Although honeybees are not overly efficient as pollinators of cucurbits like melons and pumpkins, they may still help improve yields and fruit quality. Research out of Illinois indicates that while populations of wild pollinators like bumblebees and carpenter bees were often sufficient to get good numbers of fruit set in small fields of pumpkins – adding honeybees substantially increased the average size of the fruit. This increase in fruit size is critical for crops like pumpkin that are sold by weight. The greatest improvement in fruit size was seen in the larger Jack-O-Lantern types of pumpkin. The increase in fruit size was attributed to more thorough pollination of each fruit in fields with lots of honeybees. The average flower was visited 25-35 times/day in fields with honeybees, compared to 10-15 times/day in fields with only native bees. If honeybees are used at the recommended rate of 2-3 colonies/ha, the cost of custom pollination runs to about $200/ha. As this service resulted in a 10,000 kg/ha (40%) increase in pumpkin yields, adding honeybees resulted in a $1800/ha increased in net crop value based on a wholesale price of $0.20/kg (typical price for Saskatchewan). Honeybee colonies should only be introduced into the field within a couple of days of peak flowering of the crop – otherwise the bees will find other, more favored pollen sources.
Source : Walters and Taylor (2006). HortScience 41: 370-373.