It has been well documented that effective pollination is a limiting factor in lifting yields in tree crops.
Not only does poor pollination limit fruit set but also fruit size and uniformity is compromised.
Because of the dense nature of modern orchards, natural air flow of pollen is much reduced and due to the sheer number of flowers that need to be visited by pollinators there is a significant reliance on other methods of pollination.
Tree crop flowers are visited by many native species of nectar and pollen collecting insects including wasps, flies, ants and other native bugs. However, the major pollinators in most commercial Australian orchards are European honeybee (Apis mellifera).
Flowering in commercial orchards can occur very early in spring (almonds) over hours, days or even weeks. Hence bees need to work through very cool mornings and days and in the case of some inflorescence it may take weeks to be fully pollinated.
This means bees have to be attracted into the field in less than favourable conditions multiple times over an extended period for effective pollination and fruit set to occur.
For example, it takes about 150 bee visits to a macadamia raceme over two weeks for full pollination to take place. Successful pollination requires a high degree of constant movement of bees and arrestment throughout a plantation for effective fruit set and quality (size and uniformity).
How can we make bees work harder in orchards?
There are a number of commercially available products that contain certain volatile chemicals known to attract bees.
Some are feeding stimulants and others mimic the signalling of scouting bees and worker bees. All are designed to increase foraging of commercial European honeybees by attracting them into the crop with a hope this will improve pollination outcomes.
Some products are cover sprayed onto the crop and produce a large bloom of odour over a short period of time. These types of cover sprays remain effective for just a few days but flowering in some orchards occurs over weeks. Hence, frequent applications of these cover sprays are needed for effective attraction over the flowering period.
SPLAT Bloom®
One of the more advanced pollination enhancers to enter the market in recent years is SPLAT Bloom®. SPLAT stands for “Specialised Pheromone & Lure Application Technology”.
SPLAT Bloom is designed to increase foraging range and productivity of bees and inducing them to remain in the treated field for longer periods of time.
Splat Bloom makes bees forage further for longer
Honeybees typically prefer to forage relatively close to their hives and selectively target flowers that offer the most plentiful stores of pollen and nectar.
SPLAT Bloom applied in small dollops directly to the surfaces of plants, steadily releases a semiochemical which is naturally produced by worker bees, called Nasonov pheromone.
The Nasonov pheromone is used by scout worker bees to mark the flowers they visit, indicating to other bees productive sources of pollen and nectar.
When dispersed throughout the field, SPLAT Bloom induces foraging honeybees to regard the treated crop as a desirable food source, thereby preventing them from leaving the field in search of alternative sources.
Field studies
Field studies conducted in apples and almonds showed that treatment with SPLAT Bloom resulted in consistently higher levels of pollination and fruit set in these crops, as compared with untreated control plots.
Application
The great advantage of SPAT Bloom is that the toothpaste like matrix is easy to apply. It is commonly applied by hand using a caulking gun from 750g tubes.
OCP is working on use of drones and a gas driven mechanical applicator that sits on the back of a quad bike, trailer or ute. The plant wax matrix releases the Nasonov pheromone in a controlled manner over an extended time period of up to four weeks.
It is extremely rainfast and resistant to weather making if an effective pollination enhancer over the flowering period of some tree crops.
SPLAT Bloom is supplied in 750g caulking gun tubes and applied at 1.5-3 gram dollops to flowering branches at uniform spacings through-out the crop.
Effective attraction and arrestment can be achieved at 1.5kg (two 750g tube) of SPLAT Bloom at 250-500 dollops per hectare.
Contact OCP 1800 634 204
www.ocp.com.au
See this article in Tree Fruit August 2019
