Organic Avocados

Mike and Cathy Crum are converting their avocado orchards near Whangarei to organic production with AsureQuality certification. Mike also manages 65 canopy ha of kiwifruit orchards in the district and they own a bee keeping business. This year they won the Hill Laboratories Harvest Award (for horticultural properties) and the Gallagher Innovation Award in the Balance Northland Farm Environment Awards.

The Crums have lived on the home Tatton Rd orchard for seven years. It is 8ha and contains 550 avocado trees, mainly 16-28 years old. They also have an Otaika Valley Rd avocado orchard of 4ha, containing 250 avocado trees of mainly 12 years old, which has been through a three-year organic conversion to achieve certification by AssureQuality.

Mike and Cathy have been involved in orcharding for 30years and have a history of embracing new technology and processes. Mike completed a Kelloggs Leadership Course through Lincoln University and won an award for his paper on the use of oils in avocado and kiwifruit orcharding and exploring pest control, fungicide activity and bud break enhancement in kiwifruit.

The Crums have 9ha under avocados, in two locations, and Mike manages 65ha of kiwifruit on 18 orchards. The success of their kiwifruit management is based on local people with very high levels of pruning expertise and a willingness to teach each other and train up new people. They are also own bee-keeping business which places hives on local orchards for pollination and produces honey. That is managed by two beekeepers on a salary plus share of profits basis. Mike is on the NZ Organic Avocado Growers Group executive which is a grouping of 68 orchards either producing organically or interested in doing so that are carrying out research, producing best practice manuals and sharing information through regular feilddays as to how to produce avocados using organic techniques. The whole fruit industry is demanding nil residues, traceability and nutrient dense fruit and organic techniques are the leading edge of that plus they have this world wide recognized marketing brand in organics which already means all those things to consumers.

Organic production of avocados is being adopted for commercial reasons, not from ideology, though the enhanced lifestyle aspects of being an organic grower and greater awareness of we are what we eat have become powerful motivators.

Mike is very aware of research he could use to increase orchard productivity or reduce costs. He has a very good knowledge of soil processes and understands the implications of changes in soil structure and health.

Kikuyu grass between avocado trees is not cut or mulched, so that it provides a good ground cover, retains moisture and builds humus. Without mowing or spraying machinery, ground compaction is minimized. A high level of soil microbial activity facilitates this breakdown.

• There is nil spraying or use of chemicals on the orchards,

• Pest levels are monitored every fortnight via Avogreen monitoring.

• Six spotted mite levels remain low after going through a population explosion in year one of conversion and defoliating most of the trees.

• Thrip levels get quite high but no damage on fruit as numbers of thrips per site are very low and don’t seem to cause damage except on fruit picked after Christmas.

• Leafroller once again get quite high on the monitoring but only small ones. Some damage but the tree seems to have a defence mechanism whereby the fruit exudes a white substance once the leafroller bites it which deters or kills it. This is visible on the fruit and also on trees if the bark is damaged. It seems much more prevalent on Otaika Valley.

Fertilisers are applied in an organic form and soil and leaf tests carried out regularly to monitor the nutrient needs. The soil is tested for trace elements and maintaining a balance is more important than supplying nutrients. No nitrogen has been applied for 5 years but nitrogen levels are fine in the leaf test.

The Otaika Valley has a history of consistent fruit production from a relatively low-cost operation. The main inputs are fertilizer and picking. All soil nutrient levels are adequate but low ie Olsen P of 8 and low potash levels compared to conventional best practice and no nitrogen is applied. Leaf test levels are in the medium range on the RJ Hill Test. There is a big emphasis on soil structure and soil life. Dry matter levels are high early in the season which helps to achieve premium prices and opens up the possibilities of being an early supplier into Asian markets and getting crop load off the trees early. We are putting a lot of the practices learnt on soil health and plant nutrition into our kiwifruit management and also achieving high dry matters with all fruit packing out in the premium Y band for taste while achieving above average production and OGR’s.

Peter Smith the beekeeper and Gabriel Torres, who co-manages the beekeeping side of the business, place hives on orchards all round Whangarei. They need to get those hives up to strength to carry out the pollination requirement, when fruit flowers can be low in nutrients. Hives are placed in avocado orchards in October/November, followed by kiwifruit orchards.

Kiwifruit winter management: Mike works with a local gang of vine pruners, some of whom have done the work for two decades and are very skilled.