ORCHARD EVALUATION OF THREE COMMERCIAL HONEY BEE ATTRACTANTS FOR USE IN POLLINATING APPLE BLOSSOMS AND SUBSEQUENT FRUIT SET (Progress Report for 1999)
Dr. James E. Tew, Associate Professor
Entomology Department
OARDC/The Ohio State University, Wooster, Ohio
tew.1@osu.edu
Dr. David C. Ferree, Professor
Department of Horticulture and Crop Science
OARDC/The Ohio State University, Wooster, Ohio
ferree.1@osu.eduMethod:
The method was the same as the study conducted in the spring of 1998. A 20 A test orchard, was partitioned into four quadrants with an untreated buffer between test plots. One plot remained untreated as a control. At recommended label rates and using air blast sprayers, three commercial attractants, Bee Scentä , Bee Hereä , and Fruit Boostä , were applied to individual orchard quadrants when king blooms were approximately 5% open. The participating grower applied the materials at label rates.
Bee Colonies. At the rate of one colony per acre, twenty bee hives, averaging 45,000 bees per colony, were moved in on the evening after spray applications were made. Colonies were placed in groups of four (as per commercial beekeeping procedures) equidistant through the center of the orchard. Foraging honey bee activity was evaluated by counting the number of bees visiting apple blossoms during a one minute walk around treated trees. Foraging bee counts were made in both morning and afternoon hours. All counts were made by the same observer.
Monitored Trees. In each quadrant, portions of ten designated trees, containing approximately 200 flower clusters, were tagged and counted at bloom and after fruit set was completed (mid-summer). The apple crop was estimated on a scale of: 1 = No Crop, 5 = Full Crop, and 10 = Excessive.
Results:
Honey Bee Foraging. Though there were significant differences in honey bee foragers during the 1998 season, the results were not duplicated in the 1999 season. The number of honey bees foraging on any of the treatments was not significantly different from the control trees (f=1.129). Forty observations of foraging bees were taken during the bloom cycle. The minimum number of foragers was 1 while the maximum number of foragers observed was 18. The number of honey bees observed foraging in 1999 was noticeably less than the number of forages observed in 1998. I am not sure why. The average number of bees on all trees was 8.5 while in 1998 the average number was 73.8 foragers per tree. The hive population was the same in both years. Both the weather and bloom population appeared good in 1999. Possible reasons for this discrepancy are innumerable. Sugar concentration of nectar, competing floral crops, protein (pollen) needs of colonies, and night-time temperatures, are possibilities.
Fruit Set and Crop. As expected from honey bee forager activities, there was no significant differences in fruit set. Fruit data is presented in Table 1.
Discussion. Fruit BoostTM is the only product having an attractive action mimicking the honey bee queen mandibular pheromone. The product is not commonly available in the Eastern US and Eastern Canada. In this study, the product showed promise in 1998, but positive observations were not duplicated in 1999. Both Bee ScentTM and Bee HereTM are products mimicking honey bee orientation pheromones. Previous studies conducted at The Ohio State University have indicated that Bee ScentTM performs best in light bloom seasons and is most attractive to foragers immediately after application (Tew and Ferree, 1999). That observation has not been duplicated in either 1998 nor 1999 in these studies. Common reasons, such as weather, tree health, orchard location, and competing floral sources could account for the difference in observations. Table 1. Influence of bee attractant products on fruit set and crop of Red Chief Delicious in a commercial orchard near Johnstown, Ohio in 1999.
* Bloom rating 1= no flowers to 10 snowball bloom, average 100 trees
Treatment Flower Clusters per limb Fruit/ Limb Avg. Fruit Set % Bloom Rating* Crop Rating** Check 335.6 Fruit Boost 324.5 Bee Scent 320.4 Bee Here 336.4
** Crop rating 1= no crop, 5=full crop, 10=excessive cropThis commercial orchard was selected because it has historically had a pollination problem. Pollinator trees are set out geometrically, but there still appears to be a problem with pollen transfer. Even in good fruit set years, this particular orchard has never produced a full crop. Though showing usefulness in some cases, other bee attractant study results on apple crops have been erratic. Since honey bee forgers are opportunistic when selecting floral sources and since most insect pollinator populations across the US are depressed, application of a dependable forger attractant would be beneficial to commercial growers.
The investigators would like to try one more season in order to develop some kind of statistical relevance, concerning bee attractants, when applied by growers in practical situations rather than research situations. We hope that future studies of this type will continue to delineate the types of products and methods of application that would concentrate honey bee forager activity on apple crops.
Literature Cited: Tew, James E. and David C. Ferree. 1999. The Influence of a Synthetic Foraging Attractant, Bee Scent, on the Number of Honey Bees Visiting Apple Blossoms and on Subsequent Fruit Production. Research Circular 299. pp. 14 – 23. The Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH 44691.
Companies Producing Attractants Used in this Study.
Bee HereTM
Troy Biosciences, Inc.
2620 N. 37th Drive
Phoenix, AZ 85009Fruit BoostTM
Phero Tech Inc.
7572 Progress Way
Delta, B.C. Canada V4G 1E9Bee ScentTM
Ecogen, Inc.
2005 Cabot Blvd. West
Langhorne, PA 19047-1810