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By: Daniel E. Mullins
Extension Horticulture Agent
Poor Fruit Set in Some Areas Reveals the Importance of Bees
Some home vegetable gardeners are finding it increasingly difficult to grow the cucurbit crops. Sometimes known as vining crops these include squashes, cucumbers, watermelons, cantaloupes and pumpkins.
These crops have a special pollination requirement which appears to be limiting fruit set. They have both male and female reproductive parts on the same plant, but in separate flowers on the vines. Male flowers look like simple yellow flowers, yet they contain only the stamens, or male reproductive organs.
The female flower starts out with what appears to be a small squash, cucumber or other cucurbit fruit at the base of the female blossom. Until pollinated, it is not a fruit, but an unfertilized ovary. When this structure first appears with blossom attached, it is often mistaken for a developing fruit. If not well pollinated, it soon shrivels rather than developing further.
Complete pollination requires that the pollen from the male flowers be moved and deposited on the female flower’s receptacle at just the right time. This job is done mostly by honey bees. When active in sufficient numbers they are very efficient at this task.
Good pollination therefore requires that there be enough bees in the immediate area. Bees work best close to home and are most efficient within one-fourth mile of the hive. Though they are known to work a mile or more away, their ability to consistently pollinate crops at that distance would be greatly reduced.
Bees are so important to farmers who produce the cucurbits that the placement of hives near each field has become a routine procedure.
The home gardener who grows cucumbers, squashes and other cucurbits in a highly developed residential area is sometimes at a disadvantage due to a shortage of bees. There is often an absence of sufficient wild bees and few people keep hives in suburban settings.
Considering the fact that cucurbit flowers require multiple daily visits by bees to develop high quality fruit, there appears to be a need for more bee keepers. There is plenty of information that is available for anyone who is interested in beekeeping. The Escarosa Beekeepers Association offers local educational programs and advice as well as a swarm collection service for hobbyists and commercial producers alike. The Association can be contacted by telephone at 850-478-7690. The local Extension office can also provide information on this subject.
Home gardeners who grow a few cucumber or squash plants can try pollinating by hand in the absence of bees. To do this, go to newly opened flowers each morning. Using an artist’s brush, remove some pollen from male flowers and carefully transfer it to each female flower’s receptacle. The receptacle is located in the center of the flower with a sticky substance on its surface. Though you won’t do the job as well as the members of a nearby bee hive would do, it beats having a crop failure.
Question of the Week: I have a key lime tree that is five years old and has not produced any fruit. Any advice?
Answer: I trust that you are growing it in a container and can move it indoors during the winter. The key lime is very cold sensitive. Give it plenty of sunlight and hold back to some degree on the fertilizer. It is not a heavy feeder and excessive fertilization can have negative effects.