FAR Foundation ForFOCUSFOCUS Arable Research Issue 07 November 2012 ISSUE Crop Pollination 7 • The process of pollination • Honey bee biology and behaviour • Obtaining and managing honey bee colonies for pollination • Orchard/crop management • Crops • Towards diversifying pollinators in crop fields ® ADDING VALUE TO THE BUSINESS OF ARABLE FARMING™ Introduction Pollination is the movement of pollen from the anthers of a flower to the stigma of the same or a different flower. Pollination is one of the most important parts of the economic production of many crops. However, it is often the most poorly understood and least likely to be optimised. In some cases, it is not managed at all and growers just trust there will be enough bees or other insects in the vicinity of the crop to ensure that pollination occurs. Even if beehives are introduced for pollination, their performance may not be optimised and the levels of pollination may not be measured. For many crops, obtaining optimised and reliable pollination may be one of the best ways of improving the economics of the production of the crop. The aim of this manual is to provide growers, beekeepers, and pollination specialists with the information necessary to optimise the pollination of insect-pollinated commercial crops. The manual begins (Section 1) with a description of the process of pollination, including a summary of the species involved. Honey bee biology and behaviour is described in Section 2. Section 3 covers issues around obtaining and managing honey bees for pollination. In Section 4, management strategies to protect honey bees are outlined while Section 5 covers specific issues related to pollination of a range of crops. Section 6 looks at other pollinating insects such as native bees, bumble bees and flies. This report has been prepared by The New Zealand Institute for Disclaimer Plant & Food Research Limited (Plant & Food Research), which Unless agreed otherwise, The New Zealand Institute for Plant & has its Head Office at 120 Mt Albert Rd, Mt Albert, Auckland. Food Research Limited does not give any prediction, warranty or assurance in relation to the accuracy of or fitness for any particular This report has been approved by: use or application of, any information or scientific or other result contained in this report. Neither Plant & Food Research nor any Mark Goodwin of its employees shall be liable for any cost (including legal costs), Scientist/Researcher, Pollination and Apiculture claim, liability, loss, damage, injury or the like, which may be Date: 24 June 2011 suffered or incurred as a direct or indirect result of the reliance by any person on any information contained in this report. Stuart Tustin Science Group Leader, Crop & Fruit Production Systems Limited protection Date: 24 June 2011 This report may be reproduced in full, but not in part, without prior consent of the author or of the Chief Executive Officer, The New Zealand Institute for Plant & Food Research Ltd, Private Bag 92169, Victoria Street West, Auckland 1142, New Zealand. 2 FAR Focus 7 Crop Pollination Contents 1. The process of pollination ................. 2 4. Orchard/crop management ............. 30 • 1.1 Flower parts • 4.1 Conditions within the orchard • 1.2 Self and cross pollination • 4.2 Pesticides • 1.3 Vectors for pollen movement • 4.3 Surfactants • 1.4 Bee species • 4.4 Removing beehives before spraying • 4.5 Mowing grass 2. Honey bee biology and behaviour ... 10 • 4.6 Beekeeper/grower co-operation • 2.1 Feral honey bee colonies • 2.2 Beehives 5. Crops 34 • 2.3 Honey bee castes • 5.1 Buckwheat • 2.4 Stinging • 5.2 Carrots • 2.5 Swarming • 5.3 Field beans and Broad beans (Vicia Faba) • 2.6 Varroa • 5.4 Linseed • 2.7 Honey bee foraging • 5.5 Lotus, Birdsfoot - trefoil • 5.6 Lucerne (alfalfa) 3. Obtaining and managing honey • 5.7 Oil Seed Rape bee colonies for pollination ..............17 • 5.8 Radishes • 3.1 Obtaining hives • 5.9 Red clover • 3.2 Colony strengths • 5.10 White clover • 3.3 Queens • 3.4 Swarming 6. Towards diversifying pollinators • 3.5 Identifying problems with in crop fields .......................................41 colonies - auditing • 6.1 Value of pollinator diversity • 3.6 Managing colonies • 6.2 Towards increasing pollinator diversity • 3.7 Sugar syrup feeding within crops • 3.8 Robbing • 3.9 Pollen trapping and feeding Appendix ................................................ 47 • 3.10 Attracting honey bees to flowers • 3.11 Honey bee stocking rates © Foundation for Arable Research (FAR) DISCLAIMER This publication is copyright to the Foundation for Arable Research and may not be reproduced or copied in any form whatsoever without written permission. This FAR Focus is intended to provide accurate and adequate information relating to the subject matters contained in it. It has been prepared and made available to all persons and entities strictly on the basis that FAR, its researchers and authors are fully excluded from any liability for damages arising out of any reliance in part or in full upon any of the information for any purpose. No endorsement of named products is intended nor is any criticism of other alternative, but unnamed product. 1. The process of pollination 1.1 Flower parts 1.2 Self and cross pollination 1.3 Vectors for pollen movement 1.4 Bee species 1.1 Flower parts To gain the best understanding of the information provided in this manual, it is necessary to have an understanding of the names of different parts of flowers, their appearance and function. The flower parts are (Figure 1): • Sepals that enclose the flower buds. They open and fold back so the petals can open. • Petals that enclose the reproductive Stigma structures. In insect pollinated flowers, these are usually coloured and conspicuous to attract insect visitors. Anther The petals usually have to open before Pistil pollination can occur. • Anthers that produce the pollen. Anthers are usually at the end of a Filament filament. An anther and its filament are Ovary referred to as a stamen. The anthers must open or split to release the pollen. Petal • Pollen grains contain the male genetic Sepal material that must be moved to the female reproductive structures. • Stigmas, which are at the end of a pistil, are the female structures on which the pollen must be deposited. • The ovary is normally at the base of a flower and contains from one to more than 1000 ovules. • Ovules are the female structures that must be fertilised to produce seeds. • Nectaries produce nectar to attract animal flower visitors. These are usually situated at the base of the petals. Figure 1. Diagram of a generic insect pollinated flower. Seeds and fruit are expensive for a plant to produce, pollen grain wall (germination) and grow through the while few resources are required to produce a pollen stigma tissue to reach the ovule. The pollen tube then grain. For this reason, plants usually produce relatively combines with an ovule to create a seed (fertilisation). few ovules compared to the number of pollen grains they produce. There may be millions of pollen grains For pollination to occur, all of these things must happen. produced for each ovule. For the production of a commercial crop it needs to happen reliably and often. To produce a seed, pollen must be moved from an anther to the stigma of a compatible flower that Over millions of years, plants have evolved complex is capable of setting seed. To start the process, relationships with the agents that move the pollen to the anthers must open or split to expose the pollen their stigma. For most plants, these systems work (dehiscence), and the pollen must then be transported sufficiently well to ensure enough seeds are produced while it is still alive. for the survival of the species. However, the pollination of plants grown commercially can be much more Depending on the plant species, the pollen may have difficult. Often, humans have selected plants without to be moved a few millimetres or many metres. Once reference to their pollination systems. This can be on the stigma the pollen tube must break through the seen in hybrid seed production in radishes. For a The process of pollination 3 normal radish flower, pollen only has to be moved a Natural selection of plants has favoured the transfer few millimetres to reach a stigma on an adjacent flower. of genetic material between different plants (out- However, to produce hybrid radish seeds, the pollen crossing) to maximise the species’ ability to cope with may have to be moved several metres to another plant. variations in its environment. Although plants requiring Plants are also often now grown in places where the out-crossing are the most common, many plants are pollinators they have evolved with are not present. completely self fertile. Further complicating matters, plants are also now forced to grow in a different manner to how they would As well as plants that are completely self fertile and grow in their natural environments. For example, kiwifruit plants that require out-crossing, some plants are partly is a vine that climbs trees in its natural environment in self fertile. They can produce seeds by themselves forests in China; however, commercially it is grown on but will produce more if they are cross pollinated e.g. structures that are less than 2 m tall. strawberries. In their natural environment plants often grow in relatively small patches or as isolated plants. There are usually 1.3 Vectors for pollen sufficient pollinators in these natural ecosystems to movement ensure they are pollinated. However, commercial crops are usually grown in large monocultures, sometimes There are a large variety of vectors in natural kilometres in extent. In such situations there are usually ecosystems that carry pollen between flowers, too few natural pollinators in the vicinity of the crop to including wind, water, insects, birds, bats, and reptiles.