Hi everyone! I have searched through the threads for a solution to my problem and have not found a ready answer. I have a Eureka lemon tree on dwarf stock. The tree has responded well to regular fertilizer and produced robust leaf growth. This season has been very poor. The tree is not producing fruit. I have seen one flower all summer. The leaves are struggling with one or more problems. The first symptom is a white 'fluffy' like deposit on the leaves. It is getting thick in some places. The second symptom is a black powdery like substance on the leaves. Third, several leaves are curling or severly distorted in appearance. The leaf clusters are deformed in their appearance. I have been dealing with a significant amount of argentine ants in my yard this year. I have had to chase them from this lemon tree on several occasions with success. I have sprayed the tree with rose spray. I use rose spray because it has been very mild in my previous use. In other words, it doesn't kill the tree. It is obviously not working very well. I will be able to provide some photos on another day if necessary but I hope the savy readers of the citrus threads will be able to direct me to a commercial product to get rid of this heavily infested problem. Thank you! Over run in San Diego coastal
The white substance could be scale, or whiteflies--the ants suggest aphids as well--the black is sooty mold growing on the secretions of the insect pest. Horticultural Oil spray-- 1% -- will handle all of the above except ants--for them you can stop them at the bottom with tanglefoot or vaseline over a layer of plastic. Don't spray the oil when temp is above 85 F (early morning is best). The distorted leaves are probably leaf miners--oil spray new growth every few days--or use spinosad.
Thank you for your diagnosis and reply. What is horticultural oil spray? Do you have a brand/product name? How long till I see results? Thanks, Mouse
There are numerous oil sprays on the market--Ultrafine, Volck--they are all distillation fractions for mineral oil and work by smothering the insect pest. Soap is another option--a couple TBS of liquid dishwashing soap in a gallon of water--it also works by drowning the insects, but does not work as well as the oil and does not work at all for leaf miners. Just remember, don't spray the oil when it is over 85--it can damage the tree and cause it to loose leaves.
Ultra Fine Oil is sold and all Home DepotGarden departments, and most garden centers. Besides retarding the Citrus Leaf Miners from laying eggs on a newly spray leaf, Ultra fine will control most every insect/bug your citrus tree will ever incur. Ultra Fine is completely 100 percent non toxic. - Millet
A few weeks back I was told that a new product was being tested in some of the southern counties of the U.S. Suppose to work better than oils and soaps. Dale
I went to our Home Depot. The only oil product was a concentrate of Volstok or a name similar to that. Is this the correct product for my application? Thanks
That is probably Volck oil--yes that is one of the horticultural oils that is commonly used. Spray a 1% solution when temperature is below 85--late evening or early morning--spray the underside of leaves to kill pest such as scale and aphids. To discourage leaf miners--spray new growth every few days until the leaves mature.
