16 mars 2015

The latest in kiwi pollination

Few crops are more challenging to pollinate than kiwi. Here’s the reason. For high fruit quality a large number of pollen grains per flower (> 3000) are required. Nectar production in kiwi flowers is generally poor, resulting in low attractiveness to honeybees. Furthermore, kiwi plants are “dioecious” meaning that male and female viable reproductive structures are on separate plants. The only way to set fruit is through cross-pollination. The proportion of non-fruit bearing, and thus “unreproductive” male plants in the orchard is generally limited, e.g. often 1 male plant to 5-8 females is advised. This limits availability of pollen. 

This explains why, in several countries, technologies for pollen collection and assisted pollination have been developed. Both dry and wet pollen spraying techniques are being utilized. Assisted pollination includes both manual and mechanical pollination techniques.

Assisted pollination techniques do allow to achieve good fruit quality. However, they are often not easy to apply. Growers either need to collect pollen themselves or have to purchase pollen from third parties, which should then be of high quality and disease-free. The pollen needs to be applied on the flowers. This process is labor intensive and often, wasteful in terms of pollen consumption. (e.g. with pollen spraying only a small fraction of the pollen ends up on the flowers).

The use of hormones as an alternative to actual pollination is also subject to more and more restrictions and is prohibited in certain countries.

Biobest bumblebees can help address the kiwi pollination challenge. Bumblebees are keen to visit kiwi flowers and will carry large pollen loads and pollinate effectively. They fly at low temperatures and don’t mind the low light intensity which is often found under a dense kiwi canopy. They’ll also work well under nets and plastic tunnels. Biobest also has a technology to deal with situations with insufficient natural presence of pollen. Use Biobest’s patented Flying Doctors® technology. Apply a small amount of pre-collected pollen in the dispenser. Our Flying Doctors® will carry it straight to the female flowers. No pollen wasted. Biobest tested this technology in collaboration with Zespri in Italy and was able to demonstrate optimal pollination. Pollen consumption and labour are only a fraction of what is required with other assisted pollination techniques such as wet or dry spraying.

A short movie is available in English, French and Italian to demonstrate this technology. For full information request our pollination info sheet KIWI from our Marketing Department.