Abstract
A discussion of the history and locations of mango growing in Australia, the current situation in regard to marketing mangoes, and considerations of how to deal with the large supply of mangoes that will be coming into the market in the next few years.

Now I will put my other hat on and talk about something which I have done a lot more of, and that is mango growing. Some of what I am discussing today has been drawn from a paper that was presented at a recent Mango International Symposium in Thailand, so I have had the permission from the authors to use their material.

If we have a look at a map of Australia, mangoes, being a tropical fruit and not native to Australia, found their way to all manner of likely and unlikely places. It is a major industry in Australia, albeit a fairly small industry on a world scale. Very, very small. But it is facing a bit of a crisis domestically, between a rock and a hard place. It is just a bit too big for purely domestic consumption, and it is not yet quite big enough for effective export. As growers, we are all struggling with that. The more traditional growing areas are in the dry tropics and the central coast of North Queensland. More recently, up on the tablelands, which is an elevated, tropical plateau in N. Queensland which has both wet tropics and dry tropics parts to it. The dry tropics part is where the mangoes are. More recently, up in the top end of the Northern Territory, where I live near Katherine, and also in the Kimberleys of Western Australia. A small industry for a long time down at Carnarvon. And for those of you who are Perthites, you are extremely fortunate, because right at the moment the only part of Australia supplying fresh mangoes is Gingin, just 80 km up the road. So you are enjoying fresh mangoes right now, but the rest of the country isn't. There is a small industry in northern NSW, and there is actually a few trees down at Sunraysia. When I lived and worked there near Mildura, we planted a trial of mangoes, all grafted material, different varieties, and we chose a site that we thought would have the least frost problem of the region. I left in '76. In '82 they had the severest frosts in 100 years, which killed all the scions to the ground level. The rootstock shot, and they came back again after that. To cut a long story short, there is one grower there that I am aware of that has a small orchard of mangoes. He would have a time-frame that would be a little earlier than Gingin, probably February-March.

The interesting thing is, that with the Australian mango industry, in the traditional growing area, there is a big disease load on the coast. Anthracnose, in particular, stem end rot plus some physiological disorders like stem end cavity are quite prolific and a regular problem on that coast line. It is a humid coast line. You can imagine the wind blowing in off the Pacific all year; there are probably only half a dozen days when it doesn't blow on that coast line. As far as the tropics are concerned, it is a humid and coolish environment. Whereas, up here in this part of the world, it is the dry tropics. If you look at the Tropic of Capricorn, anything north of that is the true tropics, and everything south of it is the subtropics or temperate. Virtually all of this part of Australia is what they call the semi-arid tropics or the dry tropics. It is characterised by a short wet season and a long dry season. In this part of the world, from Broome north and from Townsville/Bowen north, it is the semi-arid tropics, so the wet season is heavier and longer. In this part of the world, the arid tropics, where the wet seasons generally only occur in conjunction with cyclones and that sort of thing.

If you went to Port Hedland, their average rainfall is about 250 mm a year, and they only get it if the cyclones come through. This is a very regular point of access for cyclones here, just as it is over on the east coast near Townsville/Bowen/Burdekin. At Carnarvon rainfall is about 200 mm and they are entirely dependent on irrigation. Kununurra is in a valley, a jolly hot place for most of the year. I think it is 5 degrees cooler than Katherine which is 5 degrees cooler than Darwin. One time when we had our first mango research workshop in Cairns about '79, I met one of the keynote speakers from India who flew into Perth, met me in Broome and then we went to Kununurra and Darwin and flew across to Cairns in mid-to-late November. The temperature in Broome was about 33, the temperature in Kununurra was 43, the temperature in Darwin was about 32, and the temperature in Cairns was about 23 and raining. That gives you a quick synopsis on the variations across the north and the extremeness of the environment in this part of the world. But mangoes love it. Mangoes in the north is like apples in the south. So the prospects for mangoes in northern Australia are very good, they tolerate just about every soil you want to throw at them. They are only a supplementary irrigation species. They don't require long periods of irrigation: primarily from flowering to just before harvesting is the time you have to look after them to get a good crop.

If you are in a commercial growing environment, you also need to look after them through the main growing season, which is the wet season. If we have a poor wet season, we have to irrigate, because that is the time when the trees are growing, they are at their maximum photosynthesizing activity. If you don't support them with moisture, you won't build the trees up for the next crop. In a good wet season like we have just had...we probably had the best wet season in 28 years, according to one of my neighbours at Katherine. We didn't have to irrigate, basically, at all.

In these inland environments, Kununurra and Katherine being the most similar, we have low disease levels. I don't know what the cycle is yet--I have been living in that neck of the woods for 20, 25 years. Eight years in a row in the '80s were warm dry seasons, warm winters, poor flowering, magnificent bananas. Prior to that, cold, good flowering, good mangoes, poor bananas, because they get retarded by that cold spell. If you come then to the seasonal distribution, here is the distribution of the flowering times. From Darwin and Kununurra in the north, through to Gingin in the south, we can produce fruit for 7 months. With the use of varieties, late-maturing varieties, you could probably go a little later. The west coast is actually a very good mango growing area, because it has low humidity most of the year. It has a long, hot summer. When I first saw mangoes in Gingin on David Sword's place...he was the first mango grower in Gingin. He had also started the first avocados there, I think. He threw in a hundred mango trees, just for the hell of it. His first crop was '83 when I first saw them. It was January, there was a heat wave. I don't know how you bear these heat waves down here in Perth, it is so hot and dry. The fruits were all split, they were obviously under extreme water stress. But, seeing the fruits there proved the point, simple as that. Going later, I think, into mid-May, would only be upset by local circumstances in a particular year, like the onset of an especially early winter or rain. You have some disease problems down here, but nothing you can't avoid.

The major industry, again, is the dry tropics of Queensland, the Atherton around Mareeba, and increasingly around the top end, where we now have around 700 thousand trees. They did tree number estimates on aerial photographs. Probably 500 thousand aren't fruiting yet. So, in three years time, we are going to have a much larger production, and we are going to have some problems getting rid of it, if we can't start to act now.

This table gives you a little bit of estimate of production. The Burdekin and the Atherton tablelands are the two large areas. The Darwin-Katherine figure of 400 thousand is considered to be a bit of an underestimate. Related to the earlier figures about mango production in the Philippines, we are not even in the race. But we hopefully will be one day.

Our industry is firmly domestically oriented. That is a problem we have to deal with. That gives you a bit of an example of where the fruits go that are exported. Less than 10% are exported. Two big outlets are Hong Kong and Singapore. We sell into Japan, but Japan has some very restrictive access controls, predicated on quarantine issues. They don't have fruit fly, so they don't want it, fair enough. But they decided to exclude fruit that had been treated for fruit fly with the normal procedures we use in this country. Within the country we simply treat with dimethylate or penthion sprays. The Japanese don't accept that. Mangoes suffer chilling injuries below 12 or 13 degrees, so there is little scope to treat them in that way. The Japanese have a heat treatment as their preferred methodology. Heat put through as a vapour. There is only one plant in Australia that does it, at Maryville, so all the fruit has to go through there. The importer is really only interested in the top echelon of the market, to get the maximum price. Our mangoes might sell for $60 each, Australian, in Japan. If they were prepared to drop it to $30, we would have a substantial increase in demand. Hopefully, that will happen one day.

Hong Kong and Singapore are a bit of a problem, where we export what they regard as the Australian mango. Whereas, we as a company, have a brand called Mandaloo. We want to sell our Mandaloo mango as a trademark. We fairly successfully achieved that in the domestic market. We are just fiddling at the moment with small exports into Hong Kong, Singapore, the Middle East, France and a couple of other places, trying to develop an appreciation of brand and quality. It takes time and it is not exactly easy.

The varieties that we grow now: Kensington is the main variety, has been ever since the start, really. It is the one that the Australian market generally wants. The R2E2 was selected as a seedling from a seeding population planted out of a range of specific varieties that were pollinated, probably, by Kensington, by the QDPI, in Eyre. R2E2 came out to be the best of those. It is a very large fruit, 700-800 grams, very good quality, good yielding characteristics, but to some extent, a bit big. The Chinese love it. The Singaporeans love it. The demand for the price and the volume is yet to be really established. It is only the beginnings of that variety.

Irwin is one of the so-called American varieties. The Americans collected genetic material from the tropical world 100 years ago, set it all up in an arboretum in Florida, and then selected out of those seedling populations, and named about a dozen varieties. Irwins and Haydens, in Kununurra, particularly, and a little bit of Kent, which is a parent of R2E2, are grown. Keat, I think, is a second generation seedling, is grown around Mareeba in N. Queensland. Our production has been Kensington Pride and we are trying to establish that as a variety on the world market, against the Philippines' Carabao and the Indians' Alphonse, the Mexicans' and Brazilians' Tommy Atkins, which looks great and tastes absolutely terrible. We think we have a great future, but it is hard work to actually get the demand.

It is interesting, if you look at it in a physiological way. The late Elias Charcot (?), a researcher at Darwin doing photosynthetic work before he died and who had been in the chair of horticulture in all India before he came over, found that the Kensington, in terms of annual photosynthetic capacity, the photosynthetic rate dropped from 100% to about 10% in the dry season. That, very largely, is the reason why we have a tendency for that variety to be biennial. In our part of the world, it is even more than biennial. You might get two or three years of fairly poor cropping before you get another 'on' year. By grafting the trees, we can overcome that to a fair extent. More and more, the new orchards going in are grafted. Not so much on the Queensland coast...the problem is less extreme there, again because it is cooler. Whereas the Irwin will drop only to about 90% of its wet season maximum. So it is more reliable, it partitions its nutrient flow to flowering very regularly. When the crop is on, the current photosynthetates from the leaf area are able to feed that crop. With Kensingtons, in most of the fruit development phase, it is the stored carbohydrate sources that are feeding that fruit. So then you have a big problem to get the stores back up in the following wet season.

We irrigate as much as we can. The typical irrigation is undertree sprinklers. In some parts on the Ord on the black soils, they can flood. The problem is the vapour pressure deficit across the top of the canopy. It is an extremely low, 25-30% humidity. Any amount of irrigation doesn't quite achieve what a humid environment will. Those figures are diminished, in other words the reduction in photosynthesis is diminished when you go to the Queensland coast because of the more favourable climate.

The essence of growing mangoes in cooler regions is that you keep outside the frost line. Where it is frosty, you can plant on a slope which allows the cold air to drain away, so that at least during the critical times of flowering it doesn't burn the crop off, then you are in the ball game. Indeed, even if you have a problem with frost, because of the coldness of this southern environment, you actually get flower buds initiated which don't come out, normally. Mangoes are terminal flowering, so the terminal bud flowers, and if that is burned off by the frost, another lateral bud down there can come out, as long as another frost doesn't come along and burn that off. That happened one year on the trees at Gingin on trees that were about 7 or 8 years old. He lost that first flowering altogether, and then three weeks later, the flowering happened again, and by then the frost period was past. He got a crop. So, it is all about site selection, and it is all about choosing a north-facing slope in this latitude, so you get plenty of winter sun. Another problem in this latitude is whether you get enough good climatic conditions to get a vegetative flush after harvest. (Tape ends)