managing for maximum productivity and quality

Managing for maximum

productivity and quality

Simon Newett

Department of Agriculture and Fisheries

Nambour, Queensland

Today s talk

1. Phytophthora root rot

2. Irrigation

3. Nutrition

4. Canopy management

5. Spotting bug


Managing root rot is your highest priority and always will be.

“Never let up”!

How far can this car go?

Trees with root rot

do t ha e heels !

Drainage is your highest priority

1. 1 to 1.5m well drained soil

2. Ensure that water lies nowhere!

3. Plant on mounds

Timing is CRITICAL for phos acid!!

- for applications (and monitoring)

Once spring leaf flush has hardened

& feeder roots actively growing:

• Sick trees – inject all

• Healthy trees – inject or spray if

root level is less than 90ppm

Once summer leaf flush has

hardened & feeder roots

actively growing:

• Main time to apply phos acid

to all trees (8 week window)

• Sick trees must be injected

• Healthy trees can be sprayed

or injected

Key practices for root rot

Follow the Phytophthora management poster

NO SHORT CUTS!

1. Excellent drainage & plant trees on mounds

2. Test level of phosphorous acid in feeder roots

3. Apply phosphorous acid every autumn

4. Apply phosphorous acid in spring if needed

5. Inject sick trees

6. Inject OR spray healthy trees

7. Ensure correct timing of phos acid applications

8. Do t o e ate . Redu e irrigation to sick trees

YouTube video in BPR

It is on your far a d it o t go a ay!

Give it half a chance it will get away from you

After Phytophthora root rot management

irrigation is probably the next highest priority.

2. Irrigation

Avocado orchard management

priorities in Chile

1.Irrigation

2.Irrigation

3.Irrigation

4.Nutrition and pruning

Francisco Mena, leading avocado researcher &

consultant

The irrigation conundrum

Avocados have a high water requirement

and are inefficient at taking up water . . .

but they are also sensitive to wet soils

because feeder roots have a high oxygen

requirement & they are prone to root rot

Consequences of under watering

Moisture stress = fruit drop

Water stress = ringneck (incomplete abscission)

Water stress = death of seed coat = small fruit

Water stress in first 6 weeks after fruitset = poor

shelf life due to low calcium levels

Water stress = poor quality fruit

e.g. vascular browning

Consequences of over watering

U de -irrigating will affect

o e seaso s p odu tio , but over-irrigating will affect

several yea s

Francisco Mena, Chile, 2015

Phytophthora root rot

Drowned avocado tree

Waterlogging = fruit fall &

uneven ripening

How to estimate water need?

1.Water used by tree is directly related

to evaporation

2.If daily evaporation is 10mm water,

trees will need 10mm x crop factor

e.g. 10 x 0.7 = 7mm

3.Sometimes, e.g. during flowering or

leaf flush, crop factor may be 1 or

more

The o ept of RAW

Readily A aila le Water

RAW is the water that a plant

can easily extract from the soil

Drainage

Water availability for avocado

Not

available

Limited

availability Readily

available water

(RAW)

Saturated soil 0 kPa

Wilting

point

Refill point -20 kPa

Full point

- 8 kPa

Dry soil -1500 kPa

Refill point for grapes

-40 to -60 kPa

Readily Available Water (RAW) for avocado

Soil

texture

Soil water extractable

between -8 and -

20kPa for avocado

(mm/cm)

(assumes 0.5% OM)

Sand 0.33

Sandy

loam

0.46

Sandy

clay loam

0.39

Clay loam 0.30

From: Waterwise on the farm, NSW DPI Fact sheet,

2004


Example: Sandy loam

Main root zone 20cm

20 x 0.46 = 9mm

Soil

texture


between -8 and -

20kPa for avocado

(mm/cm)

(assumes 0.5% OM)

Sand 0.33

Sandy

loam

0.46

Sandy

clay loam

0.39

Clay loam 0.30


2004


Example: Sandy loam

Main root zone 20cm

20 x 0.46 = 9mm

RAW can be increased by 3 - 4mm for every 1% increase in soil organic matter.

Soil

texture


between -8 and -

20kPa for avocado

(mm/cm)

(assumes 0.5% OM)

Sand 0.33

Sandy

loam

0.46

Sandy

clay loam

0.39

Clay loam 0.30


2004

Any moisture stress will affect fruit size

Irrigation is a key component in

achieving high yields of good quality &

good sized avocados.

For avocados a very focussed and

responsive approach to moisture

monitoring and irrigation is required.

Most critical time for soil moisture

Key times of cycle for moisture

FRUIT GROWTH GRAPH IS S SHAPED (sigmoidal)

Sep Apr Oct Nov Dec Jan Feb Mar May

Fruit

growth

Phase of

exponential

fruit growth

The most critical time to

irrigate for fruit size is

during the 12 weeks after

fruitset when fruit is

growing exponentially

Key practices for irrigation

1. Only plant what you can fully irrigate

2. Design system to cater for peak demand

3. Calculate Readily Available Water (RAW)

4. Install soil moisture monitoring devices

and have a secondary system

5. Monitor soil moisture at least daily

6. Establish Full and Refill points and keep

moisture between these points

Managing soil moisture - irrigate when probes tell you to

Full point

Refill point -20 kPa

-8 kPa

Key practices for irrigation (cont.)

7. Target top 20 to 30 cm but charge up

deeper levels ahead of a peak demand

8. Respond immediately to moisture

needs

9. Expect to irrigate daily in summer

10. Do t o e i igate! 11. Reduce irrigation to sick trees

12. Test the uniformity of your irrigation

system


Mulch

• Mulch will not reduce the water that

the trees actually need, but . . .

• It makes more efficient use of the

water you have (e.g. 40% reduction) • Reduces evaporation from orchard floor

• Over time improves water holding capacity

of soil by increasing organic matter content

(a NQ grower improved organic matter of

soil from 0.5 to 3%, thus increased RAW by

about 9mm)

Suitable mulching materials

15cm of coarse material

• Fibrous, stalky, straw-like or chunky

materials break down slowly and allow

free drainage of water. Avocado wood

chips, sorghum, corn stalks etc

• Sawdust, bagasse, too fine, form a barrier

that initially prevents water penetration,

once wet, they become soggy, dry slowly

and make underlying soil too wet.

• Keep 5cm away from trunks

If you a t ig ops a d a t to minimise alternate and irregular bearing

you eed to feed the t ee

3. Nutrition

a) Healthy root system

Pre-requisites for good nutrition . . . .

b) Good irrigation

c) Regular leaf and soil analysis

d) Highly recommended . . . mulch

Use coarse, free draining material with low N

e) plus . . . The est fertiliser is the a ager s footsteps

Just as i porta t as the leaf sa ple is to go into the orchard and look at the leaves to

o ser e their olour, shi e, size a d shape. Francisco Mena, Chile, 2015

Most important nutrients for

productivity and fruit quality

• Nitrogen

• Boron

• Calcium

• Zinc

Leach easily Must be

balanced

Nitrogen (N)

• Nitrogen is the ‘dynamite’ of plant growth - learn to harness it

• Balance is critical

– Excess N depresses Ca in fruit & encourages excess vegetative growth

– Deficient N depresses yields & fruit size

Tailor N rates to match fruitset load

Redu e ates i a off yea to a oid over-stimulation of vegetative growth

N timing

Little and often with main focus on . . .

• Autumn – to build tree up for flowering

• Spring (after 1st fruit-fall) - for fruit development

& spring leaf flush

• Summer - for fruit size and summer leaf flush

Grae e Tho as re o e datio for extra

N if a large crop is set

1. As soon as it appears that you have an above

average fruitset (when fi st f uit fall is o e …

2. Apply 50% extra* N in fortnightly fertigation

applications for 2 – 3 months till an obvious

spring leaf flush is starting

3. The ai is to get 18 of sp i g leaf flush over the fruit

4. Sample spring leaf flush to check N and adjust if

needed

* Assumes optimum leaf levels in autumn sample

Calcium (Ca)

• The higher the Ca in fruit the better the quality and shelf life.

• Boron & calcium co-dependent

Calcium uptake into fruit

• Most calcium is deposited in the fruit only

during first 6 weeks of growth (before fruit

stomata close up and turn into lenticels)

• If inadequate Ca in soil solution &/or

insufficient soil moisture at this time then

you have missed the boat!

• Rootstocks have major influence on fruit

Ca o te t, Vel i k is good

Boron (B)


• Tricky to get right

• Narrow margin betw. deficiency & toxicity

• Required wherever growth is happening

• Calcium and boron co-dependent

Deficiency Deficiency

Deficiency

Boron toxicity

. . . and leaf fall

Optimum soil boron levels are different

for different soil textures

•Clay 3 to 12 mg/kg

•Clay loam 2 to 8 mg/kg

•Loam 0.75 to 3 mg/kg

•Sandy/sandy loam 0.25 to 1 mg/kg

Also . . . starting rates are also different

for different soil textures

Boron application worksheet

Normal fruit Deficient fruit

Tied up by:

• clay soil

• high pH

• high phosphorous

levels

So preferably apply as

band along drip line

Foliar sprays are

ineffective &

compromise leaf tests

Zinc (Zn)

Key practices for nutrition

1. Attend to irrigation first

2. If fertigating check irrigation uniformity

3. Analyse leaves every autumn (& spring)

4. Analyse soil every 2 or 3 years, check pH

5. Ma age s footsteps!

6. Match nitrogen with crop load

continued . . .


Key practices for nutrition (cont.)

7. Do t o e apply it oge 8. First 6 weeks of fruit devt. critical for Ca

9. Use boron worksheet or get expert advice

10. Apply foliar B (without N) at flowering

11. Use mulch if possible

12. Consider using good compost



A o ado t ees g o like eeds – get

into them!"

• Leaves & flowers disappear from lower canopy,

due to lack of light, becoming unproductive

• A big tree expends up to 75% of its carbohydrate

just to ai tai its s affold a hes

Overgrown trees

Large tree

Productive area (green)

Unproductive area (black)

Extensive “scaffold”

Avocados need light to flower

- isolated branch in interow

Overgrown trees

• Expensive and dangerous to pick

• Less productive

• Poorer quality fruit

• Impossible to spray effectively

What you do t a t to see

Key practices for canopy management

1. Choose a tree spacing that you can manage

2. Start before orchard becomes overgrown

3. Prune every year with follow up

4. Do t hold a k! 5. Cut low

6. Selective limb removal, completely remove

one major branch per year = canopy

completely rejuvenated every 4 -5 years

7. Consider PGRs on summer flush

Crop losses of more than 50% have been

attributed to spotting bugs.

5. Spotting bug

Acknowledgements

Ruth Huwer & Craig Maddox, NSW DPI

Ian Newton & Donna Chambers, DAF Qld

Banana Spotting Bug = Amblypelta lutescens (Northern)

Fruit Spotting Bug = Amblypelta nitida (Southern)

Current situation

1. Endosulfan de-registered 2010

2. Dipterex/Lepidex (trichlorfon), Bulldock

& Suprathion (methidathion) registered

• Dipterex - important to have a low

pHwater (4 - 5) in the spray tank

• Bulldock – leads to flare up of scale

insects & mites if used too often

• Methidathion – dangerous to use and

also broad spectrum

Current recommendations

1. Ide tify hot spots a d o ito them

• Hot spots ofte fou d alo gside ati e bush along creeks lines, and high areas

• Expect influx after hot windy days

• Look on warmest/highest parts of tree

2. If possi le li it sp ayi g to hot spots

3. Spray whole orchard on calendar basis if

necessary

Current recommendations (cont.)

4. Good canopy management essential for

adequate spray cover – keep trees open

and short

5. Calibrate and test sprayer coverage

regularly

• Lure source and corflute with double-sided adhesive

• Suitable as a monitoring tool, for banana spotting bug only

• Earliest expected commercial availability of traps Oct 2016

(Gary Leeson, Organic Crop Protectants, OCP)

The banana spotting bug lure trap

Double-sided

adhesive tape

Corflute panel

Trap hedges for monitoring

Trap hedge consisting of: 1. Mock orange (Murraya paniculata) (18 months), 2 to 3 plants

2. Macadamia ternifolia (5 years), 1 to 2 plants

3. Longan (4 years), 1 plant

New insecticides

Applications submitted for registration of: • Transform® – Dow AgroSciences • Trivor® - Adama

Registrations expected 2017

These two insecticides have different modes of action. This is good and both should be used in rotation to reduce the risk of resistance developing.

Summing up . . .

key areas for productivity and quality


2. Irrigation

3. Nutrition


5. Spotting bug

6. Anthracnose management

ACKNOWLEDGEMENTS

The project has been funded by Horticulture Innovation Australia

Limited using the avocado levy and funds from the Australian

Government. The Queensland Government has also co-funded the

project through the Department of Agriculture and Fisheries.

Video and fertiliser rate worksheet for

boron now available on BPR


4. Biological control

A tiny wasp, Anastasus, that preys on the eggs of spotting bug selected as it had the most potential for mass rearing

Large numbers of Anastasus were reared and released but very hard to evaluate because:

Spotting bug host range is so wide plus most of their activity and breeding takes place outside the orchard

Spotting bug eggs are difficult to find

Impact of biological control agents including Anastatus could not be proven within this project

Large numbers of spiders considered useful

Anastasus

5. Area Wide Management

• Work could not start on this until a reliable system of monitoring was developed

• Pilot study at Alstonville, NNSW indicated that a number of strategically located trap hedges were able to be monitored and this information was used to make recommendations to local orchardists about when to spray.

3. New insecticides (cont.)

Transform® – Dow AgriSciences

• Active ingredient sulfoxaflor

• Residue trials recently completed

• Toxic to bees on direct contact

• Two week residual action

• Effective against sap feeding insects

–Robert Annetts (Dow AgriSciences)

3. New insecticides (cont.)

Trivor® - Adama • Two active ingredients:

– Acetamiprid - knockdown – Pyriproxyfen – insect growth regulator

• Residue trials completed • Efficacy trails completed • Rates to be determined • Effective against sucking insects, scales etc

- Jonathan McDonald (Adama)

The project has been funded by R&D levies from the Avocado, Macadamia, Lychee,

Papaya, Passionfruit and Custard Apple industries, with additional funding via the

Across Industry Committee and matched by the Australian Government through HAL.

NSW Department of Primary Industries (NSW DPI) and Queensland Department of

Agriculture and Fisheries (DAF) are also contributing in-kind funds to the project, and

NSW DPI is managing the project on behalf of all partners. Other project partners

include the University of Queensland, Australian Centre for International Agricultural

Research (ACIAR) and BioResources (until November 2013).

1. Development of a pheromone lure

for monitoring &/or control

On a farm at Childers last year:

• One block sprayed on a standard 21 day calendar spray schedule.

• Another block only sprayed when bug numbers caught on pheromone traps reached the threshold level.

• The same amount of damage occurred in each treatment . . . but only half the number of sprays applied in the trap block.

Case history

Multi target approach to spotting ug Ruth Huwer et al

1. Develop a pheromone lure for monitoring

&/or control

2. Develop trap crops to intercept invading

spotting bugs for monitoring &/or control

3. Investigate new insecticides

4. Investigate potential for biological control

5. Undertake a pilot study of Area Wide

Management

Project Objectives

6. Anthracnose & stem end rot

A th a ose is the ost se ious postharvest disease of avocado and a

ajo fa to o t i uti g to uality loss Anderson et al, 2004

Anthracnose management starts on the farm

Anthracnose infection

1. Spore lands on fruit

2. If fruit surface is wet (rain, dew) for just a

few hours, and temperature is above about

15°C, spores germinate & establish

i fe tio pegs i ski

3. Remain dormant, no visible signs

4. When fruit ripens the disease takes off,

rotting a hemispherical volume of flesh

that grows in size from the infection point

Leaf wetness and temperature vs

anthracnose infection

Leaf wet for 3 hours @ 25°C = 90% infection

Leaf wet for 1½ hours @ 17½°C = 20% infection

from Fitzell, Peak and Darnell (mangoes) 1984

Key practices for fruit rots

1. Canopy management for good ventilation and

spray penetration

2. Spray properly or not at all – maintain

protective film of copper fungicide on fruit as it

grows, apply every 2 to 3 weeks

3. Incorporate azoxystrobin sprays in schedule -

(a) after prolonged wet and (b) at the end of

season (very effective)

4. Choose non-Mexican rootstocks such as Velvick

Key practices for fruit rots (cont.)

5. Do t pick when it is raining &/or if fruit is wet

6. Do t snap pick:

• during a period of rainy, humid weather

• if trees have been stressed or are unhealthy

7. Keep fruit out of sun, remove field heat ASAP,

post harvest treatment with prochloraz (e.g.

Sportak®) within 24 hours, maintain cool chain,

before and after ripening, store Hass at 5°C

(other varieties at 7°C)

Acknowledgments for information,

research & updates on spotting bug

1. Ian Newton & Donna Chambers, DAF

2. Ruth Huwer & Craig Maddox, NSW DPI

3. Gary Leeson, Organic Crop Protectants

4. Robert Annetts, Dow AgriSciences

5. Jonathan McDonald, Adama

• Use 10 traps per hectare, spread about 30m

apa t, p efe a ly i k o hot spots . • Keep traps out of direct sunlight

• Monitor and replace sticky panels at least

once/fortnight (sooner if affected by sunlight,

sprays & dust)

• Renew pheromone lure every 6 weeks

• Apply insecticide if bug density reaches 0.5

bugs/trap/fortnight (5 bugs for every 10 traps)

Recommended use of pheromone trap

Other findings from project

1. Spotting bug damage worse at high

densities, in darker foliage situations

2. Beneficial insects more successful in

more open canopies (those with good

canopy management)

Possible future research

1. Identify and develop pheromones for

Fruitspotting bug (A. nitida).

2. Continue to improve the pheromone trap

3. Continue to evaluate trap hedges and

pheromone traps on commercial orchards

where both species are present

4. Continue to develop monitoring, and lure

and kill strategies using the pheromone

trap

0

5

10

15

20

25

30

35

40

45

50

Trap-Tree Non-Trap Tree 20 Traps/Ha 10 traps/Ha

% Fruit with visible BSB damage

Damage significantly higher on trap trees

(40%) compared to non-trap trees (8%)

Banana spotting bug Amblypelta lutescens

Fruitspotting bug Amblypelta nitida

Trap hedges (cont.)

• Attract both spotting bugs species

• Combination of the three different plants attract

spotting bugs for the whole season - so can be used to monitor bug numbers throughout the year

• Trap hedges work because the bugs return to areas of

earlier damage

• Monitoring allowed orchard sprays to be applied to

coincide with emerging adult populations e.g. in

NNSW 5 to 6 generations/year, therefore 5 to 6 sprays applied/year

• Used for monitoring only at this stage

Water stress e ory

Red dye in water – so more red = more water flow

Un-watered Well-watered

1. Inadequate water can cause stomata to close for 3 days.

2. Further water stress induces avocado to block xylem

ith tyloses as a su i al e ha is

DW Turner et al, 2001

managing for maximum productivity and quality

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