Citrus Tips

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  • Are there any “rules of thumb” to determine when citrus is ripe? Is rind colour a good indication of ripeness? According to Will Wardowski, Florida Science Source, Agricultural Books peel colour is not an indicator of maturity in citrus.  Peel colour is affected by several factors including nutrition and especially cool nights. That is why citrus from California usually has great peel colour.  Citrus from Florida may have a green peel and be very sweet. In Florida citrus can degreen on the tree in the cool winter months and regreen as the weather warms up in the spring to summer, even though the fruit continue to get sweeter.  Your test would be simply tasting sample fruit. Maturity in commercial citrus is determined by selecting representative fruit samples for testing. The tests include TSS or total soluble solids (about 85% sugar), acid, and juice content. The TSS:acid ratio is a number used to meet legal maturity standards. The University of Florida put out a 24 page book SP99 titled Quality Tests for Florida Citrus for $4.00 plus shipping.
  • Ben Waddelow foliar sprays citrus with fulvic acid to bring up the brix levels.
  • 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. 
  • Lemon trees as well as papaw develop brown bitter patches in the flesh 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.  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?
  • Carambola and Grapefruit – drug interactions  Like the grapefruit, carambola is considered to be a potent inhibitor of seven cytochrome P450 isoforms. These enzymes are significant in the first-pass elimination of many medicines, and, thus, the consumption of carambola or its juice in combination with certain medications can significantly increase their effective dosage within the body. Research into grapefruit juice has identified a number of common medications affected, including statins, which are commonly used to treat cardiovascular illness and benzodiazepines (a tranquilizer family including diazepam).  Ref: Wikipedia
  • In NZ, Tahitian Lime and Meyer Lemon are cutting grown.
  • Mineola Tangelo:  When the colour starts to fade, the acid levels have dropped and that is when to pick it. Also needs lots of Potash.  Ref:  Ian Tolley
  • Citrus info from the Philippines.   Marcotted trees tend to remain dwarf but weakly anchored, but it depends on the type of cultivar. For example, the marcotted rough lemons and Lisbon lemons could develop extensive root system as strong as grafted trees. This I know because I marcotted and grafted them and they performed the same, but not true with mandarins and oranges, the marcotted ones are poorly anchored. With Calamansi, the marcotted ones are not as good as the grafted ones, but they remain smaller. If smaller trees are good for you in wind-sheltered areas, marcotted trees could suit your needs. If you want bigger trees that are well   anchored, marcotted trees are not generally for you. One big advantage of marcotted citrus trees is that they bear quality fruits much earlier than grafted ones. Those citruses grafted unto seedling rootstocks would develop quality fruits 3 to 7 years after planting. They could produce fruits right away, but the quality won’t   be as good until the tree reaches proper size. The marcotted trees will have good quality fruits right away. This is because with grafted trees, some of the juvenility in the rootstock is passed on to the grafted cultivar. If the rootstock is very old, like a mature tree, then you get quality fruits right away, but if the rootstock is a young seedling, expect 3 years at the fastest for a nice quality fruits.   Ref:  Joe Real
  • Red Grapefruit   Was talking with the owner of the Big Orange in Gayndah and he was telling me that the Red Grapefruit like Texas Star Ruby will hang on the tree for 6 months! Then it will keep in cold storage for another 6 months!
  • Chironja   An Orangelo or orange × grapefruit cross. Seemingly spontaneous hybrid – “round to pear-shaped, necked, equal to grapefruit in size; peel a brilliant yellow, slightly adherent, easy to remove; the inner peel non-bitter; pulp yellow orange, with 9-13 segments having tender walls and much juice; the mild flavor reminiscent of both orange and grapefruit, hardly acid or bitter even when immature.”  (For the complete article see Morton, J. 1987. Orangelo. p. 160. In: Fruits of warm climates. Julia F. Morton, Miami, FL.,  22Feb 2013.)  Sheryl:  I first tasted Chironja at Ian Tolley’s place in Renmark, South Australia and thought I must have one of these – great taste.
  • The Webbing Caterpillar affects Fingerlimes and feeds on the foliage of most of the smaller-leaf species, matting the leaves together with webbing and filling it with their droppings. This can cause complete defoliation in small plants and may even cause death. The easiest and safest means of control, if the problem is found early enough, is to remove the mass of grubs, webbing and frass with the fingers and squash it. If spraying is considered necessary, a systemic spray must be used, as contact sprays are mostly ineffective.