Squash yields

animated_gif_bees_06  In the ‘Squash Pollinators of the Americas Survey’ (1) an explanation is given of bees and their importance for squash yields and use in big agricultural squash production.

Squash flowers are unisexual, and so require a bee to move pollen from male to female flowers.   Honeybees (Apis mellifera) are typically provided for commercial squash pollination, but native specialist bees, the so-called “squash bees” – are very common, often the dominant pollinators of many wild New World Cucurbita (the genus that includes squashes and gourds). Where squash cultivation has extended beyond the ranges of wild plants, representative species of squash bees have followed (in North America, anywhere outside the Southwest; in South America, areas of southern Brazil). (1)

Male flowers outnumber female ones by about 3 – 10 to 1. This helps ensure pollination of the female flowers which must be pollinated to set fruit. Bees are the most important pollinators, and seed number and fruit weight increase proportionally to the amount of pollen transferred to the stigma. In west Tennessee, USA (5) each flower opens for only one day, usually in early morning, but if it’s hot, the flowers close early. Consequently, as with other cucurbits, good bee visitation in the morning is important, and it is recommended that 1 honeybee (Apis mellifera) beehives per acre is used (2 or more beehives per hectare).

In most regions and islands of the Philippines sufficient bee pollination would need to rely on the available native bees.

Squash is commonly grown in the Philippines throughout the year. (3) It is usually grown in home gardens and commercial scale for its immature fruits, young shoots, flowers and seeds. In some places, intercropping squash with other crops like corn, sugarcane and coconut is practiced. It is commercially cultivated in Ilocos Region, Cagayan Valley, Southern Tagalog and Bicol Region. The provinces producing semi-commercial scale are Davao, Leyte, Nueva Ecija and Batangas. Like other cucurbits, squash is recognized as an important source of vitamins and minerals.

As the ‘High Value Crops Development Program’ website (3) guide states… Bees are the most common agent of pollination for cucurbit crops. Therefore, an ample supply of honeybees should be introduced into production fields to enhance and ensure pollination. Poorly pollinated fruits will have poor development which usually results in unmarketable fruits. (It is noted that the provinces where squash is currently commercially cultivated have probably good bee populations and a greater proportion of beekeepers, than many other regions in the Philippines.)  The HVCDP website (3) guide also states… To increase fruit setting when insect pollinators are few, hand pollinate by inserting the male flower of the same age to the female flower between 6:00 and 8:00 in the morning.

Squash pollination

Excerpt from HVCDP Squash Production Guide (3)

Currently uncontrolled honey hunting is actively continuing the removal of the key pollinators. What are the prospects (2) for large scale efficient agricultural squash production if there are insufficient bees in many islands and regions of the Philippines to produce good squash yields?

This website links directly to a great many references which repeatedly demonstrate the importance of considering the pollinator environment, which includes the Food and Agriculture Organisation (4) (5). However, the Philippine Department of Agriculture currently does not appear to be fully considering pollination issues, and how these may be impacting on the millions of farmers across the country.

During the history of humankind, bees have been doing the vital job of pollinating for free, but it is becoming evident that the Philippine rural communities can no longer take this service for granted. Comparisions to other countries such as Vietnam indicate a different scenario where they are not encountering the same issues – where plentiful bees produce 300 times more honey than the Philippines and coffee yields are 5 times greater than the Philippines.

There is no evident disadvantage to re-establishing the native bees in the Philippines and improving the pollinator environment, but the advantages are potentially enormous.

References …

1) Squash Pollinators of the Americas Survey
http://www.ars.usda.gov/Research/docs.htm?docid=16595

2) Squash (hybrid) seed production: Providing a bright future for Sto. Niño farmers
http://www.bar.gov.ph/digest-home/digest-archives/123-2011-1st-quarter/428-hybrid-squash-seed-production-providing-a-bright-future-for-sto-nino-farmers

3) High Value Crops Development Program (RA 7900)
Department of Agriculture in Philippines
http://hvcdp.da.gov.ph/

4) List of crop plants pollinated by bees
http://en.wikipedia.org/wiki/List_of_crop_plants_pollinated_by_bees

5) Pollination: Crop Pollination Requirements
http://www.ent.uga.edu/bees/pollination/crop-pollination.html

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