MSc

The study entitled “Pests and diseases of stingless bee Trigona iridipennis Smith (Meliponinae: Apidae)” was conducted with the objective to study the pests and diseases associated with the stingless bees, their documentation, assessment of their damage and yield loss during the period 2013-14 at the AICRP on Honey bees and Pollinators, Department of Agricultural Entomology, College of Agriculture, Vellayani.
A survey was conducted in five Southern districts of Kerala viz., Thiruvananthapuram, Kollam, Pathanamthitta, Kottayam and Idukki. The pests of stingless bees documented were Hermitia illucens (Pathanamthitta) and Aethina sp. (Kottayam and Idukki). Predators recorded were Acanthaspis siva (Thiruvananthapuram) and Sycanus sp. (Kollam). Eight different predatory spiders, Thomisus projectus, Thomisus lobosus, Neoscona nautica, Menemerus bivittatus, Plexippus paykulli, Hersilia savignyi, Heteropoda venatoria and Crossopriza lyoni were recorded. Two pathogens viz., Paecilomyces variotii and Aspergillus niger were also observed.
Out of the 100 stingless bee colonies surveyed, only five colonies were infested with H. illucens in Pathanamthitta district whereas Aethina sp. was observed in four and five stingless bee colonies each from Kottayam and Idukki districts. The reduction in honey yield due to pests and diseases ranged from 93.93 to 96.76 per cent. Nine physiochemical parameters of stingless bee honey were observed, among which wide variation was observed in hydroxy methyl furfural and diastase activity between healthy and infested samples.
Regarding the nest architecture and defense mechanism of stingless bees, out of the four types of hives, majority of the beekeepers maintained stingless bee colonies in wooden hives (70.20 %) and mud pots (18.60 %). The incidence of pests/predators and diseases in stingless bee colonies showed that bamboo bits were free from pests and diseases incidence in all districts. In the case of wooden hives, short tubular hive entrance was dominant in all the districts. The length and width of entrance tube and number of guard bees in the short tubular type of entrance ranged from 3.74 to 4.63 cm, 1.49 to 1.93 cm and 6.91 to 9.00 nos. respectively. The materials used for constructing the hive entrances included natural materials viz., resins, waxes, tiny chips of wood, saw dust, sand, bee cadavers, leaves and vegetative parts, cerumen, wood and bark of trees. The hive entrance was closed after the dusk to prevent the entry of predators and pests into the hive during night time. The stingless bee hives were maintained at different heights from the ground level (3-5 ft, 6-8 ft, 9-11 ft and >12 ft) by the beekeepers. The hives maintained at 9-11ft above the ground level recorded the highest incidence of pests (5.10%) and predators (19.96%) whereas disease incidence was highest in boxes at 6-8 ft. None of the colonies maintained at 3-5 ft height from the ground level had pests/predator or disease incidence.
Based on the results of the study, two pests, two pathogens, two insect predators and eight spider predators were observed to cause damage to stingless bees. Observations on the nest architecture and defense mechanism showed that the incidence of pests and diseases was meagre in bamboo hives. Even though bamboo hives were less prone to the attack of pests and diseases, majority of the beekeepers used wooden hives for domesticating stingless bees since it is easier to handle during colony division, honey harvesting and periodical observations on need basis. Considering the height from the ground level, no incidence of pests, predators and diseases were recorded in the colonies maintained at 3-5 feet.