Bees are indispensible pollinators of fruit trees, vegetable seed and sunflowers. This insect is the key to a successful crop.
For vegetable seed growers in South Africa, the months of October and November are very important – this is pollination time. The outcome of months of hard work (two years in the case of onion seed) and high input costs depends on the work of the honey-bee during these two months.
Many vegetable seed growers and advisers know the
frustration caused by poor pollination or bees that don’t do their work. Although certain climatic factors, such as the cold, rain and wind, cannot be controlled by the producer, there are several things on which the grower must focus to ensure maximum pollination by bees.
A pollination hive should look like this:
Vegetable growers are largely dependent on bee-keepers who usually supply bees for pollination purposes at a cost. For optimum results, producers should know that pollination hives should meet the following criteria:
- Eight of the ten frames in a hive should be full of bees.
- Hives contain from10 000 to 60 000 bees.
- At least four frames should contain 50% young bees.
- The casing should have a young, active queen bee.
- Hives should be brought into an upward building phase (should contain young bees) six to eight weeks before pollination starts.
- Frames should not contain too much pollen or nectar.
- Hives should be disease-free.
PLACING OF HIVES
- Hives should not be placed further than 30 m from the seed plantings.
- Position hives in a dry place, preferably on bricks, old tyres or a stand.
- Take into account the rows of plants – bees prefer to work within rows rather than across rows.
- Take into account the current wind direction, especially in the case of onions, which have a strong smell.
- A constant temperature of 34 °C should be maintained in the hive. If the temperature is too high, more worker bees are needed to cool down the hive. In very warm areas isolation materials such as grass or straw can be placed on top of the hive. The opposite is also true. The sooner the hive becomes warm in the morning, the sooner the bees will start working.
- Hives should not be placed in a straight row next to one another because bees tend to work towards the outer edges of a row. Bees do in fact allow access to bees from another hive if they carry nectar or pollen – otherwise such bees will be killed.
- International research as well as local observation has shown that hives should not be placed among the plantings.
CAUSEs OF POOR POLLINATION
- Unfavourable weather conditions.
- Hives that do not meet the criteria – too few bees and/or young bees.
- Harmful chemicals administered just before or during pollination.
- The taste of nectar can be influenced by certain fertilisers and cultivars.
- Other crops or weeds such as wild mustard, wild radish and other veld flowers that flower at the same time as the seed crop.
- Timing is critical when establishing hives. If hives are established too early, bees will seek alternative food and are unlikely to return, especially to onion flowers.
- Water with an unpleasant odour or taste will deter bees – especially water used for overhead irrigation.
- Irrigation influences the concentration of nectar.
- The presence of bees’ natural enemies – insects such as the Banded Bee Pirate and Yellow Bee Pirate – could hold them ‘prisoner’ in a hive. This poses a problem, especially during dry seasons. Overcome this problem by building tunnels in front of the hive using bales. This allows bees enough time to increase flying speed and bee-catchers do not like the shade in the tunnel.
ROLE OF THE PRODUCTION ADVISER
Our experienced and well-trained production advisers are there to assist the seed grower in all facets of vegetable seed production.
What makes our production team exceptional, is that their advisers have completed a course in practical bee-keeping which enables them to assist the seed grower with all aspects of pollination.
They have also completed courses in National Crop Protection and the National Fertilisation Advisory Course. Two advisers also recently attended an international bee congress. They are assisted by a chemical and fertiliser specialist as well as a production technology division. All the above helps the adviser to assist the producer in order to minimise possible factors that can influence pollination and to ensure maximum yield.