Heikki Hokkanen & Ingeborg Menzler-Hokkanen

Department of Agricultural Sciences University of Helsinki, Finland

OECD Conference on ”Innovations in Organic Food Systems for Sustainable Production and Enhanced Ecosystem Services”, Long Beach 1-2 November 2014

Managing bees for delivering biological control agents and improved pollination in berry and fruit cultivations

Structure of the presentation 1. Concept and overview of entomovectoring

2. Europe-wide collaborative study ‘BICOPOLL’

3. Bottlenecks to implementation and success

4. Prospects for further applications

Entomovectoring for biocontrol

Insects can transport significant amounts of beneficial biocontrol organisms attached to their body hairs Examples

- microbes such as fungal and bacterial antagonists of plant diseases - insect pathogenic organisms (fungi, bacteria, viruses)

Usually the antagonist is transported into a flower visited by the insect, but sometimes on leaves of plants

Overwhelming majority of research has focused on the use of honeybees as vectors.

Bumble bees and solitary bees can also be utilised, but their applicability has only been tested to a limited extent.

Exception: application of managed bumble bees for crop production in controlled environments Commercial development of entomovectoring, available as of 2013

Carefully thought-out details, attractive design ...

Ladder for the bees to climb out

In Italy and in the USA manson bees (Osmia spp.) have been employed for pollination in orchards, and their use as vectors is being studied in BICOPOLL

Dispenser for entomovectoring by Osmia bees

Grey mould of strawberries: first publication in 1992 (Peng & Sutton)

Other plant disease targets: • Fire blight on apple, pear • Sclerotinium-blight of rapeseed • Monilinia on blueberries, cherries • Fusarium core rot on apples • Botrytis bunch rot on grapes • many other potential targets

Infections via the flower result in diseased berries and fruits

Strawberry stamen Stamen colonized infected by grey by antagonistic mould Botrytis cinerea fungus Gliocladium

Calyx of apple colonized by Gliocladium Photos courtesy of Marja-Leena Lähdenperä, Verdera Oy

...microbial colonization of stamens of apple

Photos courtesy of Marja-Leena Lähdenperä, Verdera Oy

Colonization by Fusarium avenaceum and other pathogenic fungi

Colonization by the antagonist Gliocladium catenulatum

Flower infections cause blossom-end rot and core rot of apple

Fusarium avenaceum core rot of ’Santana’ (left) and of of ’Gala Schnitzel’ (right)

Photos courtesy of Marja-Leena Lähdenperä, Verdera Oy

BICOPOLL case study: Grey mould Botrytis cinerea Grey mould colonizes the anthers of strawberries

In Finland grey mould causes annually10-20 % yield loss and ≈ 5 million euro economic loss

Photo: M-L Lahdenperä, Verdera Oy

The grey mould [Botrytis cinerea] antagonist Gliocladium catenulatum is a parasitic fungus preventing the growth of many plant pathogenic fungi. Modes of action: parasitism, competition, nutrient depletion – but it does not produce antibiotics

The biocontrol challenge: how to colonise all the strawberry anthers in the field with the antagonist, before the grey mould fungus does it? Options: 1. spray the antagonist with

conventional sparying equipment

2. use insect vectors to carry the antagonist spores to the flowers, e.g. honey bees

The biocontrol challenge: Spraying the antagonist has resulted in unsatisfactory control (Prokkola & Kivijärvi 2007). WHY? Consider: • do enough spores reach the target site: anthers on the flowers? • do the antagonist spores reach the anthers in time to stop the grey mould development? (race to colonise newly opened flowers)

The biocontrol challenge: The target surface area (anthers in flowers) covers about 1 cm2 ... 1 ha = 100 million (108) cm2

... spraying 400 g of Prestop / ha (on average about 108 spores per gram) brings about 400 spores into the flower target area In contrast, if 400 g of Prestop is target delivered to all the strawberry flowers in one hectar of the field (about 4 million flowers/ha), about 10’000 spores per flower are delivered.

The powder contains about 107-109 spores (cfu)/g

A bee leaving the hive carries about 103-104 spores (cfu) On average, honey bees visit each strawberry flower

10 times per day ... therefore: CONTINUOUS protection A mean of ≈ 103 spores (cfu)/flower has been measured

A few hundred spores (cfu)/flower are needed for control

Inoculum dispenser ’BeeTreat®’

Exit of bees from the hive, below the plexiglass

Entrance of bees

Landing platform

Entomovector technology: Bee-vectored biocontrol of plant diseases and pests

Comprehensive on-farm research

During 4 years of a pilot study in Finland, on average 4 strawberry farms were involved each year in intensive studies => 16 farm-years

Four treatments were included:

1. Unprotected strawberry as control (Bee-, Spray-)

2. Standard fungicide treatments (Bee-, Spray+)

3. Bee-disseminated biocontrol, no fungicides (B+, S-)

4. Both bee-disseminated biocontrol and fungicide sprays (Bee+, Spray+)

Biological precision control protected the berries from grey mould infection as well as chemical fungicide treatments in all weather conditions

Bee-vectored biocontrol provided higher marketable strawberry yields than chemical treatments

0

200

400

600

800

1000

1200

1400

Ei torjuntaa, ei pölytystä Pelkkä pölytys Pölytys + biotorjunta

Yiel

d g/

m

Terveitä

Homeisia100%

158%

205%

Impact of bee-pollination and bee-vectored biocontrol of grey mould on the marketable strawberry yield on an organic farm

Hevonniemi organic farm, Vehmersalmi, summer 2008 http://www.hevonniemi.fi

No mould control, No mould control Mould biocontrol no pollination bee pollination bee pollination

Healthy

Mouldy

Joint field experiments now in ten countries in Europe, on strawberry

Field test in Italy 2012

Field experiments in Estonia 2010-2012

Using bumble bees: site 1 site 2

Using honey bees: significant difference in 2 out of 3 study years (almost no disease incidence in 2011)

Estonia: Yield weight, berry weight

Higher overall yield with Higher individual berry entomovectoring weight

Turkey 2013

Mouldy berries Yield

Slovenia

Bee visits/plot

Slovenia

Impact of mould control on strawberry shelf-life: ’sales-box-tests’

Additional benefit: shelf-life is extended

0

10

20

30

40

50

60

70

80

90

100

0 2 4 6 8 10

Days in the sales-box

Prop

ortio

n of

mou

ldy

berr

ies

(%)

M-R-M-R+M+R-M+R+

Strawberries remained healthy at room temperature twice as long, if grey mould was controlled at the time of flowering

So far, all field tests in all countries using entomovectoring and Gliocladium catenulatum (Prestop Mix) have shown excellent control results on strawberry.

Commercial uptake of honey bee vectored precision biocontrol on strawberry in Finland. The method has been approved for general use in 2008; now >10 % of all growers use the method.

Main outcomes from BICOPOLL Pan-European field trials have consistently shown, using strawberry as a

case study, that bee-disseminated biocontrol of the grey mould provides equal or better crop protection than chemical fungicides.

In organic strawberry, marketable yields significantly increase, often by over 50 %.

Improved pollination accounts for about half of the yield increases. Honey bees, bumble bees, and solitary bees can all be used for

vectoring beneficial biocontrol microbes Efficacy and impact of the entomovectoring technique can be improved

by management of hives (size, location, and properties), vegetation management, and optimization of dispensers and properties of the microbial preparate

No negative outcomes on products (berries, bee-products) have been detected, nor on humans or non-target organisms;

The concept has proven to be effective on a wide range of crops, such as strawberries, raspberries, pears, apples, blueberries, cherries, and even grapewine

Bottlenecks to implementation and success 1. Availability of suitable entomovectors

bees for entomovectoring, plus diversity of natural pollinators

2. Availability of effective antagonists specific strains and optimised formulations registered for the target applications

3. Lack of knowledge on bee behavior and management steering bees to go to the target crop and flower

4. Dedication and knowledge level of operators it appears easy – but it needs to be carried out precisely, and with some knowledge of the underlaying ecology of the organisms

… but do they also visit our crop, and its flowers?

Honey bees forage where the colony decides …

Steering the bees: small honey bee colonies vs. big

Patterns of bee visits on strawberry in Finland

5 farms 35 separate observation events >11 hours of obs.

445 individual flowers obs. 10-20 flowers at a time

Prospects for further applications

All results from BICOPOLL are globally applicable. We have on-going collaborative research using these techniques and/or their modifications in Australia, and emerging collaborations in South-East Asia, South- America, the Caribbean, and South Africa. Experience in Finland shows that entomovectoring can easily be integrated also in conventional production of strawberry.

Coleopteran pests on oilseed rape trap crops, effectively controlled by Metarhizium anisopliae vectored by honeybees

Pollen beetles Cabbage seed-pod weevil

Pioneering work in Australia on entomovectoring in grapewine

Botrytis bunch rot on grapewine

Summary Bee vectored biocontrol combines two key ecosystem

services: biological control and pollination Biocontrol of several key plant diseases and pests on fruit

and berry crops is possible, and often provides a level of control equal or better than a full chemical pesticide program; for organic farming, this usually is the only option for pest and disease control

Enhanced pollination alone brings yield and quality increases in the range of 10% to 50%, depending on the crop

Intensified R&D, as well as knowledge transfer and training, are required to exploit the potential of entomovectoring

Promotional video of Biobest for ’Flying Doctors’

http://www.youtube.com/watch?v=nPTistUfW-Y

Thank you

for your attention

... and thank you for inviting me to give this presentation