BIO-BEE - Biological Systems Ltd., Kibbutz Sde Eliyahu

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Pollination In Crops » Pollination of Eggplant

Pollination of Eggplant

The flower, pollination and fertilization
The eggplant (Solanum melongena) has a perfect flower with purple petals and green or purple sepals. The anthers are yellow and sit on short filaments surrounding the style. Each anther bears two chambers that open in a round hole at the upper end. The style may be longer, equal, or shorter, than the cone of stamens surrounding it.

The eggplant is a self-fertile and self-pollinating plant. However, cross-pollination through insects is possible and in many cases desirable.
The eggplant flower lacks nectar.
The flower appears either alone or in clusters of 2-8 flowers, with the lowest one in the cluster being the most developed.

The bumblebee is capable of shaking the flower using the “buzz-pollination” mechanism in which it specializes.
In open areas the wind carries out the shaking action. In protected structures hormones are used to develop seedless fruit, according to the market demand. However these fruit are soft and have a short shelf life.
For certain markets there is a demand for longer lasting fruit, hence bumblebees are commonly used for pollination.

The hive
When it leaves the factory, the standard colony for eggplant consists of one queen, a few dozen workers, pupae, larvae and eggs. The hive does not contain males. This is a strong colony with an anticipated life expectancy of 5-10 weeks.
The hive is provided with a sugar-water solution, a substitute to the nectar lacking in the eggplant flower. The ‘Nes-Bee’ system, placed at the bottom of the hive, continuously provides the sugar-water that is vital for the proper functioning of the colony during the entire period of its presence in the greenhouse. This system is maintenance free.

Introduction scheme
For eggplant in protected structures, 7-10 standard hives provide pollination for one ha. for a period of 5-8 weeks. The number of hives placed for each unit of area varies with the variety/type of eggplant, and the intensity of its blossom.
During winter in non-heated structures, when night temperature drops below 15oC for three consecutive nights, non-viable pollen will be produced. Then the bumblebee activity will be of no effect.

Field advisory service
It is possible to see the results of bumblebee visitation in an eggplant flower within about a day. A distinctive brownish stain is left on the cone of stamens.
Follow-up on the activity of the bees as well as the state of the hives is carried out in three ways:
1) Checking open flowers of more than two days old, or those who have completed their blossom, for signs of bee visitation (see above).
2) Direct observation on bumblebees visiting flowers.
3) Observation of entries and exits of worker bees to and from the hive. The last two checks should take place during the bees’ peak hours of activity.