Grower Experiences

Citrus Greening

The purpose of the following information is to provide the citrus industry with grower experiences as greening continues to spread across the state. This information has been submitted by growers and is an illustration of how individuals and companies within the citrus industry are facing the challenges of citrus greening.

Evans Properties

In mid 2007, Evans Properties began to organize a strategy to scout and manage their groves for citrus greening. In October 2007, the first inspection was completed and revealed that over 50% of the 137 blocks (in 9 groves) contained greening infected trees. All of the groves were located in the Indian River region.

Overall Infection Rates

Percentage Infection Rate

Number of Blocks
No infection
16
Less than 1%
66
1% - 3%
40
4% - 5%
7
6% - 10%
5
11% - 60%
3

 

Over 85% of the individual blocks have at least one greening infected tree. However, only 1.7% of the total trees are infected with greening. Since greening symptoms sometimes do not become visible in a tree until a year or more, there are likely more greening infected trees that have not yet been discovered.

Individual Grove Infection Rates

Grove Name

Number of Trees in Grove Number of Infected Trees Percent Infection Rate
Grove #1
5,318
1,130
27.6%
Grove #2
13,660
28
0.263%
Grove #3
264,891
6,780
2.5%
Grove #4
101,337
1,395
1.3%
Grove #5
3,545 
66 
 2.05%
Grove #6
71,564
975
1.6%
Grove #7
78,583
310
0.6%
Grove #8
140,085
1,549
1.1%
Grove #9
41,978
113
0.2%
OVERALL
720,961
12,346
1.7%

 

Individual Grove Infection Rate

Infection by Total Tree Numbers

The overall picture appears that greening is in the early stages of spread in this area. Each inspection will reveal increasing numbers of additional infected trees until the psyllid and disease are under control.

Scenario: This first inspection revealed  1.7% total infection. It is recommended to scout 4 times per a year. If the company scouts 4 times the first year and finds a minimum 1.7% infection rate each time, the first full year will result in 6.8% total infection in all of their groves. If these numbers were to double each year and the company did nothing to manage the disease, then there will be no viable groves by the fifth year.

At this time, the company is making an effort to manage greening with various methods. John Crum of Evan Properties said "We wish we would have started earlier. This is not a normal problem ".

In a situation like this, it is recommended to make sure the groves are under a psyllid spray program to reduce vector populations. The need for psyllid control is the same for 1% or 50% infection rate. Until both the psyllid and the disease are under control, expect to see an increase in positive greening infected trees.


Links

 
• History • Regulations
• Transmission • Pathogen
• Alternate Hosts • Symptoms
• Nutrient Deficiencies Compared to Citrus Greening • Diagnostics
• Management • Photo Gallery
• Links • Contacts
• HLB Scion Survey