Riverland Citrus Class
January 14, 2012
Robert Reifer, University of Florida and part time Riverland Nursery employee
Charlene Brogan, home gardener, reporting
About 2 dozen Alva garden club enthusiasts were entertained by Robert Reifer, life long horticulturist, accountant, and U. of Florida entomologist. His lecture at the Riverland Nursery focused on the reasons why to grow citrus, the diseases and how to manage them, fertilizing, and some cold tolerant alternatives. Following the instruction many participants were treated to a tour of the amazingly beautiful nursery.
WHY GROW YOUR OWN CITRUS?
Grocery stores don't deliver the quality of citrus grown in your back yard and according to Robert, commercial citrus are picked all at once and stored for weeks before consumers buy the fruit.
Home grown trees can be selected for the varieties you enjoy including some varieties that cannot be produced for commercial sale.
Citrus trees can become huge and offer value in the shade they produce around your home.
Property values can arguably increase with the addition of fruit producing and attractive citrus trees.
There is value in the pride a gardener earns in growing and producing citrus as we all know.
DISEASES
Two diseases, Citrus Greening (Huanglongbing) and citrus canker, are two troublesome bacteria infections in citrus trees. Treatment in the past called for the destruction of some trees, but now in the preferred treatment, trees are given extra care, fertilizer and water to optimize their health so they can at least live with the infection in production.
The Citrus Greening is spread by an insect, Asiatic Citrus Psyllad, on the new tender growth or bloom of the trees. Insecticides can help prevent infection for a longer term than organic methods but both can work.
Citrus canker is spread by wind, birds, etc., but the leaf miner provide an wound for the infection to enter. Probably all the problem citrus samples brought in by garden members had signs for leaf miner damage. The cure according to Robert is to spray the tree with liquid copper to prevent the canker. Imidacloprid is a systemic insecticide helpful in stopping various problem insects (and beneficial insects as well) including the leaf miner.
As an added note Robert explained commercial growers of tomatoes drench the soil with Imidacloprid when tomato seedlings are transplanted into the farmland. The systemic insecticide is in the plant and the tomatoes we eat.
Lady bugs eat problem insects but if purchased, count on them flying 5 miles before stopping for their meals. BT or "Thuricide" will not hurt humans but is great for cutting down on the Swallow Tail Butterfly or actually, their babies and some other relatives close and far. Some folks have had great success with Dawn dish detergent for especially aphids. Robert agreed it is effective but not long lasting and must be repeated weekly. Dormant oil spray can prevent insects and disease but again will not last very long. Robert has used a 1:9 bleach to water solution for suety mold with success, he said.
FERTILIZER
Robert cautioned all to be careful of organic fertilizer that may contain e-coli. Well composted organic fertilizer such as "Black Cow" is his recommendation.
Chemical fertilizer should be time release to prevent excess nutrients from leaching out before the plants can absorb them. A combination of compost and granular fertilizer is more efficient in holding and delivering the nutrients and by the way, preventing ground and waterway pollution.
Robert recommends fertilizing citrus March 31, summer and fall with time release fertilizer.
Fertilizer contains nitrogen, phosphorus and potassium plus 13 micro nutrients and pretty much all formulas seem to work well in Robert's experience. Keeping your citrus well fed along with correct watering is key in citrus production. Florida "sugar sand" is notoriously lacking in nutrients.
FREEZES
Think we've had some cold weather lately? Meteorologist historians know we have periodic cold snaps and will continue to experience those cold freezes from time to time. Covering frost tender plants can help but don't use plastic for a cover. Consider growing more cold tolerant varieties. Olive trees may be the future of Florida due to their cold tolerance and durability. Ask the nursery for other choices.
