Posts Tagged ‘ Asian greens ’

Issue 82: IPM Practices for Outdoor Growers

May/June -2005
Author: Michael O’Dea

Following a cancer scare, MICHAEL O’DEA moved to south-east Queensland where he established an eco-friendly, outdoor hydroponic facility, adopting IPM practices and biocontrols to grow pesticide-free lettuce, herbs and Asian greens for the health food market. His story first appeared in the November/December 2004 issue of Practical Hydroponics & Greenhouses. Here, the grower gives us an update.

Well, 10 months later;how did we go? What were our goals and did we achieve most of them? To answer the first question, it is necessary to review our objectives, which are best summarised in an article authored by Dr Porter and published in Practical Hydroponics & Greenhouses (Impact of Global Market Drivers, Sept/Oct 2004). This article highlighted a number of issues that will influence future food production practices worldwide.

In his article, Dr Porter said that in the future, food will be produced using very different technologies than are used today. “Public concern over food safety (particularly chemical residues) and environmental flow of pesticides and nitrates into the environment are having a huge impact on crop production systems,” he said.

Dr Porter pointed to water conservation and water use efficiency as other major problems facing the world and, of course, is a major issue here in Australia. He also points to energy audits on production and anti-GMO sentiment as market drivers that will force growers to conform to stringent quality assurance guidelines to meet food and environmental safety standards;standards that are already embraced by many northern European countries. “In the next decade, ‘clean and green’ will mean zero pesticide residues in food and will require proof that crop production practices do no harm to the ecosystem, otherwise growers will face the prospect of environmental tariffs,” Dr Porter said.

We figured that people have to eat and they will want nutritious, pesticide-free food. We attended a nearby Saturday morning grower market on the Gold Coast for three weeks and we sold out of our product very quickly. The consumer reaction to the pesticide-free, no soil organisms, no herbicide concept was really positive, and it gave me a chance to explain to customers that we were not organic, but a viable alternative.

Unfortunately, the other growers didn’t see it that way and complained we had taken a lot of business away from them (which was true). The market organisers decided to listen to these growers;not the customers. We were not invited back.

Marketing-wise, a lot of what we did was guesswork. We knew we could grow a good product because we had undertaken formal training at Burnley College, Victoria, and had 20 years experience as commercial growers. What we did not have was knowledge of the varieties the market wanted, which meant we wasted time growing the wrong varieties. It also took some time to grow the right crop to suit the climate. We are still learning. As Rick Donnan has said many times in his column, Reader Inquiries, hydroponic technology represents only 10% of skills required to grow a marketable crop;the other 90% is based on knowing your crop and having the growing skills.

We now deal with a wholesaler at Rocklea Market, Brisbane, and a supermarket chain. We also supply restaurants direct. In a way, that suits me fine as we no longer spend all day at a market, which can be time-consuming.

The majority of hydroponic growers know how efficient hydroponic systems are in terms of water and fertiliser use. In our case, we use 700 litres of water to produce $100 worth of produce as opposed to the scandalous 750, 000 litres of water to produce $100 worth of rice. As well as the usual fertilisers, we add in our own organic ‘herbs and spices’ to get optimum crop health, and we do not dump water every so often.

We use town water which is chlorinated. Our water quality is atrocious and hovers around EC 0. 8-1. 2 – the water contains a lot of dissolved solids. In spite of the handicaps, we still produce an excellent product.

Our water and fertiliser costs are small. There is also no run-off into the environment – we recycle the water. If we need to bleed solution, we irrigate fruit trees and potted herbs.

Hydroponic and greenhouse growers have many advantages over traditional soil growers. I can’t see why hydroponic growers need GMOs, because we do not need to weed, and we can spray on friendly Bacillus thuringiensis (Bt) to aid in controlling a number of harmful insects, if we need to. We do not need to use ozone depleting methyl bromide – our production level per sqm is far higher than can be achieved by growing in the ground. We use very little in the way of pesticides, and hydroponic growers are allowed organic inputs, such as Eco Oil and soap sprays to counter insect pests and diseases. We grow our crop in polyethylene channels;we do not use PVC.

In Europe, especially in Scandinavia, many crops are grown hydroponically without the use of pesticides using biocontrols to keep pest problems in check. Water and nutrients are also recycled.

Our objective at the Squeaky Green farm is to avoid the use of toxic chemicals on the vegetables we grow to give consumers a pesticide-free product. To achieve this, we use biocontrols to keep most of our pests under control. We release hypoaspis predatory mites every fortnight to keep fungus gnats and thrips under control. We were given some rove beetles ages ago by Biological Services in Loxton, SA, to control fungus gnat, thrips and shore flies, and we still see these beetles in the media when we are working around our crop. We keep a constant look out for pests in the crop and eveyone who works at Squeaky Green monitors the crop for pests and beneficials during their work routines. A daily record is kept of the status of the crop, where beneficials are released, and where pests are found.

Because we use friendly bugs, they put a constraint on what we can use in the way of sprays. If we have to use sprays, then they have to be biorationales. We did start off by using pyrethrums, which are an allowed organic input, but we found it tends to knock off beneficials as well as insect pests.

We have found we get a very good influx of aphidius parasitic wasps to control aphids (Myzus persicae). We also get a variety of ladybird (Hippodamia convergens) that feed on aphids. We are exploring the possibilities of growing banker plants to keep a population of parasitic wasps on hand.

We have found ants are our biggest problem – the ants farm the aphids for their honeydew secretions. We use boric acid and sugar as a bait, and greasing around the legs of the tables tends to keep the numbers down.

As far as the aphids are concerned, if we keep a careful eye on our Asian veggies, we know where the aphids are and we can get rid of them by spraying them with Eco Oil. I only use a small pack to spot spray hot spots. We did get some large brown aphids (Uroleucon sonchi) on our lettuce in the winter months, but they seemed to disappear by spring.

We also release green lacewings fortnightly and they do a great job of cleaning up anything they can get their fangs into; including my arm.

Micheal and Jant O’Dea inspect the crop for pest.

I have seen a few whitefly on our sticky traps, but numbers have never increased, so maybe the lacewings are eating any nymphs. We have a resident population of brown frogs in our flood and drain trays.

I think our worst problem is going to be Rutherglen bugs (Nysus vinitor) in late spring/early summer. We struggled with them in 2004. Many conventional growers have the same problem. Complete exclusion is possible but it restricts the air flow around the crop too much. Has anyone got any help on this topic? I have talked to a number of entomologists in the IPM area and they all tell me Nysus vinitor is very hard to control biologically, as are mirrids, another sucking insect. I do have some strategies in mind, such as growing a trap crop which I can use to attract the bugs away from our veggies.

The Vortex Bug Bin light trap is most effective inside the netting

Lepidopterous caterpillar pests are not a problem for us as we use netting, and we also use a Vortex Bug Bin light trap. We started off by putting the light trap inside the netting, but we have since moved the trap just outside the netting. This device has proved invaluable to us because it traps so many bugs. I do not know all the bugs it traps but I did have a talk to Dr Richard Drew at Griffith University, Qld, who has worked with the light trap. He is enthusiastic about its ability to trap bugs of the crop-eating kind.

This innovative product has enormous potential in many areas of crop production including vegetables, turf, macadamias, lychees, cotton, and anywhere where the Coleoptera beetle and Lepidoptera caterpillar are a problem for growers. Redlands nursery just outside Brisbane has used the Vortex light trap for four years and they say they could not do without it now.

According to evaluation tests carried out by CSIRO Entomology at the Australian Cotton Research Institute, Narrabri, NSW, the overall results of the Vortex light trap were positive. The data shows that Helicoverpa caterpillar densities were substantially reduced within and around the array of Vortex light traps. It must be stressed that this work only involved two fields over part of a single season. Such unreplicated experiments require cautious interpretation because other (unknown) factors could contribute to the differences shown. The CSIRO study showed promising results, but it also highlights the need for careful evaluation in the future.

The Squeaky Green farm specalises in pesticide-free Asian herbs and lettuce.

‘Clean and green’ will mean zero pesticides in fresh produce with no harm to the environment, and some kind of proof to show that these standards are achieved. Labels on food to indicate that it is produced in a sustainable way is one way to demonstrate proof. For example, in Belgium, over 2,000 growers market under the Flandria label, where the motto is ‘Quality Vegetables – Approved by Nature’. In Australia, Freshcare does address grower accreditation to some extent.

So far, we are not really emphasising the fact that the Squeaky Green farm is pesticide free. I need more time to find out how far into the season we can go with no pesticides. We have had to use azoxistrobin to treat small amounts of septoria and pythium.

We use a bio-friendly trichoderma fungi in the water to suppress disease organisms and it appears to work really well. I have a microscope and I can diagnose the most common fungal pathogens by the shape of the spores. On the subject of diagnosis, I use a 12x magnification lens, which I bought off my optician, to identify insect pests and diseases.

We had a touch of albugo (also known as white rust) on the Asian greens. It only appeared on one plant variety and we have stopped growing this crop until the weather conditions are no longer conducive to the disease.

Our quality has been excellent all the way through the season and we have gained sales by having a better quality product than the ground growers. By the end of the year, in time for summer, we will have 5,000 sq. metres of production area.

What we do need is like-minded growers to try and achieve ecologically sustainable standards and to put together a label that consumers will recognise.

For soil growers, there are some encouraging technologies being used to conserve water and nutrients. Dr Richard Stirzaker from the CSIRO has invented a soil probe which enables ground growers to monitor nutrient usage where water is in the soil profile. The device is called FULL STOP and can be used to give precise water and nutrient doses. Mulch techniques have also been developed to avoid disturbing soil profiles. By growing a cover crop, the resulting problems of bare earth can be avoided.

It is up to us as growers to start to implement sustainable growing systems, and here at Squeaky Green, we have a lot of answers to the problems we have experienced so far. It would be good to get some kind of Internet chat room going for likeminded growers.

I would like to thank my wife Janet and daughter Nicola for helping to achieve our goals. Without their eagle eyes, we would not be able to be Squeaky Green.

For further information contact Michael O’Dea at email: