Tips from George Allen

  • Mancozeb   A useful tip that came from one of our members was that spraying with Mancozeb after physical damage was effective in enabling the repair of plants and fruit. The use of copper sprays tends to accentuate the damage due to the restricting effect it puts on cell division. Funguses find it hard to multiply in the presence of copper at higher rates, but so do plant cells. Mancozeb on the other hand consists of Zinc and Manganese. Zinc is beneficial to reproduction and growth and Manganese is important in plant health. Mancozeb has been passed for use on a lot of crops in Queensland, so before using it, check if it has been passed for the plant and use as per instructions. Maybe Zinc Sulphate used as a trace element spray would also help in these circumstances. Should be a great Mango season with this dry weather, no anthracnose. If it does rain when the flowers are on don’t forget to spray. Mancozeb is good on flowers. If some of your mango trees flower very early, cold damage to the embryos will cause a lot of them to abort and fall off. Just remember that you will have to supply water and nutrient to fill the fruit from here on. If you get rain then a spray of copper-oxychloride will help defend against fungal problems, and still be reasonably environmentally friendly.
  • One of our members reports that the use of CaB on early flowering fruit trees has dramatically increased fruit set. This product consists of Calcium sucrose 10.0% & boric acid 1.0% in a liquid form that appears to be rapidly taken up by the trees
  • Our Flat Seedless Persimmon has just finished producing this year thanks to an early spray of Confidor just after fruit set to control the Fruit Spotting Bug so we had an excellent crop. I used nylon stockings to keep fruit fly and birds from them. The stocking leg was able to be wrapped over the fruit 3 or 4 layers thick. The bats still were able to suck/eat 3 of the fruit through the stockings but this was stopped by hanging wind chimes and tinsel strings in the tree. We still had landings after that but a step ladder left erect close to the tree seemed to keep them right away. Next year I’ll try motion sensor lights; they work well except windy days set them off.
  • Flying Fox  My favorite store, ALDI, had rechargeable spotlights on sale at $24; 55watt halogen searchlights, the bats were like stunned mullets and the toads become totally paralyzed. The trees look very different in its light and what was very noticeable was that fruit and flowers really stand out. It’s a great way to find those hard to see fruit. It was the first time I’ve been able to see how nimble bats are through the trees once they recover. If you’ve got a strong spotlight give it a go as you will be surprised how different it all looks.
  • Pitomba  Since using the Sprayphos 620 the Pitomba have taken on a lush vigorous look, the good growth is remarkable for shrubs that have a reputation for such slow growth. I suspect that they have a constant battle with Phytophthora normally. The tangy apricot tasting fruit is worth growing. If anybody else has noticed good results with Sprayphos, can you let me know. I’ve mentioned many times I’ve seen very good responses in growth on a variety of fruit trees to its use. The Pitombas increase in growth was amazing. A lot of trees suffer from this disease and show these symptoms in the form of crippled growth, tip die back & also leaf tip burn, of course some plants inevitably die, such as Avocados and Jarrah Eucalyptus marginata (a Myrtaceae as is Pitomba)
  • On Quantum there was a segment on Phytophthora in rain forests in North Queensland and the conclusion was that the disease was present only in disturbed soil that became alkaline. Maybe by maintaining an acid soil we might be able to control it in our trees. 
  • Non fruiting trees   I visited one of our member’s properties and although nearly all of the trees looked great and grew well, a lot of them produced very few fruit. Some such as the Black Sapote and Grumichama had heavy crops; I was asked if I knew the solution. I have been told many times that zinc is critical for cell division and flowering, but although it might help I didn’t believe this was the main issue. I did notice that the Jackfruit were malformed which is an indication of poor pollination. I remember that Peter Young had told us all many years ago that boron increased seed set, so I suggested that increasing the amount available to the plants by ground application or by foliar spraying should be effective. Boron is toxic to plants at quite low amounts so its application needs to be carefully controlled. The soil application rate using Borax is about 2 grams per square metre. Custard apples when deficient can be given up to 5 g/m2 , though care must be taken to ensure that the spreading is even. Below are quotes from Plant Nutrient Disorders 2 Tropical Fruit and Nut Crops, which we used to have in the library.
    “The fruit of boron-deficient Pawpaw are deformed and bumpy due to the irregular fertilisation and development of seeds within the fruit. Ripening is uneven and the developing fruit secrete pinkish white to brown latex. Heavy premature shedding of deficient male tree flowers and impaired pollen tube development can lead to poor set in the fruit-bearing female trees.”
    “Deficient avocado trees produce small misshapen fruit, usually twisted to one side giving them a dumpy, lop-sided and bulbous shape. An indented blemish sometimes appears on the concave side of these fruit.”
  • Lemon trees develop brown bitter patches in the flesh and pawpaw  are bitter and not sweet. These symptoms in fruit show that when the deficiencies are very severe the affect on seed set and calcium utilisation is very advanced by this point. Leaf analysis is the only accurate way of knowing what is happening but it is prohibitively expensive for hobby growers so observation of the symptoms is for us the second best solution. I will copy a guide to visual analysis of leaf symptoms for the next newsletter, but it takes experience to identify the problems, especially when there is more than one deficiency affecting the plant. It would be useful if someone could write a program that would diagnose the problems when the observed affects were inputted. It would be a basic tool for small gardeners, any volunteers?
    Phytophthora   This is a solution to a wide spread infection of many plants that often cripples the growth and production of them and for some such as Avocados results in death. Australian state governments are recommending its use to save many species of trees from extinction; WA and SA are particularly hard hit.
  • I was very interested in the biodynamic farming practices at Philippe dufaud's place, particularly the drum of liquid compost being stirred. I was given a bottle of this compost tea from the barrel and this now forms the basis of a microbial/fungal tea mix I have brewing in a 65 litre bin. I did some research on the net & with what I thought I knew put together a compost tea brewing kit. A 65 litre bin, aquarium air pump, plastic tube & an aerator stone, this is now blowing bubbles through my tea. I’ve added composted cow manure, seaweed liquid, fish emulsion, compost & molasses plus some mulched Pitaya (which I had noticed was a good compost exhilarator) A witches brew that will be hard to check for bacterial & fungal action. On looking at the web again, I realized that this was big business & equipment could be very expensive & checks need to be carried out by a good laboratory. After much reading I suspect that given the right conditions your soils will be colonized naturally, a well composted, mineralized & mulched garden probably will over time end up with the right balance of flora & fauna - that’s if you don’t kill it by our normally heavy handedness, the use of pesticides, fungicides, chemical fertilizers that burn & digging & solarising the soil. I didn’t realize just how complex soils are; one author was saying there were 300 named species of earth worms in Australia & he believed there were at least twice that many. In a plot at Samford they found 23 species, the weight of bacteria in a hectare of soil is about the same as 2 cows, there are vast amounts of fungus & other living creatures that live in balance & it is they that we owe the fertility of the soil to, & also our own existence. Think twice about how you use your soil; it is the foundation to our life & much abused by our ignorance & arrogance.    George Allen