Specifications

a) Operator requirements

b) Owner-Operator requirements

c) Monitor requirements

d) Trainer requirements

e) Auditing programme

1. Sample Area

    Combined Sample Area

2. Sample Plan

    2.1 - Orchard Map

    2.2 - Sampling Method

    2.3 - Sample Size

    2.4 - Monitoring Schedule

2.4.1 - AvoGreen Lite

3. Monitoring by Pest

    3.1 - Leafrollers

    3.2 - Greenhouse Thrips

    3.3 - Six-Spotted Mite

    3.4 - Armoured Scale Insects

AvoGreen Manual

Overview of the AvoGreen^® Programme

What is AvoGreen^®?

AvoGreen^® is an approach to avocado production that aims to increase the profitability and improve the sustainability of avocado growers by ensuring better control decisions and by focusing on the market desire for safe and healthy fruit grown with minimal impact on the environment and the community.  Consumers and the wider community often consider pesticides to be very harmful.  However pesticides are also potent management tools for Growers and the industry needs to preserve their use.  Public concerns need to be addressed and pesticides need to be used carefully and prudently.  Demonstrating that as an industry we extract maximum benefit from each and every spray applied would help meet both of these aims.

 

AvoGreen^® uses the principles of Integrated Pest Management (IPM) to ensure pesticides are used only when needed.  This approach serves to justify the continued use of pesticides by growers while ensuring use is minimised and justifiable.  Monitoring is the key method used worldwide to adapt pest control on an orchard to the actual pest situation found on that orchard.  Action thresholds are an integral part of ensuring effective use, keeping pest populations below levels that cause economic loss.  The AvoGreen^® programme has to be rigorous and auditable to provide the necessary quality and safety assurances to our customers.

 

The AvoGreen^® programme is owned and operated by the AGA for the overall good of the industry.  The Board is responsible for the system and how it is managed.  AvoGreen^® was launched to the industry in 2000 and since then has been tested and proven to be a successful pest management tool, even under high pest pressure.  The system is reviewed annually and improved as circumstances change. Comments from growers and other industry players have been and will continue to be sought as part of each review.

 

Growers become AvoGreen^® compliant once they have a monitoring agreement with an accredited AvoGreen^® Operator and a Sample Plan (or Plans) for the orchard has been drawn up.  Note that growers do not have to be registered or become approved unless they personally are undertaking the monitoring. 

 

Benefits of the AvoGreen^® programme.

The AvoGreen^® programme helps growers by:

• Providing a point of difference that can be used to effectively market our fruit now and in the future as global competition rises in our markets.
• Helping deliver fruit that is acceptable to all markets.
• Saving the use of a spray when none is needed, potentially reducing costs.
• Improved export pack out at an industry wide level leading to less fruit on the local market. For those growers whose rejects are predominantly caused by pest damage, an improved pack out is anticipated.
• Providing an IPM system that is cost effective and controlled by our industry.

 

Definition of IPM

Integrated Pest Management (IPM) is the management of pests (including diseases) using a combination of methods to reduce the dependence on pesticide sprays and so minimise adverse effects on people and the environment.  There is an emphasis on biological control and economic action thresholds.

The basic concepts underlying an IPM programme include:

• Prevention – knowledge of potential problems.
• Observation – monitoring.
• Intervention – when necessary and targeted with minimal side-effects.

 

The Structure of the AvoGreen^® Programme

Using IPM principles, the AIC has developed a Standard to define the requirements of the AvoGreen^® Programme for both growers and customers.  This Standard is met by complying with the AvoGreen^® Monitoring Protocols and the AvoGreen^® Specifications which sets the requirements for each of the key roles in the system.

 

Key Roles

Key roles in the AvoGreen^® Programme are:

• AvoGreen^® Operator: a business that supplies a monitoring service to growers.
• AvoGreen^® Owner-Operator: a grower who monitors their own orchard.
• AvoGreen^® Monitor: an individual employed by an Operator (or an Owner-Operator) who monitors orchards under the AvoGreen^® requirements.
• AvoGreen^® Trainer: an individual accredited by the AIC to train people to become AvoGreen^® Monitors.

Because these roles are critical, those undertaking them have to be accredited with the AIC.

 

AvoGreen^® Grower

 

How do I qualify as AvoGreen^® compliant?

The critical step that makes you compliant as a grower is to undertake to have your orchard monitored according to a Sample Plan (or Plans) developed for your orchard.  You do not have to register unless you intend to become an Owner-Operator or a Monitor. 

 

Each Grower needs to choose whether their orchard will be monitored:

• by contracting an accredited Operator to undertake the monitoring,
• OR by becoming an Owner-Operator and monitoring their own orchard.

 

Having an accredited Operator monitor your orchard

 

If you do not want to monitor your orchard yourself, you can contract the services of an AvoGreen^® Operator.  You and the Operator need a signed agreement covering how the monitoring will be done, including an agreed Sample Plan (or Plans if there is more than one Sample Area), which becomes the basis for determining compliance.

 

The Sample Plan specifies:

• the orchard(s) (PPIN) concerned, which will be monitored as one or more Sample Areas;
• the number of trees to be monitored, which depends on the size of each Sample Area;
• the type of monitoring, using Marked Trees or  Repeated Random selection:
• the Schedule of monitoring, including a defined start date;
• whether scale is to be monitored or not; and
• whether a monitoring round can be terminated once the threshold of the target pest(s) is exceeded.

 

You should annually review the above details with your Operator to ensure that you are getting the best performance from your monitoring service.

 

Auditing

Monitoring results

Your Operator will provide monitoring results that note whether or not any action threshold has been exceeded.  If a threshold is exceeded, you as the grower decide whether to spray or not, and the choice of spray material.  You can delegate this responsibility provided you do so in writing to the person concerned, and as long as that person holds the appropriate qualifications (i.e. GROWSAFE^® certificate).

 

If a threshold is exceeded but you believe the pest is localised, you may choose to spray only part of the relevant Sample Area. You can choose not to spray even if the threshold has been exceeded.

 

Cost of monitoring

The cost that the Operator charges for their service is part of your individual contractual arrangement with your Operator.

 

 

Becoming an Owner-Operator

 

An AvoGreen^® Owner-Operator undertakes monitoring on an orchard that they own or manage.  The monitor can be the orchard owner/lessee or an employee. 

 

An Owner-Operator may monitor their own orchard(s) (however many PPINs they may own) plus two other grower’s PPINs or one other grower’s PPIN plus one Combined Sample Area. A Combined Sample Area is a group of up to 5 small orchards in the one locality that together form a single Sample Area (see AvoGreen^® Owner-Operator requirements under the AvoGreen^® Specifications).  One of the growers involved may also become the Owner-Operator for the group.

 

If you want to become an Owner-Operator, you need to complete an Expression of Interest form and return it to the AIC. If the role of Monitor is being delegated to a permanent employee, the Owner or Manager registers as the Owner-Operator and specifies who will be the Monitor.

 

Training

The person undertaking the monitoring must have the appropriate accreditation or undergo training with an accredited AvoGreen^® Trainer. Monitoring is described in AvoGreen^® Monitoring on the website: www.nzavocado.co.nz.

 

For more details on the requirements for an Owner-Operator, see the relevant section under the AvoGreen^® Specifications.

 

 

AvoGreen^® Standard

 

AvoGreen^® is a responsible and auditable production system that assures safe fruit for customers.

An operational standard for AvoGreen^® has been developed for growers and customers using IPM principles.

 

I.            AvoGreen^® Compliance

For an avocado crop to comply as AvoGreen^®:

 

1.       Each spray should be supported by pest monitoring results.  In certain cases alternative reasons can be used, see section II below, ‘Justifying a spray other than by monitoring’).

2.       Pest monitoring has to be carried out by an accredited AvoGreen^® Monitor.
See AvoGreen^® Specifications for the relevant requirements.

 

3.       All agrichemicals¹ used must be approved and applied at no more than the maximum rate given in the AIC Avocado Quality Manual and on the product label. 

 

4.       All agrichemical applications used in producing an avocado crop must be recorded in the electronic spray diary for that PPIN and the diary verified by the Packhouse before the crop is picked.

 

5.       The appropriate Pre-Harvest Interval given in the AIC Avocado Quality Manual for each agrichemical and market must be met.

 

6.       All persons spraying agrichemicals within an orchard in the AvoGreen^® programme must have a current GROWSAFE certificate.

 

7.       Spray rigs must be well maintained (a legal requirement under the HSNO Act) and should be regularly calibrated and used as set up.

 

¹ The term "agrichemicals" includes all chemicals used in producing an avocado crop excluding fertilisers and spray adjuvants, unless these are being used as pesticides.  Approved agrichemicals are registered pesticides with a label claim for use on avocados.

 

NON-COMPLIANT CROP

In general, non-compliant crop will not be eligible to be exported.  Crops for which AvoGreen^® compliance has lapsed may still be accepted for export at the discretion of the AIC and after a review of each case.

 

II.            Justifying a spray other than by monitoring

Monitoring is the most important and most common way in which a spray application can be justified. 

 

Below are specific examples of when a spray is allowed without monitoring.  Further situations will be investigated during the implementation phase for universal AvoGreen^®.

 

a)       When the threshold for greenhouse thrips is exceeded, two sprays are allowed without monitoring for the second spray provided the second spray is applied between 14 and 30 days after the first (between 15 – 21 days is ideal).

 

b)       When armoured scales are found at harvest, growers can use their reject analysis data showing armoured scales were present to ensure that at least one spray with a label claim against armoured scales is applied the following season provided no such spray has already been used against any other pest.

 

c)       One leafroller spray is allowed after flowering and before the end of January because this is a critical timing.

 

 

III.            Other AvoGreen^® Considerations

Although not an obligatory part of the current AvoGreen^® programme, the following aspects are good practice and fit with IPM principles:

 

• Coverage - Ensure all sprays applied result in maximum impact by checking that the coverage achieved matches the target area for the intended pest or disease.

 

• Chemical choice - Where possible use sprays that are selective and have no or little impact on beneficial insects in preference to broad-spectrum pesticides.  See selectivity grouping included as Appendix 1.  However choice is at the grower’s discretion.  Note that where sprays are needed against more than one pest, market forces and common sense favour the use of a single agrichemical.  Market MRLs restrict the choices available.

 

• Water blasting - Where possible, clean fruit at packing with high-pressure water blasting.  Use information from the last harvest, from pickers or from a bin inspection at the packhouse to determine the risk of contamination by pests or by other insects and mites.  Water blasting not only reduces contamination but also can lower residue levels.

 

• Bee Safety - Protect bees and other pollinators by only spraying during flowering when it is essential, and following “bee-friendly” practices particularly when hives are present in your own orchard or any nearby property.  These include mowing the sward before spraying if it contains any flowers.  Observe any restrictions given on the label of pesticides that may harm bees.

 

 

IV.            AvoGreen^® Specifications

 

AvoGreen^® Standard consists of the following:

 

a)        AvoGreen^® Operator Requirements;

b)       AvoGreen^® Owner–Operator Requirements;

c)        AvoGreen^® Monitor Requirements;

d)       AvoGreen^® Trainer Requirements;

e)        AvoGreen^® Auditing Programme.

 

a)      AvoGreen^® Operator Requirements

An AvoGreen^® Operator is a business which provides monitoring services to avocado growers in compliance with AvoGreen^® specifications. Operators employ or contract accredited AvoGreen^® Monitors.

 

Businesses wanting to become accredited AvoGreen^® Operators need to complete an application form and return it to the AIC. Before undertaking monitoring, Monitors employed by the Operator need to be registered with the AIC and appropriately accredited or trained by an accredited AvoGreen^® Trainer.

Operators need to: 

·         Register with the AIC in a contractual agreement;

·         Have a documented system;

·         Complete an Operator - Grower Agreement with each Grower;

·         Agree on the number of  Sample Areas per orchard with each Grower;

·         Have a Sample Plan for each Sample Area used (see AvoGreen^® Monitoring Protocols on the website: www.nzavocado.co.nz).  The Sample Plan is the basis for determining compliance, and includes:

a)       An Orchard map;

b)       Sampling method;

c)       Sample size;

d)       Monitoring schedule;

e)       Whether scale is to be monitored;

f)        Whether monitoring can stop once the threshold is exceeded.

       A template of a Sample Plan is available on www.nzavocado.co.nz

·          A register of all Monitors used, including records of their training, eyesight test and accreditation;

·         An internal audit program;

There should be a meeting of the Grower with the Operator and/or Monitor before the start of each season to review the Sample Plan with regard to pest levels and damage found at harvest.

 

b)      AvoGreen^® Owner-Operator Requirements

An AvoGreen^® Owner-Operator undertakes monitoring as in the AvoGreen^® Monitoring Protocols on an orchard that they own or manage.  The monitor can be the orchard owner/lessee or an employee. 

                                

An Owner–Operator may monitor their own orchards (however many PPINs they may own) plus two other grower’s PPINs or one other grower’s PPIN plus one Combined Sample Area. A Combined Sample Area is a group of up to 5 small orchards in the one locality that together form a single Sample Area (see Combined Sample Area under the Sample Area section of the AvoGreen^® Monitoring Protocols).  One of the growers involved may also become the Owner–Operator for the group.

 

Growers wishing to become an Owner–Operator need to complete an Expression of Interest form and return it to the AIC (form available on www.nzavocado.co.nz). If the role of Monitor is being delegated to a permanent employee, the Owner or Manager registers as the Owner–Operator and specifies who the Monitor will be.

 

All Owner-Operators need to: 

·         Register with the AIC using an AvoGreen^® licensing agreement;

·         Have a documented system as detailed below;

·         Verify ongoing compliance,  and;

·         Pay an initial fee of $100 (+GST) every five years.

The documented system is made up of:

·         A Sample Plan for each Sample Area, including:

a)       An orchard map;

b)       Sampling method;

c)       Sample size;

d)       Monitoring schedule;

e)       Whether scale is to be monitored;

f)        Whether monitoring can stop once the threshold is exceeded.

For more details on the Sample Plan, see the AvoGreen^® Monitoring Protocols. These protocols and a template of a Sample Plan are available on www.nzavocado.co.nz.

·         A register of all Monitors used, including records of their training and eyesight test.

·         Pay for any audits required by the AIC using the AIC appointed auditor.
 

Training

The Owner-Operator or person nominated as Monitor must be accredited or undergo training from an accredited AvoGreen^® Trainer.  Monitoring requirements are detailed in the AvoGreen^® Monitoring Protocols, which is found on the website: www.nzavocado.co.nz

 

The initial fee for becoming an Owner-Operator includes the accreditation of one monitor, either the employee nominated as Monitor or the Owner-Operator. The AIC will provide this training at no extra cost (excluding travel costs etc), provided attendance is at a specified AIC training course – training outside of these specified sessions through a commercial provider will not be funded.

 

c)      AvoGreen^® Monitor Requirements

An AvoGreen^® Monitor is a suitably trained and accredited person who undertakes  monitoring  using the AvoGreen^® Monitoring Protocols.

 

Monitors must:

• Either be an Owner-Operator or be employed by either an Owner-Operator or an Operator.
  
• Have acceptable eyesight – this is ascertained by taking an AvoGreen^® eyesight form to an Optometrist and having an eyesight test  (form available on: www.nzavocado.co.nz).
  
• Complete an application form and return it to the AIC with a $25 (+GST) payment (form available on: www.nzavocado.co.nz).
    
• Following a successful eyesight test and application, the monitor will need to undergo the appropriate training and pass the test from an AIC accredited AvoGreen^® Trainer. 
  
• Have at least one year’s experience of pest monitoring or be undergoing the AIC in field training course.

Although the basic monitoring protocols have remained the same through the current revision of AvoGreen^®, there have been a number of small changes. Currently accredited Monitors should familiarise themselves with these by studying the AvoGreen^® Monitoring Protocols on www.nzavocado.co.nz. 

d)      AvoGreen^® Trainer Requirements

An AvoGreen^® Trainer must have a sound knowledge of the pests of avocados and their identification as well as previous experience in AvoGreen^® Monitoring.

 

Consistency and standard of  Monitor training will be maintained by:

 

• Using a set basic course (AIC Basic Training Module);
• Comparing test results from different Trainers;
• Having assessors attending some courses.

 

Trainers need to:

• Attend and pass one of the AIC courses for  Trainers;
• Be assessed in the delivery of 2 free training sessions to monitors as specified by the AIC;
• Have access to a data projector, or devise an alternative way to show the powerpoint training module for the basic course (e.g. networked computers), as well as access to a suitable venue;
• Be able to locate suitable sites with pests present in order to run practical field training sessions;
• Limit training attendance to a maximum of 20 people per session;
• Test monitors using an AIC test and notify individual test results to the AIC. 

 

e)      AvoGreen^® Auditing Programme

The AIC will appoint an independent verification agency to audit compliance of Operators, Monitors and Growers with the AvoGreen^® specification and protocols. The costs of these audits will be borne by the AIC except for the Operator audits which will be at the expense of the Operator.

 

By registering with the AIC each entity (Operator, Owner-Operator, Monitors and Growers) agree to submit to and co-operate with any audits as required.

 

All Operators will be audited on an annual basis. Owner-Operators, Monitors and Growers will be audited on a random basis with a fixed proportion being audited each year.

 

 

V.            AvoGreen^® Monitoring Protocols

1.      Sample Area

An orchard can be monitored as a single unit or subdivided into several Sample Areas.  The number of Sample Areas has to be specified for each orchard when monitoring is first established, and reviewed at the start of monitoring each season.   

 

Subdivision is recommended if there are big differences between different parts of an orchard (varying tree size, variety or tree management) that are considered likely to affect the pest risk in that area, or how the grower responds to a pest find.  Most orchards are likely to use a single Sample Area.

 

The aim is for all trees in the Sample Area to be as similar as is practical in order to target the response to where it is most effective, and to ensure that sampling can be minimised. Large orchards may group blocks under different management practices, such as time of intended harvest. If the differences are significant, each such group is better treated as a separate Sample Area.

 

Factors to consider in determining the number of Sample Areas to use are:

• Historical pest levels and how these are spread across the orchard,
• Sources of pest invasion e.g., adjacent vegetation including unsprayed or neglected areas,
• Type, and location of shelter belts,
• The need to obtain a representative sample for each Sample Area,
• Cost.

 

It is important that the sample trees do truly represent the Sample Area.

• Avoid selecting corner trees as these can be atypical,
• If a selected tree is obviously atypical, e.g. a sick or replacement tree, substitute it,
• Don’t select pollinisers to be sample trees.
• As far as is possible ensure representation reflects likely sources of pest invasion, e.g. from adjacent vegetation.
• If necessary subdivide the area to ensure representation.

 

The appropriate number of sample trees for that size Sample Area is selected at random across the area.

 

Combined Sample Area

A group of up to five small orchards in the one locality may join together to become a single Sample Area provided they are sufficiently similar in tree size and management and have a combined total productive area of less than five hectares.  This provision is to allow small, potentially uneconomic units to combine for monitoring.  They can then contract for monitoring with an Operator or a local Owner-Operator, who may be one of them.  As a guide, orchards within 1 km of a central point could be considered for combining.  At least one tree must be sampled on each orchard in each round.

 

2.      Sample Plan

Once the Sample Area (s) for an orchard has been defined, a Sample Plan for each is developed.  In the majority of orchards a single Sample Area will suffice and have only one Sample Plan.

 A Sample Plan is a written plan that includes the following:

 

-          Orchard map;

-          Sampling method;

-          Sample size;

-          Monitoring schedule;

-          Whether scale is to be monitored;

-          Whether monitoring can stop once the threshold is exceeded.

 A template of a Sample Plan is given in Appendix 2 and on the website.   If an orchard has several Sampling Areas, each would have a separate Sample Plan, but with some common features, such as a single orchard map.

 

2.1- Orchard Map

An Orchard Map is a key part of the Sampling Plan for each orchard showing all orchard blocks, other significant landmarks and the AvoGreen^® Sample Areas.  The Grower, the Monitor and the Operator should each have a copy of the orchard map, which should be available for audit.

 

Each map must show:

• Name of orchard owner or manager;
• Contact phone/fax number;
• Orchard address, including number, road, and P-PIN;
• Orchard boundaries;
• Boundaries of avocado blocks, and block name or number;
• Access routes;
• Buildings and other physical landmarks;
• The number of avocado trees per block;
• Plantings in other blocks, e.g. kiwifruit, citrus;
• Boundary and a unique identifier of each Sampling Area;
• If sampling is from Marked Trees, the approximate position of each should be shown;
• Any hazards.

 

2.2- Sampling Method

Sampling can be done by:

• EITHER repeatedly visiting marked trees selected initially at random - the marked trees method, 
• OR by repeatedly taking a random sample of trees - the repeated random method.

 

The marked trees method is considered simpler to operate, while the repeated random fits better with statistical theory on sampling.  Some growers believe that the marked trees method gives a better measure of how effective a spray applied between two consecutive samplings has been.  Although this may apply with the more numerous pest populations such as six-spotted mite and greenhouse thrips, the method may overstate the effectiveness with more individual pests such as leafrollers. 

 

a)       Marked Trees

Within each Sample Area identify and mark the randomly selected trees using a readily identifiable and durable marker e.g. coloured tape or paint.  Monitoring can be carried out on these trees for up to three seasons before a new set of marked trees is selected.  Changing more frequently is better. When selecting trees to be marked, the grower or orchard manager should accompany the monitor. Marked trees should be indicated on the orchard map

b)       Repeated Random Sampling

True random sampling each round is time consuming.  Selecting trees using a ‘zig-zag’ or ‘W’ path through the Sample Area is an acceptable compromise.  Start the zig-zag on each visit at a different part of the Sample Area and vary the distance between trees sampled in a random manner.  On each visit trees are sampled without regard as to whether or not they have been sampled on previous visits.

c)       Sites to Monitor

Sites to monitor should be taken from around the circumference of each tree and at a range of heights within reach from the ground:

• A fruit site is a pair of touching fruit: use five sites per tree.  Fruit monitoring is preferred for leafrollers (LRs) and is the only way to sample greenhouse thrips (GHT).  If fruit are not in contact with one another, fruit that are touching leaves or branches may be used as substitutes.  If all fruit are hanging freely, sample a nearby tree with touching fruit instead. If there is no near tree with fruit hanging individually, for LRs use shoot samples while for GHT use three individual fruit as a fruit site.
• A shoot site for leafrollers is all the leaves and the tip of the terminal 15cm of an actively growing shoot: use ten sites per tree.  When only some fruit sites are available, use two shoot sites for each fruit site that has to be replaced.
• A leaf site for six-spotted mite is a freshly mature (i.e. newly full sized) leaf: use ten sites per tree.

 

Sampling from the upper canopy can be done instead of ground sampling, but needs the written mutual agreement of the Grower and their Operator or Monitor. In the case of Owner-Operators sampling from the upper canopy needs to be included in the sampling plan. The OSH implications mean that this practice is more suited to Owner-Operators.  All other aspects of tree selection and sampling remain the same when monitoring sites in the upper canopy.

 

 

2.3- Sample Size

AvoGreen^® monitors 5 fruit sites (and 10 leaf sites) on each tree sampled on each occasion in the Sampling Schedule.

 

The number of trees monitored is based on the size of the Sample Area.

 

Sample Areas larger than 5 ha are not recommended. If a grower chooses to use very large Sample Areas they must be extremely careful that these are sufficiently uniform, and that it is not being done simply to reduce the amount of sampling.

 

 

Sample Area	Number of trees monitored
less than 50 trees	5
less than 3.5 ha	10
3.5 – 10 ha	30
greater than 10 ha	50

 

The areas above are for blocks less headland space.

 

Sample trees are selected randomly from throughout the entire Sample Area that they represent.  A stratified sample plan could also be used.

 

The numbers of trees in the table above gives the basic or minimum number of samples.  If any pest is of particular concern, then taking more samples will more accurately determine its abundance.  It is far better to do this by selecting more trees for sampling rather than by examining more sites per tree. The action threshold remains the same even if the sample size is increased.

 

     

2.4- Monitoring Schedule

A Monitoring Schedule outlines the plan of monitoring rounds to be undertaken throughout the season.

 

How often monitoring is done depends on the risk of damage which in turn depends on pest pressure and how quickly this can change.  As pest pressure varies from orchard to orchard, the best schedule for any particular orchard should be developed specifically for that orchard.

 

Populations of greenhouse thrips (GHT) change more rapidly than other avocado pest, especially when conditions favour the thrips.  This is why during the high risk period for thrips, monitoring should be no more than 2 weeks apart, while it can remain at 3-week intervals for leafrollers (LRs), even at times of high risk for LRs.

 

Flowering and harvest periods also affect what can be done about pests and hence whether a grower monitors or not at such times.  However a Quarantine Monitoring for LRs should be carried out shortly before each harvest.

 

 

Note. A Monitoring Schedule is a flexible planning tool and not a rigid timetable – things will change as the season progresses and the Schedule altered accordingly.

The main three approaches on how to define a Monitoring Schedule are indicated below. Full details on how to use these approaches are given in Appendix 3:  “Determining the Best Monitoring Schedule”.

 

1.  The “Pest up” approach. 

In this approach anticipated critical periods (flowering and harvesting) are noted on a calendar and monitoring planned around these targeted at GHT, LRs and 6SM in that order and taking into account pest biology and past experience with each pest on that particular orchard. 

 

This method has the advantage of clearly showing the planned monitoring rounds and whether there are gaps (see example in Appendix 3).  

 

2.  The “Periods of Risk” approach.

This is the method previously used in AvoGreen.   Key periods of risk and a suggested sampling frequency are defined for each individual pest without actually drawing up a proposed schedule. The risk periods for each pest will vary from one orchard to the next depending on location and pest pressure. To use this approach properly would require adjusting the periods to reflect what actually happens on the particular orchard for which the Monitoring Schedule is being devised.

 

3.  From a spray programme.

It is possible to derive a Monitoring Schedule based on a past spray programme, however this approach risks missing the ideal timing for sprays, and is most unlikely to increase packouts.  Be very cautious if considering this method, and plan a monitoring round at least one interval before a spray was applied to increase the possibility of improving timing. 

 

Caution.

Reducing the number of monitoring rounds increases the risk that a pest will cause damage before it is detected.  Careful use of past and current information from your orchard minimises the risk but does not eliminate it.  Also note that damage at harvest may indicate a critical timing was missed, but only if all sprays against that pest achieved a successful kill. 

   

2.4.1- AvoGreen^® Lite

In seasons with little or no fruit, there is little incentive to monitor or to spray.  Returns per unit area are lower, while the cost of a spray remains constant.  This raises the level of percentage damage at which a spray is worthwhile, i.e. the economic threshold.  As well a lighter crop gives proportionally more fruit that hang singly, which reduces the potential for damage by leafrollers or greenhouse thrips as these pests prefer to occupy where fruit touch.

 

In such circumstances AvoGreen^® compliance is maintained provided every spray applied is justified by a

monitoring result or other recognised justification.  This approach leaves the decision process of balancing the actual crop load against the pest risk in the hands of the grower, who is in the best position to quantify the relevant factors.

 

Any reduction in monitoring increases the risk that sprays will not be optimally timed, and that damage will occur that could have been prevented.   Reducing monitoring should only be done after carefully considering the periods of maximum risk of damage on your orchard, as the tactic of only monitoring when you intend to spray is a very high risk approach that is likely to fail to deliver any benefit.  

 

 

 

3.      Monitoring by Pest

3.1- Leafrollers

Leafroller caterpillars are the most common and damaging pests of avocado crops in New Zealand. A number of species are involved, with the main ones being the brown-headed leafroller Ctenopseustis obliquana, the black-lyre leafroller Cnephasia jactatana and light brown apple moth Epiphyas postvittana.

 

When to sample for leafroller caterpillars:

Fruit damage can occur at any time of year, but is more common soon after fruit set once fruit grow large enough to contact other fruit and so provide the sites where caterpillars prefer to feed. In some areas caterpillars will be found around the stem on young, marble-sized fruit before this, and for early fruit monitoring you can use three nearby individual fruit of this size as a single fruit site.

 

Leafrollers are also important quarantine pests so that a Quarantine Monitoring of fruit close to harvest is highly recommended.

 

The Monitoring Schedules given as examples indicate what is best practice for orchards with low to moderate pest pressure, but more monitoring should be undertaken where there is a higher risk of leafroller damage. Monitoring within 2 weeks of applying a leafroller spray is not recommended except to check the effectiveness of the spray application.

 

How to sample for leafroller caterpillars:

Leafroller caterpillars feed on both fruit and leaves, but fruit sampling better reflects the damage potential for the crop, and shoot sampling should only be used when touching fruit are not available.

 

Fruit sampling:

• A fruit site is a pair of touching fruit;
• If touching pairs are not present, one option is to use 3 individual fruit as a fruit site;
• Check 5 fruit sites per sample tree;
• Inspect for the presence of live caterpillars. Even if more than one caterpillar is found in a site, record it as one live infestation.

• Record clearly fresh damage as if you had found a live caterpillar because the caterpillar can be lost during the inspection.

 

Shoot sampling:

• A shoot sample is all the leaves and the tip on the terminal 15 cm of an actively growing shoot.
• Check 10 shoot samples per sample tree;
• Examine all the leaves on the terminal 15 cm, including the shoot tip, the leaves of which should be prised apart to find any young caterpillars sheltering inside.
• If a live leafroller is found, record the shoot as infested and move on to the next site on the same tree. Do not record leaf damage where no caterpillar is seen. If more than one caterpillar is found on one shoot, record it only as one infested site.

 

Shoot samples and 3 individual fruit are options particularly for early in the season when the previous crop has been harvested and before the new crop has grown and provided fruit to fruit contacts.

 

When examining both fruit and shoot sites in the one monitoring round, record the results separately.  Use 2 shoot samples for every 1 fruit site that has to be replaced.  The combined percentage infestation is calculated using:

 

(2 x (total infested fruit sites)) + (total infested shoot sites) x 100

10 x number of trees monitored

 

                                             

Action Threshold Level

A spray application is recommended when more than 2% of sites are infested.

 

Quarantine Monitoring

Sample fruit as above for caterpillars but also record any leafroller egg rafts found on the fruit.

 

Action Threshold level for Quarantine sampling

If any caterpillars or eggs are found discuss what options are available with your packhouse.

 

NB:  One leafroller spray may be applied without monitoring between the end of flowering and the end of January due to this being a critical timing. Consider the export market MRLs when choosing what pesticide to use at this time of the year.

 

3.2- Greenhouse Thrips (Heliothrips haemorrhoidalis)

 

How and when to sample for greenhouse thrips

From January until April monitor about fortnightly.  Sample five fruit sites per tree on the specified number of trees.  As a fruit site, use two fruit in contact as first choice; if not enough fruit pairs are available use fruit in contact with a branch or a leaf: and if all fruit are small and hanging free use three individual fruit as one fruit site.

 

Carefully examine each fruit around the point of contact, stopping for that site as soon as GHT are found.

 

Record whether each site was infested or not.

 

Action Threshold Level

A spray is recommended if more than 2 % of sites are infested

 

• Two sprays two-three weeks apart are recommended. 
• The second spray does not require separate monitoring as justification provided it is applied between 14 and 30 days after the first (between 15 – 21 days is ideal).
• A grower may always choose not to spray once a threshold is exceeded (for example if conditions for the pest are not favourable), but in such circumstances and with GHT in particular  they should then monitor more frequently, even weekly, in case numbers increase rapidly.

 

 

3.3- Six-Spotted Mite (Eotetranychus sexmaculatus)

Six-spotted mite (6SM) causes leaf drop.  The mites are on the lower leaf surfaces, where they cause a characteristic purplish discolouration.  Damage starts next to the main veins where side veins branch.  However the presence of damage is not sufficient by itself to determine whether a spray is needed because  frequently there is only old damage with no live mites present.  6SM are more of a problem in the Far North and Whangarei than in the Bay of Plenty, although induced leaf drop has been reported from all regions.

  

When to sample for 6SM

6SM acts as an extra stress that may trigger premature defoliation rather than always and automatically causing leaf drop.  The most critical time to detect and control 6SM is just before flowering, because during flowering trees are under great stress, mites can be numerous and control options are limited by the presence of bees for pollination.  Mite numbers often crash naturally to low levels in mid-summer without intervention.

 

Mites are most common from September to early December, but have been found at other times.

 

How to sample for 6SM

Choose leaves that have recently matured, i.e. are just fully expanded.  This focuses on current infestations and avoids some leaves that have only old damage.  Pick ten such leaves per sample tree, one leaf from each of ten sites around the tree, or two from each of five sites.

 

6SM can be patchily distributed across an orchard block.

 

Examine the underside of each leaf carefully to determine whether or not live 6SM are present.  Leaves can be littered with bodies of mites, infertile eggs and other debris.  Note that tydeid mites are also common, and can be mistaken for 6SM although tydeids are actually harmless.  Some magnification is essential when monitoring for 6SM, and a microscope is better than a hand lens to minimise the risk of missing infestations or misidentifying what is present.

 

Score each leaf for live mites (ignoring eggs) to give an abundance index:

 

 

 

 

Action Threshold levels

Thresholds for 6SM have not been established by trials in New Zealand.  The following are suggested because low numbers do not warrant spraying:

• More than 25 % of leaves with Low abundance,  OR
• More than 10 % of leaves with Higher abundance.

 

However a spray is at the grower’s discretion once 6SM are detected.  A higher threshold should be used at times other than just before or during flowering.

 

 

3.4- Armoured Scale Insects

The main armoured scale pest on avocados is latania scale, Hemiberlesia lataniae, but the closely related greedy scale, H. rapax, may also be found.

 

Changes in the quarantine status of latania scale in 2005 reduced armoured scales to a minor pest for almost all markets.  Monitoring for armoured scales is now optional. 

Using harvest data

Instead of monitoring, growers can use reject analyses from their packhouse showing that armoured scales were found to ensure that at least one spray with a label claim against armoured scales is applied during the following season.  If no such spray has already been used against any other pest before this time,  the harvest detection of scales serves to justify one application.

  

How and when to monitor for armoured scales:

Monitoring is best done in January and/or April, with a sample in October if the pest is abundant.

 

• EITHER  Sample fruit:
  • Examine the five pairs of touching fruit per tree used as a leafroller sample for scale.
  • Carefully lift the scale cap and determine whether it is live or not using a hand-lens.
    • Live - the body under the cap is yellow or pale and plump with fluid.
    • Dead - the body will be brown, either bloated with liquid or dried out and dark.
  • Score each fruit of the pair separately as being infested with live scales or not.

 

• OR  Sample leaves:
  • Sample ten mature leaves per tree from inside the canopy at a height of 1.5 - 2.0m.
  • Place in a bag labelled with the grower’s name, Sample Area, tree number, and date picked. 
  • Keep the bag in the shade until sampling is completed.  At base, store in a cool place until examined, but do not refrigerate.
  • Using a microscope or mag-lamp, examine both top and lower surface of each leaf for settled scales.
  • Determine whether each scale is alive or dead as above.
  • Record the numbers of leaves infested with live scale.

 

Action Threshold Levels

A spray application is recommended if:

• EITHER more than  4% of leaves are infested with live scale;
• OR more than 6% of fruit are infested with live scale.