Ohio State University Extension Bulletin

Fruit Crops: A Summary of Research 1998

Research Circular 299-99


The Influence of a Synthetic Foraging Attractant, Bee-ScentTM, on the Number of Honey Bees Visiting Apple Blossoms and on Subsequent Fruit Production

James E. Tew and David C. Ferree

Abstract

In three of the four years monitored, Bee-ScentTM influenced the number of honey bees foraging in treated apple orchards but did not seem to dependably increase the numbers of pollen-collecting foraging honey bees. Subsequent analysis of fruit quality and quantity was also positively influenced by Bee-ScentTM applications.

Introduction

Throughout the decade of the 1990s, honey-bee populations – both managed and feral – dropped precipitously because of chronic parasitism by newly introduced Varroa mites (Varroa jacobsoni) and Tracheal mites (Acarapis woodi). Pollination concerns have been express-ed both by beekeepers and fruit-and-vegetable growers as honey-bee populations have dwindled over the years.

As early as 1901, Sladen (8) described the function of the Nasonov gland (the scent gland) as one that functioned to produce chemicals that were attractive to other honey bees. Early pollinator attractants were essentially composed of scented sugared water. Rajotte and Fell (7), Burgett and Fisher (3), and Tew and Ferree (9) all reported that mixtures of scented sugar water were not effective in increasing fruit set on various crops. In 1965, Boch and Shearer (2) suggested that synthetic Nasonov gland secretions could possibly be used to attract bees to marginal crops. By 1987, Free et al. (4) reported that lures containing the synthetic components (E)- and (Z)-citrals, geraniol, nerolic, and geranic acids were effective in attracting honey-bee swarms and indicated that the attractant may have other uses. Bee-ScentTM is a commercially produced synthetic Nasonov pheromone. Mayer et al. (5) was able to show significant improvement in apple set after applying Bee-ScentTM.

A series of studies was conducted over a four-year period (1991, 1993, 1994, 1995) to determine the effectiveness of Bee-ScentTM, a commercially available honey-bee attractant, on foraging honey bees in two Ohio apple orchards. To compile data, various outdoor studies were implemented to monitor the activities of honey bees foraging on 'RedChief Delicious' apples after being treated with Bee-ScentTM. Also, within greenhouse conditions, honey-bee foraging studies were conducted on potted apple trees to test the effective attractive distance from treated trees and the persistence of Bee-ScentTM. Fruit set and size distribution were also monitored each year.

Materials and Methods

Outdoor Tests

All test sequences conducted outdoors had several criteria in common. Two orchards, approximately two miles apart, were used as needed in these studies. The first plot, located at The Ohio State University/Ohio Agricultural Research and Development Center (OARDC) Horticulture Unit 2, was a 3.2 acre block of 'RedChief Delicious' that was laid out north to south. At the beginning of the study (1991), the trees in Hort Unit 2 were seven years old and were set on MM.111 rootstock spaced 4.0 x 5.5 m. Tree pollenizers in Unit 2 were 'Golden Delicious,' 'Melrose,' and 'Rome Beauty.'

The second plot was located at OARDC's Snyder Farm and consisted of a four-acre plot planted in groups of four cultivars – 'Rome Beauty,' 'Golden Delicious,' 'McIntosh,' and 'RedChief Delicious' – and was laid out east to west. In both orchards, unsprayed test controls were always placed on the opposite end of the respective orchard from the tested trees. Both orchards allowed for approximately 300 feet separation between controls and treatments.

In all four test years, Bee-ScentTM was applied at 2 qts. per acre with an air-blast sprayer set to deliver 100 gal. per acre. Bee-ScentTM was applied when 10-20% of the king blooms were open. Fifteen trees were randomly selected in the sprayed and control areas; these trees were used in obtaining detailed measurements of bee behavior and fruit development.

In all outdoor test sequences, when king blooms were 10-20% open, bee hives were moved within 75 feet of the orchard. Three hives, averaging 35,000 bees per colony, having similar brood populations and similar food reserves, were positioned on either end of the respective test orchard. Therefore, six hives were used in each test at rates of nearly two colonies per acre (unless otherwise noted).

Beginning 24 hours later, depending on weather conditions, foraging bee counts were made during the day, at approximately two-hour intervals, until 1600 hours. Bee counts were made by counting foraging bees in the tree canopy during a one-minute period. Pollen foragers are better pollinators than nectar foragers. However, it is difficult to determine if a bee is a pollen collector if the foraging trip has only recently begun. Regardless, in all tests except 1995, when possible, pollen foragers were counted separately. The same person was responsible for taking all foraging estimates.

Portions of each of the 15 designated trees, containing approximately 200 flower clusters, were tagged and counted at bloom and later in the season when the final crop was harvested. All fruit from each tree were graded on an FMC weight size, and the number of fruit in each of the four size classes was determined. A sample of 10-25 apples from the box size 100-113 were measured for their length-diameter ratio. Fruit were cut and seeds counted.

Though similar in many respects, each of the four trials had some objectives unique to that particular study. These unique objectives are described here.

In 1991 and 1993, outdoor studies were conducted only in the Unit 2 orchard.

1993 Greenhouse Observations

On February 7 and March 8, 1993, dormant, potted apple trees were moved into a heated greenhouse to force blooming. During all subsequent tests, greenhouse ventilation systems were turned off. Three separate greenhouse apple pollination studies were set up and are discussed here.

Test 1 (March 6)
Five clusters on six control trees and five clusters on six treated trees were marked with plastic ribbon. While shielding all remaining parts of the trees, treatment clusters were sprayed with a hand sprayer, applying Bee-ScentTM at a dilution rate of 1.43 ml per 500 ml water (2 qts. per 150 gal.). Controls were shielded and sprayed with water. All trees were allowed to dry for one hour before being moved into a different greenhouse, where they were randomly positioned approximately 25 feet apart around the greenhouse. A double-story honey-bee hive, containing approximately 15,000 to 20,000 bees, approximately 40 square inches of open brood, and ample honey stores, was placed in the middle of the greenhouse on March 2, 1993. Experienced honey-bee foragers had been eliminated from the colony. Bee-forager activity was observed for six replications with each replication lasting 15 minutes.

Test 2 (March 8)
Four potted trees were completely sprayed with Bee-ScentTM while four other trees were sprayed with water to serve as controls. After a nine-minute observation (divided into three-minute intervals) was taken, trees were moved to the opposite side of the greenhouse to observe variations within foraging behavior caused by specific location in the greenhouse. The nine-minute count was subdivided into three-minute intervals to observe bee-forager dynamics.

Test 3 (March 29)
Four trees were completely sprayed with Bee-ScentTM (dilution rate 1.4 ml per 500 ml) once while four more trees were retreated daily. Four trees sprayed with water served as controls. Two sets of six clusters each were labeled and monitored for three days after applications. Treatment control trees were rotated after nine minutes to observe bee foraging behavior. Counts were taken at three-minute intervals within the nine-minute count to observe bee-forager dynamics. The same bee hive was used as in Test 1.

1994 Observations

The outdoor studies for this year followed the general methods discussed earlier but with one major change. Rather than only applying Bee-ScentTM once at king bloom, applications were made every other day until peak bloom. The Snyder Farm orchard was used. No greenhouse studies were conducted in 1994.

1995 Observations

The outdoor studies for this year followed the general methods discussed previously but with one major change. In light of the general reduction of the feral population of honey bees, observations were taken to determine if an application of Bee-ScentTM could positively affect fruit set when only 50% of a normal foraging honey-bee population was moved into an orchard (one-half colony per acre rather than the traditional one colony per acre). One-half colony per acre was supplied to the Snyder Farm orchard, while two full colonies per acre were supplied to the Unit 2 orchard. Though weather cannot be used as an excuse, it was a significant factor during the 1995 season. The blooming season was abnormally wet with orchards being constantly wet and muddy.

Results and Discussion

1991 Results

During the 1991 test period, 426 bees were counted on 262 treated trees for an average of 2.5 bees per tree (Table 1). On 165 control trees, 262 bees were observed, averaging 1.7 bees per tree. The difference between means of the total bees on trees was highly significant (P > 0.0004). Of the 426 bees foraging on treated trees, 297 (average 1.8 pollen foragers per tree) were pollen-collecting bees while 157 (average 1.0 pollen foragers per tree) of the 262 bees observed on control trees were pollen-collecting bees.

Table 1. The Influence of Bee-ScentTM on Honeybee Pollination and Subsequent Fruit Production When Applied Once to 'RedChief Delicious' Apple Trees in 1991.

  Honeybee Foraging Activityz Pollination and Fruit Productiony
Treatment

Bees/
Min/
Tree

Pollen-
Foragers/
Min/
Tree
Pollen-
Foragers
(%)
Fruit Set
(%)
Drops
(lbs/tree)
Picks
(lbs/tree)
Fruit Wt.
(g)
Fruit
Length/
Diameterx
Seed
Number/
Fruitx
Control
1.7 bw
1.0 b
59.9
57.5 b
17.6
57.1
154 a
0.85
5.40
Bee-ScentTM
2.5 a
1.8 a
69.7
75.4 a
22.2
47.5
135 b
0.85
6.08
z Foraging activity observed on April 26, 27, and 28, respectively.
y Pollination and fruit production data were obtained from a 15-tree subsample in control and treated plots. Approximately 200 flower clusters per tree were tagged on each tree at bloom for subsequent determination of yield per size data.
x Fruit shape and seed number were obtained from a sub-subsample of 10-25 fruit.
w Mean separation by the LSD statistic (P=0.05). Values within columns without letters are not significantly different.

The difference between pollen forager means was again significant (P > 0.0011). However, pollen foragers as a percent of total bees in each group was not significantly different. In the treated group, 69.7% were pollen foragers, while 59.9% of the bees in the control group were pollen foragers (P < 0.26).

Fruit set on test trees was significantly increased by nearly 18%, and fruit size with a greater fruit set was reduced by 13% (Table 1). However, because of the severe drought that began in late spring and continued through harvest, fruit size of all fruit was reduced and yields did not differ. The fruit shape or seed content was not influenced by Bee-ScentTM.

A correlation analysis revealed the expected significant relationships among the yield components – higher rates of fruit set were related to an increase in drops by weight (r = +0.57) and to increased numbers of seeds per fruit (r = +0.46) and decreased average fruit weight (r = -0.66); the weight of drops was also negatively correlated to the average fruit weight (r = -0.63). Perhaps the most interesting of these relationships was the relationship between number of seeds and difference in fruit set that resulted from the Bee-ScentTM application.

1993 Results

Greenhouse Tests
In general, greenhouse tests were inconclusive. Initially, honey bees foraged erratically. Since novice bees were used in the study, this was expected. However, once bees learned to work apple blossoms, numbers and intensity were so great that trends and effects were lost. Interestingly, honey bees were enticed to begin foraging only after a very high concentration of Bee-ScentTM (50% concentrate dilution) was applied to four trees. Bee attraction to blossoms was immediate. From that instant until the end of testing, forager activity on either controls or treated trees, in all tests, was intense. In Test 1, there was no difference between any of the tested treatment means, though there were some differences in bee activity on different days (Table 2, Figure 1A).

Table 2. The Influence of Bee-ScentTM on Honeybee Foraging Behavior When Applied Once to Open Flower Clusters of 'Golden Delicious' Apple (Greenhouse Test 1, 1993).

Factor No. Feeding Visits per 15 Min. No. Visits per 15 Min. Without Feeding
Treatment
   Control
78.9
6.5
   Bee-ScentTM
77.1
5.8
Persistence (days from spray)
   0
54.2 bz
7.1 a
   1
104.2 a
4.3 b
   2
75.5 b
7.0 a
z Mean separation by the LSD statistic (P=0.05). Values within columns within factors without letters are not significantly different.

Figure 1. A. Number of bee visits per 15 minutes per tree day to Bee-Scent-treated 
        and control 'Golden Delicious' trees (Greenhouse Test 1, 1993)
Figure 1. B. Number of bee visits per minute per tree per day to Bee-Scent-treated 
        and control 'RedChief Delicious' trees (Orchard Test, 1993).
Figure 1. C. Number of pollen-foraging bee visits per minutes per tree per 
	day to Bee-Scent-treated and control 'RedChief Delicious' trees (Orchard Test, 1993).
Figure 1. A. Number of bee visits per 15 minutes per tree day to Bee-ScentTM-treated and control 'Golden Delicious' trees (Greenhouse Test 1, 1993). B. Number of bee visits per minute per tree per day to Bee-ScentTM-treated and control 'RedChief Delicious' trees (Orchard Test, 1993). C. Number of pollen-foraging bee visits per minutes per tree per day to Bee-ScentTM -treated and control 'RedChief Delicious' trees (Orchard Test, 1993).

 

In Test 2, there appeared to be no difference in location within the greenhouse or in attractiveness throughout the three-day test period. Results from Test 3 (Table 3) are also inconclusive. Bee-ScentTM applied only once each day (three days total) attracted no more bees than the controls. There was a delay in foragers finding blossoms, but that was expected.

Table 3. The Influence of Bee-ScentTM on Honeybee Foraging Behavior When Applied Once or on Three Successive Days to 'Golden Delicious' Apple Trees (Greenhouse Test 3, 1993).

  Bee Foraging Activity per 3-Minute Period
Treatment Period 1 Period 2 Period 3
Control
48.5
140.5
79.5
Bee-ScentTM Applied Once
54.2
152.2
157.5
Bee-ScentTM Applied 3X
45.2
158.7
78.0

Orchard Tests
Overall, treated trees averaged 5.5 bees per tree, which was significantly different from control trees, which averaged 4.1 bees per tree (Table 4). When evaluated on a daily basis, mean foraging observations were different on the first day (May 7, 1993) but not the following two days (Figure 1B). Trees treated with Bee-ScentTM averaged 7.6 bees per tree while control trees averaged 4.9 bees per tree on May 7. Also, pollen collectors were present in greater numbers on treated trees (3.5 foragers per tree) than on control trees (2.5 bees per tree) (Figure 1C). Again when evaluated on a daily basis, on the first day (May 7), mean pollen foragers on treated trees (4.9 foragers per tree) differed from the mean pollen foragers on control trees (3.1 foragers per tree) while means from the remaining two days were not different (Table 4). Pollen foragers as a percent of total bees in each group was not significantly different (57.3% treatment, 56.5% control).

Table 4. The Influence of Bee-ScentTM on Honeybee Foraging Behavior and Subsequent Fruit Production When Applied Once to 'RedChief Delicious' Apple Trees in 1993.

  Honeybee Foraging Activityz Pollination and Fruit Productiony
Treatment

Bees/
Min/
Tree

Pollen-
Foragers/
Min/
Tree
Pollen-
Foragers
(%)
Yields
(lbs/
tree)
Fruit
Set
(%)
No.
Fruit/
Tree
Fruit
Wt.
(g)
Fruit
Length/
Diameterx
Viable
Seeds/
Fruitx
Shriveled
Seeds/
Fruitx
Control
4.1 bw
2.5 b
56.5
104.8 b
67.2
690 b
99.8 b
0.96 a
6.4
0.5 b
Bee-ScentTM
5.5 a
3.5 a
57.3
150.5 a
72.5
818 a
110.8 a
0.92 b
6.4
1.1 a
z Foraging activity observed on May 7, 8 and 9, respectively.
y Pollination and fruit production data were obtained from a 15-tree subsample in control and treated plots. Approximately 200 flower clusters per tree were tagged on each tree at bloom for subsequent determination of yield per size data.
x Fruit shape and seed number were obtained from a sub-subsample of 10-25 fruit.
w Mean separation by the LSD statistic (P=0.05). Values within columns without letters are not significantly different.

Fruit Set and Distribution
Spray of Bee-ScentTM increased yield per tree, average fruit weight, and number of shriveled seeds (Table 4). Fruit from treated trees were less elongated. Fruit size was increased, and the percentage culled mostly for inadequate size was decreased by 50%, resulting in nearly doubling the value of fruit from treated trees (Table 5). Commercial growers also experienced extremely small fruit size in 1993 because of a combination of weather factors that resulted in inadequate chemical thinning and over-cropping. It is interesting here that even though yield was increased, salable apples were also due to increased size. This was likely caused by the increased seed numbers early in the season during the cell-division period.

Table 5. The Influence of Bee-ScentTM Applied Once During Flowering on Fruit Size Distribution of 'RedChief Delicious' Apple at Harvest in 1993.

  Weight (lbs per tree) Weight (% of total yield)  
  Fruit Diameter Range (mm) Fruit Diameter Range (mm)  
Treatment >80 80-73 73-57 Cull >80 80-73 73-57 Cull Value ($)
Control
0.1
0.5 bz
30.5 b
73.7 a
0.1
0.4 b
28.5 b
70.9 a
7.57 b
Bee-ScentTM
0.2
11.5 a
92.6 a
46.2 b
0.1
7.1 a
60.8 a
31.9 b
15.79 a
z Mean separation by the LSD statistic (P=0.05). Values within columns within factors without letters are not significantly different.

1994 Results

Orchard Tests
Multiple applications of Bee-ScentTM appeared to have minimal effect on increasing honey-bee pollinator activity when compared to single applications (as per label instructions). Though the trend shown by the data tended to support multiple applications, the differences were not significant. In the Snyder Orchard, 13.9 bees were observed foraging on untreated trees while 18.4 bees were observed foraging on treated trees. Within the Unit 2 orchard, 40.6 bees were observed forging on untreated trees while 59.5 bees were observed on treated trees (Figure 2A). However, there was a difference when data from both orchards were combined and analyzed. Combined treated means of 36.2 foraging bees per tree were different (P > 0.0054) from combined untreated means of 23.8 bees per tree (Table 6). In all aspects of this study, numbers of pollen-collecting bees appeared to be statistically unaffected by Bee-ScentTM applications though there was again a trend in favor of treated trees. Combined data from both orchards yielded means of 15.7 pollen-collecting bees per untreated tree while treated means of pollen-collecting bees was 23.2 per tree (Figure 2B).

Number of bee visits per minute per tree per day to Bee-Scent-treated and control trees. Number of nectar and pollen-foraging bee visits per minute per tree Bee-Scent-treated and control trees.
Figure 2. A: Number of bee visits per minute per tree per day to Bee-ScentTM-treated and control trees. B: Number of nectar and pollen-foraging bee visits per minute per tree per day to Bee-ScentTM-treated and control trees (all cultivars, Orchard Test at both sites combined, 1994).

Table 6. The Influence of Bee-ScentTM on Fruit Set, Fruit Weight, Seed Number, and Seed Viability After Multiple Applications to 'RedChief Delicious' and 'Golden Delicious' Trees During Flowering in 1994.

Location Cultivar Treatment Fruit
Set
(%)
Fruit
Wt.
(g)
Fruit
Shape
(L/D)
Seeds/
Fruit
Viable
Seeds/
Fruit
Shriveled
Seeds/
Fruit
Hort Unit 2z RedChief Delicious Control
97
154 ay
0.92
5.7 b
6.1
0.2
    Bee-ScentTM
100
135 b
0.89
6.6 a
6.1
0.5
Snyder Farmx RedChief Delicious Control
87
145
0.85
6.0 b
n.d.
n.d.
    Bee-ScentTM
86
124
0.90
8.1 a
n.d.
n.d.
Snyder Farmx RedChief Delicious Control
77
163
0.84 b
6.5 b
n.d.
n.d.
    Bee-ScentTM
100
104
0.90 a
8.1 a
n.d.
n.d.
z Bee-ScentTM sprays applied by airblast sprayer on May 2 (when 10-15% of the flowers were open) and again on May 11 due to a long bloom period.
y Mean separation by the LSD statistic (P=0.05). Within columns, values for specific cultivars per location combinations without letters are not significantly different.
x Bee-ScentTM sprays applied by airblast sprayer at two-day intervals beginning May 2 for a total of five applications.

 

Fruit Set and Distribution
Applications of Bee-ScentTM at bloom to 'RedChief' and 'Smoothee Golden Delicious' had no effect on the percent of fruit set or fruit size (Table 6). Fruit size of Golden Delicious was reduced and, although the 24% increase in set was not significant statistically, the increase in crop was likely responsible for the reduction in size. Production in 1994 was very light in this plot (and over the eastern portion of the United States) due to the heavy crop in 1993 and drought conditions that resulted in reduced flower initiation.

Bee-ScentTM did improve the shape and seed content of both 'Delicious' and 'Golden Delicious' in this study at the Snyder Farm. In the study at Unit 2, 'RedChief Delicious' fruit set or shape was not influenced by applications of Bee-ScentTM (Table 6). Fruit weight was reduced and seed content increased. Fruit from these trees were harvested and graded. Bee-ScentTM treated trees tended to have smaller fruit-size distribution than untreated trees (Table 6). Since yield was not different between the treated and untreated trees, the authors have no explanation for this difference.

1995 Results

Orchard Tests
During the 1995 season, Bee-ScentTM seemed to have no influence on bee forager populations when compared to controls (Figure 3). Hort Unit 2 averaged 43.6 foragers per tree, while control trees had a mean population of 42.4 bees per tree. The means were not different (P < 0.65). Though forager populations were smaller at the Snyder Farm orchard, as was expected, statistical results were similar. Snyder Farm treatment trees averaged 16.2 bees per tree while controls averaged 15.8 bees per tree (P < 0.92). When data was combined for both test orchards, significance did not increase. The combined means for treated trees was 29.9 while the combined means of untreated controls was 29.11. The combined means were not different (P < 0.75).

 Number of bee visits per minutes per tree per day to Bee-Scent
Figure 3. Number of bee visits per minutes per tree per day to Bee-ScentTM-treated and control trees (all cultivars, Orchard Tests at Hort Unit 2 and Snyder Farm, 1995).

Due to the sizable difference in honey-bee populations, means between orchards were different. The mean number of foragers at Unit 2 (43.6 foragers) on treated trees was significantly greater than the mean number of bees on treated trees at the Snyder Farm (16.2 foragers) (P > 0.022). Controls were also significantly different. Unit 2 forager-bee populations averaged 42.4, while control populations at the Snyder Farm averaged 15.8 foragers (P > 0.018). Though Bee-ScentTM played no role, the significant difference between orchards supports the established concept that foragers from supplemental bee colonies (rented bee colonies) do tend to stay within the orchard to which they are moved. Also, during the 1995 season, continual heavy rains were a major factor.

Fruit Set and Size Distribution
In 1995, application of Bee-ScentTM increased the amounts of large- and medium-size fruit and decreased the amount of small fruit without changing the total yield of 'RedChief Delicious' (Table 7). Fruit set of 'RedChief Delicious' was significantly increased at Unit 2 (control 32% and Bee-ScentTM 52%) with a similar but nonsignificant trend at Snyder Farm (control 31%, Bee-ScentTM 37%).

Table 7. The Influence of Bee-ScentTM Applied Once During Flowering on Yield and Fruit Size Distribution of 'RedChief Delicious' Apple at Harvest in 1995.

  Weight (lbs/tree) Weight (% of total yield)  
  Fruit Diameter Range (mm) Fruit Diameter Range (mm)  
Treatment No.
Fruit/
Tree
Yield
(lbs/
tree)
>80 80-73 73-57 Cull >80 80-73 73-57 Cull Value ($)
Control
594
141.8
0.5 bz
7.8 b
99.1 a
34.0
0.6
7.0 b
69.0 a
23.3
12.90
Bee-ScentTM
587
155.1
3.0 a
42.2 a
74.4 b
35.3
2.3
28.5 a
46.9 b
22.2
14.64
z Mean separation by the LSD statistic (P=0.05). Values within columns within factors without letters are not significantly different.

 

Conclusions

Overall, Bee-ScentTM was effective in attracting more honey bees to treated orchards. This conclusion is supported by the results of studies performed by Mayer et al. (5) in Washington. His results showed a significant increase in bee activity in treated areas and in subsequent fruit set. However, Morse (6) said that Bee-ScentTM had not been effective on New York apples. Additionally, studies on other crops have yielded variable results. Ambrose et al. (1) found that Bee-ScentTM had no effect on improving set in cucumbers or watermelons.

Though application techniques varied during each test year, Bee-ScentTM was applied at the same period of bloom development in all four years and was compared with untreated trees. In 1991, 1993, and 1994, Bee-ScentTM increased the number of honey-bee foragers on apple blossoms significantly. Though weather is commonly a factor in all outdoor studies, the spring of 1995 was particularly wet and could readily justify the lack of success by Bee-ScentTM that year.

Whereas a trend did emerge toward increased pollen foragers, the data did not clearly show that Bee-ScentTM was effective in attracting more pollen foragers. During the 1991 and 1993 studies, there was a significant difference in the number of pollen foragers, but it could not be shown in 1994. Though the number of pollen gatherers may not always be increased, from the overall data collected it seems apparent that Bee-ScentTM is effective in attracting increased numbers of honey-bee foragers to treated orchards.

Greenhouse studies were unhelpful in determining persistence of Bee-ScentTM residue or of effective Bee-ScentTM bouquet area. This information would have been useful in increased understanding of the characteristics of Bee-ScentTM in outdoor orchard conditions. These questions still need to be studied.

The effects of Bee-ScentTM on fruit set and size distribution varied with season. In years with light crops and ample fruit size (1991 and 1994), there were no beneficial effects. However, in years where commercial growers faced significant problems of small fruit set (1993) or poor set (1995), applications provided significant advantages of improved fruit size and, in 1995, both improved set and fruit size. Fruit set tended to be improved on at least one cultivar in three of the four years the authors correlated tests. The results generally were associated with increased bee foraging.

Since positive benefits occurred in some years, growers may want to consider use of a synthetic bee pheromone attractant in years when problem conditions for pollination and fruit set are threatening. The reduction in feral bees means that growers will need to do everything possible to ensure pollination, including such cultural practices as having ample and strategically located cultivars, decreasing competing flowering plants such as dandelions, and bringing in sufficient strong colonies of bees.

Acknowledgments

Scentry, 2005 Cabot Blvd., West Langhorne, PA 19047.

Literature Cited

  1. Ambrose, John T., J. R. Schultheis, S. B. Bambara, and W. Mangum. 1995. An evaluation of selected commercial bee attractants in the pollination of cucumbers and watermelons. Amer. Bee J. 135:267-272.
  2. Boch, R. and D. A. Shearer. 1965. Attracting honey bees to crops which require pollination. Amer. Bee J. 105:166-167.
  3. Burgett, M. and G. C. Fisher. 1979. An evaluation of Beeline as a pollinator attractant on red clover. Amer. Bee J. 119:356-357.
  4. Free, J. B. 1987. Pheromones of social bees. Comstock Publ. Assoc., Ithaca, New York.
  5. Mayer, D. F., L. Britt, and J. D. Lunden. 1989. Evaluation of Bee-ScentTM as a honey-bee attractant. Amer. Bee J. 129:41-42.
  6. Morse, R. A. 1992. Professor, Cornell University, Personal Communication.
  7. Rajotte, E. G. and R. D. Fell. 1982. A commercial bee attractant ineffective in enhancing apple pollination. HortScience 17:230-231.
  8. Sladen, F. S. L. 1989. The humble bee. Langaston Press, London. Reprint of 1915 edition.
  9. Tew, James E. and David C. Ferree. 1984. The effect of Bee Lure on honey bee (Apis mellifera) pollination of apples. Fruit Crops 1984: A Summary of Research. The Ohio State University. Ohio Agricultural Research and Development Center. Special Circular 283. pp. 31-32


Back | Forward | Table of Contents