The southwestern part of Nigeria is a tropical rainforest region having many local beekeepers. These beekeepers have experienced decline in colony establishment in the recent past. A study carried out in Lagos, Ogun and Osun states between December 2009 and September 2011 examined 14 randomly selected commercial bee farms for problems associated with decline in colony establishment. Sampling and treatments were split equally between each apiary and three colonies were selected in each. All the colonies were housed in Tanzania/local top bar hives. There were 58.34, 44.84 and 40.61 average percentage declines in colony establishment in Lagos, Ogun and Osun States, respectively. Presence of pests and diseases, pesticide poisoning, poor hive and seasonal management, ecological problem and lack of queen rearing were potential problems identified by the beekeepers. All the apiaries had pests like Crickets, Ants (
Companotus pennsylvanicus), Small Hive beetle (
Aethina tumida), Termites (
Macrotermes spp) and Spider (
Lactrodectus mactan).
Varroa
mite infestations were found in 33 (78.57%) of apiaries sampled. There was no significant difference between the levels of
Varroa infestation in all the colonies during the dry and wet seasons at confidence interval of 95 percent (t = 1.542, df = 13, p = 0.147 (p> 0.05).
Nosema spores were found in 27 (64.29%) colonies examined. The number of spores range from 16 x 10
3 to 30.4 x 10
3. There were no significant differences in the infection from colony to colony, apiary to apiary and between dry and wet seasons (
t = - 0.094
df = 11, P = 0.927 (P > 0.05). Diseases like American and European foulbrood were absent while chalkbrood disease was prevalent. Environmental factors of high temperature, high rainfall and high relative and hive humidity enhanced the spread of pests and disease pathogens. Many insecticides were constantly applied by the farmers on the crops in the surrounding farmland. Two of the commonly used insecticides DDVP (Dichlorvos) and Cyperforce (Cypermetrin) were discovered to have increased mortality on worker honey bees with progressively larger doses. It was obvious that insecticide toxicity had a significant effect on the colony. Hence, ecological and management problems had contributed to the decline in colony establishment in this area.
