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 103 to 30.4 x 103. 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