plant nutrition
Using Plant Nutrition and Biostimulant Products to Continue Citrus Production in HLB-Infected Trees
• When I’ll apply ( phenological phase)
Pre - Bloom
Fruit Growth (Until Colour Change )
Fruit Growth
Post Bloom (Fruit Set)
Fruit Colouring
The concept of well-balanced plant nutrition in citrus.
By JW LEMONS | CCA, CPAg plant nutrition • What dosage I’ll apply : According citrus nutrient extraction and expected yield Pound (lb) per MT of fresh fruit Citrus N Orange 3,9 Mandarin 3,3 Lemon and Lime 3,6
P 0,4 0,3 0,3
K 5,8 4,5 3,8
Mg 0,5 0,2 0,3
Ca 1,6 1,1 1,0
S 0,3 0,2 0,2
Grapefruit
0,3
4,4
0,2
0,9
0,2
2,3
Full Bloom
Well balanced nutrition programs for citrus may improve yield, tree health, fruit quality Source: IFA - Publications - Manual : Citrus , with reference to : Koo, 1958 ; Chapman , 1968 ; Malavolta, 1989 and additional years of production in HLB-infected trees.
C
itrus huanglongbing (HLB), previously called citrus greening disease, has been covered in thousands of articles. New technology and management tools continue to be discovered. Yet we still have no definitive cure and it could be a while before we see one. New rootstocks are surfacing, and treatment techniques are having some effect on slowing this devastating disease that has destroyed huge amounts of the world’s citrus trees. As a Certified Professional Agronomist and a Certified Crop Advisor, I must prepare myself for HLB and its arrival here in the rest of California. It is currently here in one county. Many qualified scientists are approaching this menace with specific technologies, genetic modifications to trees, finding new resistant root stocks and of course trying to find something that will destroy the infections as well as a chemical or biological spray or injection that can combat and even cure the infection. Others are addressing the psyllid vector, Diaphorina citri, that spreads the disease. Spray timings, mating disruptions, netting to cover the trees and keep the insect off them are being addressed.
Nutrition for Management
One approach I have used over the years mainly in Florida and Texas is based on years of repeated trials. It calls for using balanced and adjusted plant nutrition. It is most certainly not a cure, but I have witnessed improved yield, tree health, fruit quality and additional years of production from infected trees. It takes management and a deep knowledge of your citrus trees. When are the critical 24
Progressive Crop Consultant July / August 2023