Yield of southern highbush blueberry (Vaccinium corymbosum) using the fly Calliphora albifrontalis (Diptera: Calliphoridae) as a pollinator

Southern highbush blueberry plants (Vaccinium corymbosum hybrid) from a commercial blueberry farm were placed in quarantine glasshouses and either exposed to adults of the western golden-haired blowfly Calliphora albifrontalis (Malloch) or no insects at all over a 21-week period. Laboratory reared C. albifrontalis were regularly released into one house to maintain a population of 1000-1500 flies. Flies could only obtain sugar from the plant flowers, and there was sufficient water from the leachate fraction draining out of each bagged plant. Berries were harvested at least twice weekly from the bushes over 21 weeks (46 harvest dates), and yield (both total berry weight and numbers) recorded. Temperature and humidity were very similar between the glasshouses, and plants were irrigated daily with 2.5-4 L/plant as per the producer's recommendations. Adult C. albifrontalis required at least 1.5 flowers/fly to survive. Both more berries (17.14 kg from 9108 berries vs. 10.43 kg from 6379 berries) and larger berries (1.88 vs. 1.63 g/berry) were produced by the bushes with adult C. albifrontalis present. Mature berries are ready to pick approximate to 10 weeks after flower opening. This study showed that yield between the two treatments began to differ 11 weeks after the flies were first released. Berry yield remained higher in the house with flies (11.29 kg from 6177 berries at 1.83 g/berry) compared with those plants without flies (4.98 kg from 3427 berries at 1.45 g/berry. Berry size was positively correlated with seed numbers. This is the first demonstration under controlled conditions of the ability of an Australian calliphorid blowfly to pollinate and increase yield of commercial blueberry bushes.