteria. Plant growth promoting rhizobacteria were first identified by Kloepper and
Schroth et al., (1978) to be soil bacteria that colonize the roots of plants following inoculation
onto seed and that enhance plant growth. Pesticides that persist in soil may have a long-lasting
impact on Rhizobial survival and function. The soil was sprayed with the combination of the
chemicals (Haloxyfop R Methyl Ester and Dichlovos) after they were diluted. Soil samples were
obtained from the University of Benin (UNIBEN), life science land and were wrapped in a clean
sterile polythene bag and labelled control and mixture of both chemicals. The materials for the
experiment were sterilized, the differential agars were prepared and the soil samples were diluted.
Distinct colonies were identified after growth were observed on the nutrient agar, these were
restreaked on a freshly prepared agar to obtain the pure culture and incubated at 37°C for 24
hours. Growth on Bacillus cereus agar and Eosin methylene blue agar were observed by colony
forms, colours and spore morphology. Using the nitrogen free medium, pure cultures were
inoculated and incubated at 28°C for 1-7 days and growth on these plates confirms the ability to
fix nitrogen. The results showed a gradual increase in the microbial count across 28 days (from
3.8×104 ± 707.11 to 4.9×104 ± 4949.75). Also there was little or no effect on plant growth
promoting rhizobacterial activities of isolated microorganisms such as Pseudomonas aeruginosa,
Escherichia coli and Bacillus subtilis. Chemicals that have little or no effects on the plant
growth promoting rhizobacterial abilities of microorganisms should be used on farmlands.
Pesticides are chemicals widely used in agriculture to control diseases and to help increase crop
yield. Pesticides in particular insecticides can be very beneficial but have also been found to have
harmful side effects on non-target insects. The effects of pesticides are not simply linear but
complex through their interactions with a large variety of biotic and abiotic factors. Pesticides is
a general word that describes numerous groups of insecticides, fungicides, herbicides, garden
chemicals, household disinfectant sand rodents that are operated to both destroy and protect from
pests. Rhizobacteria are root associated bacteria that can have detrimental, neutral or beneficial
effect on plant grow. Nitrogen fixation is one of the beneficial processes performed by
rhizobacteria. Plant growth promoting rhizobacteria were first identified by Kloepper and
Schroth et al., (1978) to be soil bacteria that colonize the roots of plants following inoculation
onto seed and that enhance plant growth. Pesticides that persist in soil may have a long-lasting
impact on Rhizobial survival and function. The soil was sprayed with the combination of the
chemicals (Haloxyfop R Methyl Ester and Dichlovos) after they were diluted. Soil samples were
obtained from the University of Benin (UNIBEN), life science land and were wrapped in a clean
sterile polythene bag and labelled control and mixture of both chemicals. The materials for the
experiment were sterilized, the differential agars were prepared and the soil samples were diluted.
Distinct colonies were identified after growth were observed on the nutrient agar, these were
restreaked on a freshly prepared agar to obtain the pure culture and incubated at 37°C for 24
hours. Growth on Bacillus cereus agar and Eosin methylene blue agar were observed by colony
forms, colours and spore morphology. Using the nitrogen free medium, pure cultures were
inoculated and incubated at 28°C for 1-7 days and growth on these plates confirms the ability to
fix nitrogen. The results showed a gradual increase in the microbial count across 28 days (from
3.8×104 ± 707.11 to 4.9×104 ± 4949.75). Also there was little or no effect on plant growth
promoting rhizobacterial activities of isolated microorganisms such as Pseudomonas aeruginosa,
Escherichia coli and Bacillus subtilis. Chemicals that have little or no effects on the plant
growth promoting rhizobacterial abilities of microorganisms should be used on farmlands.
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