Can Pumpkin Yield Be Increased by Supplementing Fields with Honey Bees or Bumble Bees? Jessica D. Petersen and Brian A. Nault Department of Entomology, Cornell University, New York State Agricultural Experiment Station, 630 W. North St., Geneva, NY 14456; phone: (315)-787-2423; email: jessica.petersen@cornell.edu Vine crops such as pumpkin, squash, cucumber and watermelon are some of New York ’s most valuable vegetable crops. These crops require pollination by bees or can produce higher yields when pollinated by bees. The most well known pollinator is the honey bee, Apis mellifera, and honey bee hives are placed in fields during the period these crops need to be pollinated. Unfortunately, Colony Collapse Disorder (CCD) continues to cause significant losses in populations of honey bees throughout the US, including New York. Worker bees from colonies affected by CCD leave their hives and never return. Neither the cause nor the cure for CCD has been positively identified. Fewer honey bee hives are now available for vine crop growers and the cost of renting hives has increased from approximately $30 per hive to ≥$75 per hive. Without a cure for CCD, it will continue to be difficult to find hives and more expensive to rent them, and growers will need other pollinators to service their vegetable crops. Previous research has shown that on an individual basis, the common eastern bumble bee (Bombus impatiens) was the most efficient pollinator of pumpkins, compared with other common species including the honey bee and squash bee. Not only is the bumble bee an efficient pollinator, but it is also abundant naturally, and available commercially making it a perfect candidate as an alternative pollinator to honey bees. Will Fruit Yield Increase if Bumble Bee Colonies are Placed in Fields? In the Finger Lakes Region of New York in 2011, we explored the potential of increasing pumpkin yields by supplementing fields with commercially produced common eastern bumble bees, honey bees or no bees. A total of 7, 10 and 7 commercial pumpkin fields were assigned bumble bees, honey bees or no bees, respectively. Bumble bees were acquired from Koppert Biological Systems, whereas honey bee hives were rented locally. Numbers of bumble bee colonies and honey bee hives placed in each field depended on its size. For bumble bees, one QUAD (= four colonies in a box) was placed on every 2 acres and 1 honey bee hive placed on every 3 acres. Fields ranged in size from 1.5 to 25 acres and were separated from each other by at least 1 mile. Regardless of treatment, fields were avoided if they were near other fields that had honey bee hives. The jack-o-lantern ‘Gladiator’ was selected as the variety for all locations. Ten ‘Gladiator’ seedlings were transplanted into each of three locations in the field (= total of 30 plants per field). Transplanting spanned a 3-week period in July. In September, when the crop was mature, all marketable fruit were counted and weighed. Data were analyzed using an ANOVA and treatment means were then compared using a t-test at P<0.05. The average fruit weight per pumpkin plant in fields supplemented with commercial bumble bees did not differ significantly from fruit weight in fields supplemented with honey bees or those that were not supplemented (Fig. 1). Although, there was a trend for numerically larger fruit yield to occur in bumble bee supplemented fields (16.5 lbs/plant), followed by honey bee supplemented fields (15.2 lbs/plant) and then non-supplemented ones (13.1 lbs/plant).