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Bee pollination benefits for rockmelon crops

Extract from Bulletin 4298: Honeybee pollination

Rockmelon (honey dew, muskmelon, cantaloupe)

Cucumis melo var reticulatus (Rockmelon)
Cucumis melo var inodorus (Honey Dew)

Flowers

Most rockmelons have male (staminate) flowers that are borne on different branches to hermaphroditic flowers (bisexual flowers), which are also produced (that is, the plants are monoecious). (On watermelons, male and female flowers are on the same branch). This type of flower arrangement is also known as andromonoecious. Insect pollination is necessary where the sexes are in separate flowers; and hermaphrodite flowers that are insect pollinated have a higher rate of successful self-pollination. Flowers are open for one day, male flowers appearing first. There are usually 10 male flowers to every hermaphrodite flower (see Ref. 15).

Each seed is formed from the union of a single pollen grain and a single ovule. Misshapen and undersized fruit are often caused by inadequate pollination, that is, low numbers of fertilised seed. Generally, melons that contain fewer than 400 seeds will not be marketable. Culled fruit in New Zealand averaged 416 seeds and weighed 1.15 kg, their minimum export size was 900 g with a minimum of 380 to 400 mature seeds. Melons produced near the crown are often sweeter, larger and better shaped and bring better prices.

Mutant nectarless rockmelons were being planted in USA in the 1960s, honey bees ignored these crops and as a consequence yields were poor from fruit abortion, development of small and misshapen fruit. To overcome these problems, normal nectar producing rockmelon varieties were mixed in with these crops and yields returned to normal (Ref. 9). Different rockmelon varieties can produce different quality nectars in various quantities to which honey bees will respond accordingly.

Honey bee pollination is essential for PROFITABLE production. (see also Watermelons for further research notes).

Rockmelon	Ref. 14	Texas (USA)	Broome (WA)	Kununurra (WA)
Days from planting to harvest	85 to 110	95 to 106	69 to 87	61 to 85
Days from pollination to market maturity	42 to 46
Days from planting to first female flower				22 to 40

Nectar

Sugar in the nectar ranged from 27% to 36% in hermaphroditic flowers and 53% to 56% in staminate flowers. Nectar production ranged from 1.2 to 2.7 mg/staminate flower and 1.8 to 17.9 mg/hermaphrodite flower with the majority of the nectar being produced in the afternoon. Nectar production/ha over 20 days increased from 0.3 kg/ha to 1.91 kg/ha as the vines grew and the number of flowers increased five-fold from 10 769 to 53 797 flowers/ha (Ref. 15).

In New Zealand, hermaphrodite flowers contained more nectar (2.25 µL) than male flowers (0.92 µL). Sugar concentration ranged from 25 to 33%.

In Africa, hermaphrodite flowers contained more nectar (12.1 µL) than male flowers (4.3 µL). Sugar concentration ranged from 24 to 32%, being higher in male flowers. Hermaphrodite and male flowers produced 3.09 and 1.58 mg of nectar sugar/flower respectively (Ref. 6).

Pollen

The pollen grains are too sticky and heavy to be carried by wind. Flowers open and release their pollen when the humidity is low and equally well during rainy weather. Successful fruit production requires the transfer of 500 to 1 000 viable pollen grains to the stigma.

Minimum temperature for anthesis and anther dehiscence in rockmelons is 18.3°C. Both reach an optimum between 20°C and 21.1°C (Ref. 16). In the Honeydew, anthesis does not occur below temperatures of 20°C, but dehiscence may occur at 18.3°C, with the optimum for both anthesis and dehiscence being between 21.1°C and 23.9°C.

The number of pollen grains present on stigmas exposed to insect activity for the whole day ranged from 640 to 9 570 grains per stigma. Foraging honey bees exiting hermaphrodite flowers carried up to 2 500 pollen grains on their body. Average pollen production of staminate and hermaphrodite flowers is estimated at 11 500 pollen grains/flower (Ref. 6).

Hives per hectare

Pollination can be delayed at least one week from the first female flowering without negatively affecting productivity or harvest time (Ref. 5). Fertilisation and fruit set were as good when plants were covered with a plastic tunnel for 20 days then removed for pollination compared to plants uncovered to permit open pollination (Ref. 6). This can allow growers additional time to apply insecticides (should they be needed) and reduce honey bee exposure to insecticides. The delay in introducing bees to plastic tunnels seems to have also reduced the incidence of vitriscence (glassiness) in melons (Ref. 1).

• One bee per ten flowers - hives no greater than 100 m from each other; 7.5 hives/ha (USA);
• 0.3 to 0.5 (USSR);
• 25 to 75 hives/10 ha (Queensland);
• 3 hives/ha; 4 to 8 hives every 300 m in larger crops (more than 13 ha) - New South Wales (Ref. 10).

Supplementary feeding of hives whilst in crops/experiments

Sugar syrup has been fed to hives (Ref. 7) with access to water - because of the poor source of carbohydrate from the crop. Protein cakes have been used in 5-frame nucleus hives in air-inflated greenhouses where consumption was 225 g/week. Honey bee activity was enhanced by their use (Ref. 12).

Bees obtain little nectar from flowers, and strong hives become lazy and do not pollinate as well as smaller hives. Continually observe fruit set and adjust the number of hives in the field. Move beehives into crop when 6% to 7% of the crop is in flower (Argentina).

Honey bee foraging

Honey bees visited flowers for an average 20 to 34 visits/flower/hour using 2.5 hives/ha (Ref. 13). With feral bees present there is about 1 bee/500 flowers, with less than 2.5 hives/ha employed there is 1 bee/333 flowers and in an experiment where an average of 9.1 bees/flower gave marketable fruit, the bee to flower ratio was 1 bee/110 flowers (Ref. 8).

71% of flower visits by honey bees occurred before midday. Foraging activity of flowers under plastic tunnels was on average 2.67 bees/100 flowers, in open fields it was 2.58 bees/100 flowers (Ref. 6). In greenhouses, bee visits were 10 to 12 bees/100 flowers (Ref. 12).

Rockmelon

Average honey bee visits	Flower development following honey bee visit
6.3	74% of flowers aborted
8.2	Flowers set but a large number of fruit were culls.
9.1	Marketable melons produced
Less than 8	34.7% developed into marketable fruit
More than 8	54.3% developed into marketable fruit
13 to 14	No significant benefit over having 9.1 bees/flower.

After McGregor et al. (1965). Note: A 19.6% difference between having less than 8 or more than 8 bees per flower. Culls were fruit weighing less than 680 g.

In a rockmelon crop, 47% of European honey bee foragers were found within 50 m of the apiary, for Africanised bees, 71% of foragers were found within 50 m of their nest. Pollen collecting honey bees foraged at greater distances than nectar collecting bees (Ref. 2).

Effect of row planting

Bees were observed to visit consecutive plants along a row more frequently than across rows (Ref. 15).

Pollination fee

• $20/hive/shift for a pollination period of three weeks (1986 - Western Australia).
• $20/hive/shift plus $1.00/day/hive while pollinating (1986 - WA).
• $25/hive/0.41 ha (1987 - New South Wales).
• $30/hive (1989); $50/hive (1999) -WA).

Cost benefit for growers of a pollination service

CASE 1: In 1994 the $90 per hectare pollination fee for rockmelons represented about 20 per cent of pre-harvest production costs.

CASE 2: Financial gain to the rockmelon grower in NSW was calculated per case of fruit following honeybee pollination. The initial pollination fee of 4 to 6 cents per case gave the grower a return of between 50 cents and $3 per case (Ref. 10).

Honey production

26 to 50 kg honey per hectare and small amounts of pollen are also gathered.

Melons in glasshouses

In Japan, melons are grown in glasshouses with controlled temperatures of 30°C during the day and 22°C at night. A variety 'Red Arus' can only be grown in a glasshouse and is pollinated by placing beehives just outside the entrance (New Zealand).

Colonies were placed at the end of glasshouse (France). In the first crop, four out of six plots (each of 80 plants) gave 75 per cent or more of their production in a harvesting period of 5 to 6 days.

Carbon dioxide levels in glasshouses are sometimes elevated to increase soluble solids (sweetness) in the melons. In an experiment where CO₂ levels were increased from 200 ppm to 600 ppm there was no effect on overall bee activity (Ref. 12).

Melons under polypropylene covers

Polypropylene covers are used to stimulate plant growth and promote early crop yields.

Rockmelon (Canada) cv Earlisweet
After Gaye et al. (1991).

		No cover	Covered: no bees	Covered: with bees*
Weight of fruit (g)		770	718	863
Seed number			582	448
Weight of seed (g)			0.0146	0.0266
Total marketable yield (t/ha)		37.5	35.8	63.5
Undersize melons (t/ha)		5	14.5	3.4
Approx. days (d) from harvesting (day 0)		18 d longer	9 d longer	Day 0

*single 9 frame box of bees used fed with sugar syrup

In Israel, rockmelons are grown under 120 m long x 2.2 m high x 4.8 m wide 'walk-through' plastic tunnels in winter in Arava Valley desert. The plastic tunnels are orientated north to south to prevent the tunnels from being blown away by strong southerly winds. Honey bee hives were best located at the northern end so the bees had to fly against the wind - which was 64% of the time came from the south between 9 am to 11 am. Fruit set was highest in the northern end of plastic tunnels than in tunnels with beehives placed at their southern end (Ref. 4).

Beehives were picked up during the day to 'bleed' off all the field bees before being placed into plastic tunnels. Pollination effectiveness of individual honey bees were greater under plastic covers than in the open field (Ref. 6).

Rockmelon (Greenhouse)
After Iselin et al. (1974)

	Open to bees first 21 days then covered	Covered, no bees	5 frame nucleus hive	Covered first 21 days, then open to bees
No. of melons	4.2	0.36	3.73	3.70
No. of seeds	505	0	524	544
Melon weight (g)	1480	--	1549	1629

Rockmelons sealed in polyethylene tunnels with a single beehive produced 0.97 kg export quality fruits/plant. Polyethylene tunnels with one open end produced 0.56 kg export quality fruits/plant (Ref. 3).

Review of bee pollination benefits

Individual fruit weight was greater from row cover (spun-bonded polypropylene) treatments with bees than without, and was highly correlated with total seed weight. The increase in yield was 69.3% (Canada - Ref. 7).

Fruit set and marketability of rockmelons was correlated with visits by honey bees (Apis mellifera) up to 13 to 14 bees/flower (Ref. 8).

Increasing the number of honey bee visits significantly increased the likelihood that flowers would set (r=0.82) and also increased the chance that the melon would be marketable (r=0.57) (Ref. 8).

Increase in crop production was 58.2% higher (Ref. 17).

Rockmelon (Arizona, USA)
After Taylor (1955)

	Replicates	Number of melons/plant
Fields (no bees visible)	17	0.67
Fields (beehives within 1.6 km)	20	1.06

Increase in average rockmelon weight by 40 per cent in New South Wales. (Ref. 10).

Increase in the number of rockmelons by 25 per cent in New South Wales. (Ref. 10).

Rockmelon
After Williams (1987)

	No bees in cage	Bees in cage
Average total weight in 6m2 (kg)	13.4	28.5
Average fruit weight (kg)	0.68	1.11
Average total number	20	26

Seventeen crops with no bees in vicinity produced 0.67 melons per plant whilst 20 crops with an average of 0.2 hives per hectare within 1.6 km averaged 1.06 melons per plant in USA (Ref. 17).

Crops require up to 14 bee visits per flower for marketable melons in USA (Ref. 8).

In a greenhouse, honey bees flew to and pollinated rockmelons satisfactorily (Ref. 11).

Rockmelon (Greenhouse)
(After Lemasson, M. (1987) Revue de l'Agriculture 40 (4): 915-924)

	Honey bees	No honey bees
% Fruit set	18.5	2.5
Fruit weight/plant (g)	2 664	1 469
Average fruit weight (g)	621	491
Average no. of fruits	4.3	2.9

Rockmelon (Arizona, USA)
After McGregor and Todd (1952) - data are averaged

	10 frame single hive in 18.6m2 cage	No bees in cage	Hive caged after crown flowers had withered	Open field (1 hive/5.7ha)
No. of marketable melons	180	4	184	145
No of seeds per melon	552	78 (small) 387 (edible)	586	469
No of culls	94	27	136	95
% of undersize melons	53	96	56	65

Abstracts of scientific papers on rockmelon pollination

1. Melon: pollination and vitriscence
2. Comparative foraging distances of Africanized, European and hybrid honey bees during pollination of cantaloupe
3. Integrated production of out-of-season cantaloupes in West Africa, with the aid of a spunbonded row cover
4. The influence of hive location on honeybee foraging activity and fruit set in melons grown in plastic greenhouses
5. The effect of delaying pollination on cantaloupe production
6. Pollination of cantaloupes under spunbonded row cover by honey bees in West Africa
7. Honey bees placed under row covers affect muskmelon yield and quality
8. Honey bee visitors and fruit set of cantaloupes
9. Insect pollination is necessary for the production of muskmelons
10. Pollination of melons
11. Pollination of melons in greenhouses
12. The pollination of melons in air inflated greenhouses by honey bees
13. Honey bee visit numbers and watermelon pollination
14. Cucurbits
15. Cantaloup production with honey bees
16. The influence of climatological factors on anthesis and anther dehiscence in the cultivated cucurbits. A preliminary report.
17. Cantaloup production increased with honey bees

1. TITLE: Melon: pollination and vitriscence
   ABSTRACT: The incidence of vitrescence (glassiness) in melons grown in plastic tunnels, using honey bees as pollinators, was recorded. It occurred mainly on fruits ready at the beginning of the harvest: 86% of all vitrescent melons at two sites were collected during the first 12 days. In tunnels where the introduction of bees was delayed by up to 9 days after the start of flowering, the incidence of vitrescence was lower but the total weight and fruits/plant were not affected. The fruits were ready for harvest only a few days (up to 5) after fruits on control plants.
   AUTHOR: O. Prothais, B. Navez, A. Derveau, B. Vaisseère
   JOURNAL: Infos (Paris) No. 81, 2, 33-36 (1992).

2. TITLE: Comparative foraging distances of Africanized, European and hybrid honey bees (Apis mellifera L.) during pollination of cantaloupe (Cucumis melo L.).
   ABSTRACT: Foraging distances were compared for Africanized, European and hybrid honey bee colonies used for commercial pollination of cantaloupe in Costa Rica. Randomly chosen foragers (n - 2398) were identified by tagging with ferrous discs at sampling stations location 0 £ 50, 250, 550 and 800 m from study colonies. Tags (727) were recovered by magnetic traps at hive entrances. Africanized colonies consistently foraged closer to their nest (71% of Africanized bees compared with an average of 47% of European and hybrid bees were tagged at £ 50 m). Differences in foraging distances between bee types were greater for pollen foragers than for nectar foragers. European and hybrid bees had similar foraging distances. Pollen collectors foraged at greater distances than nectar collectors. The relatively shorter foraging distances of Africanized honey bees may require that, for effective pollination, colonies be distributed more uniformly and closer to target crops with less distance between apiaries.
   AUTHOR: R.G. Danka, J.D. Villa and N.E. Gary
   JOURNAL: Bee Science 3(1): 16-21 (1993).
   
3. TITLE: Integrated production of out-of-season cantaloupes in West Africa, with the aid of a spunbonded row cover
   ABSTRACT: In this region, Cucumis melo is subjected to severe attacks by insects. Trials were made in Senegal with plants:
   
   1. in sealed polyethylene tunnels,
   2. as A but with one end open,
   3. as A but supplied with honey bees (Apis mellifera adansonii) by fitting the tunnel with three entrances from a hive,
   4. polyethylene laid directly on the plants.
   Best results were obtained from C plants, which yielded 0.97 kg export-grade fruits/plant. B plants gave 0.56 kg/plant. Methods A and D were not economically viable.
   AUTHOR: R. Froissart, M. Gerard, B.E. Vaissière
   JOURNAL: Fruits (Paris) 50(5): 359-374 (1995).
   
4. TITLE: The influence of hive location on honeybee foraging activity and fruit set in melons grown in plastic greenhouses
   ABSTRACT: Melon (Cucumis melo L) is a very important winter crop in Israel, especially in the extremely hot Arava Valley. The melons are grown in 120 metre long plastic tunnels, which create problems in terms of pollination. Because of local southern windstorms, the long plastic tunnels can only be oriented in one direction, from north to south. Beekeepers disagree as to the best site to locate the bee hives. Observation of bee foraging behaviour and analysis of wind direction in the experimental plots revealed that placing hives at the northern end of the tunnel allows for higher bee activity in the morning. This results in a higher yield compared with that obtained when hives are located at the southern end of the tunnel.
   AUTHOR: A. Dag, D. Eisikowitch
   JOURNAL: Apidologie (1995) 26: 511-519
   
5. TITLE: The effect of delaying pollination on cantaloupe production
   ABSTRACT: During the growing seasons of 1992 and 1993, in Weslaco, Texas, USA, pollination of cantaloupes (Cucumis melo) was delayed by either 0, 6 or 12 days. Pollination was prevented by covering plants with floating row covers at the time of first female flowering. Plants were left covered for either 6 or 12 days and then exposed to honey bee visitation. Cultivars used in the 1992 season were Cruiser, Explorer and Primo. Cruiser, Mission and Primo were used in 1993. Twelve colonies of honey bees were placed on the border of the test plots in 1992 and two in 1993. In 1992, Primo plants which had pollination delayed for six days produced heavier fruits and a greater total fruit weight per plant than those not delayed or delayed 12 days. Cruiser and Explorer produced smaller fruits when pollination was delayed 12 days but were unaffected by a 6 day delay. In 1993, Mission delayed for 12 days produced more fruits per plant. No differences in fruit quality (percentage culls, soluble solid content and size) or number were observed in other cultivars when pollination was delayed. In both trials, the median harvest time was about the same as controls when pollination was delayed for six days. These results suggest that the time honey bee colonies need to be in the field for cantaloupe pollination could be reduced. Pollination could be delayed by about one week without negatively affecting productivity or harvest time. This would provide growers additional time in which to apply insecticides should they be needed, and reduce honey bee exposure to insecticides.
   AUTHOR: Fran A. Eischen, Benjamin A. Underwood, Anita M. Collins
   JOURNAL: Journal of Apicultural Research 33(3): 180-184 (1994).
   
6. TITLE: Pollination of cantaloupes under spunbonded row cover by honey bees (Hymenoptera: Apidae) in West Africa
   ABSTRACT: We evaluated two pollination treatments that did not require removal of the cover on cantaloupes under small tunnels of Agryl in West Africa. The cover was removed from control plots at the onset of pistillate flowering but was maintained over treated plants for an additional 20 days. In the first treatment, one end of the tunnel was cut open to allow some access to pollinators. In the second treatment, the tunnel was kept closed but was provided with a multiple-entrance hive.
   The cover did not affect production or concentration of nectar. Honey bees, Apis mellifera adansonii Latreille, flew under the cover in both treatments, with an average of 54% as many bees foraging under the tunnels opened at one end as in the control, However, muscid flies, which were the most abundant flower visitors in the open, hardly foraged under the cover. Pollination intensity and amount of cantaloupe pollen on the body of honey bee foragers in the two covered treatments were similar but were significantly greater than in the open. Total yield, fruit size, and seed content confirmed that pollination was at least as good in the covered plots as in the control. Covered plants produced more commercial-grade fruit than control plants, which received six insecticide applications, demonstrating the usefulness of these pollination treatments in combination with the row cover for integrated pest management.
   AUTHOR: Bernard E. Vaissière and Rémy Froissart
   JOURNAL: Journal of Economic Entomology 89(5): 1213-1222 (1996).
   
7. TITLE: Honey bees placed under row covers affect muskmelon yield and quality
   ABSTRACT: Row covers, removed at the first flush of female flowers, advanced the initial harvest date, enhanced early yield and improved fruit quality of two cultivars of muskmelon (Cucumis melo L.). Including colonies of bees (Apis mellifera L.) under the covers enabled the covers to be left on for another month and further advanced the initial harvest date and early yield. Individual fruit weight was greater from row cover treatments with bees than without, and was highly correlated with total seed weight.
   AUTHOR: M.M. Gaye, A.R. Maurer and F.M. Seywerd
   JOURNAL:Scientia Horticulturae 47: 59-66 (1991).
   
8. TITLE: Honey bee visitors and fruit set of cantaloupes
   ABSTRACT: Fruit set and marketability of cantaloupes (Cucumis melo L., var. reticulatus Naud.) in Yuma, Arizona, were correlated with visits by honey bees, Apis mellifera L., up to 13-14/flower. The concept that the stigma is receptive for only a few minutes is proposed. One honey bee for each 10 perfect (hermaphroditic) flowers in the field should ensure visitation during the period of receptivity.
   AUTHOR: S.E. McGregor, M.D. Levin, Robert E. Foster
   JOURNAL: Journal of Economic Entomology 58(5): 968-970.
   
9. TITLE: Insect pollination is necessary for the production of muskmelons (Cucumis melo v. reticulatus)
   ABSTRACT: Inadequately pollinated muskmelon flowers on normal or nectarless plants dropped or developed into malformed fruits. Nectarless muskmelons planted in small numbers among normal plants were visited regularly by honeybees, and they set fruits as well as normal plants in such arrangements. Nectarless muskmelons planted in large numbers with a few normal plants among them were visited occasionally by bees, and they set fruits late and erratically. Nectarless muskmelons planted in isolation were avoided by bees and set very few fruits.
   AUTHOR: G.W. Bohn and G.N. Davis
   JOURNAL: Journal of Apicultural Research 3(1): 61-63 (1964).
   
10. TITLE: Pollination of melons
    ABSTRACT: Peter conducted a pollination trial at Bericon, which is just outside Griffith, New South Wales, Australia. From the experiment he found that in comparing vines with honeybees and vines without honeybees - the presence of honeybees increased average rockmelon weight by 40% and increased total number of rockmelons by 25%.
    AUTHOR: Peter Williams
    JOURNAL: The Australian Bee Journal Vol. 68(7): 18-21 (1987).
    
11. TITLE: Pollination of melons in greenhouses
    ABSTRACT: Honeybees visited watermelon flowers adequately in polyethylene greenhouses resulting in a set of fruit. Between 41% and 95% of the flowers visited by bees set fruit, while no fruit was set on flowers which bees were prevented from visiting. Honeybees also flew satisfactorily and visited muskmelon flowers in a large fibreglass greenhouse and a good crop of melons resulted.
    AUTHOR: Hayward G. Spangler and Joseph O. Moffett
    JOURNAL: Gleanings in Bee Culture 107: 17-18 1979.
    
12. TITLE: The pollination of melons in air inflated greenhouses by honey bees
    ABSTRACT:The behaviour and pollination effectiveness of honey bees, Apis mellifera L., were studied in an enclosed environment.
    Four groups of melon plants, Cucumis melo L., were grown in an inflated polyethylene greenhouse and exposed for variable times to bee pollination. Blooms were shielded from bee visits with gelatin capsules.
    Plant blooms shielded from bees during the entire experiment produced no edible melons. The production of plants with blooms exposed for various times did not vary significantly. Seed counts, percent soluble solids, and weights of melons indicated adequate pollination. Variable carbon dioxide concentrations within the greenhouse appeared to affect the soluble solids percentages in mature melons. Bee activity was enhanced by the presence of supplemental pollen cake.
    AUTHOR: William A. Iselin, Merle H. Jensen and Hayward G. Spangler
    JOURNAL: Environmental Entomology 3: 664-666 1974.
    
13. TITLE: Honey bee visit numbers and watermelon pollination
    ABSTRACT: Honey bee, Apis mellifera L., visits to watermelon flowers were mechanically controlled to determine how many were needed to pollinate a single flower. Although there was some fruit development even after only one visit, 8 visits were considered the minimum required for normal development. A method of measuring field bee activity in terms of visits per flower per hour and factors in distribution of pollen on the flower by bees are discussed.
    There was a positive relationship between fruit set and ovary length. Fruit set following bee visitation generally increased from 6 to 9 am. and from 6 to 10 am following hand pollination. According to the method of measurement used, field bee populations exceeded the minimum necessary for fruit set in 2 years of observation. Honey bees were used at the rate of 1 colony per acre (1 per 0.41 ha).
    AUTHOR: Warren C. Adlerz
    JOURNAL: Journal of Economic Entomology Vol. 59(1): 28-30 (1966).
    
14. TITLE: Cucurbits
    AUTHOR: Robinson, R. W. and Decker-Walters, D. S.
    JOURNAL: Crop production science in horticulture 6, CAB International.
    
15. TITLE: Cantaloup production with honey bees
    ABSTRACT: In the Salt River Valley of Arizona a randomised block experiment on cantaloups with four types of bee treatments was maintained with the use of honey bee colonies and large plastic screen cages. Studies were made of bee activity on cantaloup flowers and its affect on melon production.
    Commercial production of cantaloups without the aid of pollinators was impossible. Honey bees were the only pollinators present in the area. Melon production was increased by placing honey bee colonies in the cages with the cantaloup flowers. Under these conditions the melons set nearer the crown and were sweeter, larger and had more seeds than those produced in the open plots.
    The percentage of soluble solids in the melons was negatively correlated with the distance from the crown. Size was correlated with the number of seeds. Melons containing fewer than 400 seeds were usually below marketable size and misshapen. Undersize culls were associated with insufficient bee visitation.
    The melon flower opened between 7 and 8 am and nectar secretion began at once. About 3 mg of nectar was produced by 11 am after which secretion apparently ceased in the staminate (male) flower. In the hermaphrodite flower, nectar secretion continued on into the afternoon with a total of 18 mg being produced.
    Bee activity began soon after the flower opened and reached a peak shortly before noon, with little activity in the afternoon. Individually, the cantaloup flower produced twice as much nectar of about the same sugar content as did the alfalfa flower, but alfalfa produced 300 times as many flowers to the hectare. Cantaloup flowers were attractive to bees, but provided little honey for the beekeeper.
    Thrips, beetles and native bees proved to be ineffective in cantaloup pollination. Care in the use of insecticides is necessary to protect pollinators. 2.5 colonies per ha is suggested as being adequate to insure thorough pollination of cantaloups.
    AUTHOR: McGregor, S. E. and Todd, F. E.
    JOURNAL: Journal of Economic Entomology (1952) 45(1); 43-47.
    
16. TITLE: The influence of climatological factors on anthesis and anther dehiscence in the cultivated cucurbits. A preliminary report.
    AUTHOR: Seaton, H. L. and Kremer, J. C.
    JOURNAL: Proceedings American Society for Horticultural Science 36: 627-631 (1939)
    
17. TITLE: Cantaloup production increased with honey bees
    AUTHOR: Taylor, E. A.
    JOURNAL: Journal of Economic Entomology 48(3): 327 (1955).

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