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UF/IFAS Citrus Research and Education Center

UF/IFAS Citrus Research and Education Center

Citrus Health Management Areas (CHMAs)

In response to the introduction of Huanglongbing (HLB) to the Florida citrus industry, growers and researchers instituted many projects focused on sustaining the industry until a solution could be realized. The Citrus Health Management Areas (CHMA) Program was identified as an early critical aspect of HLB vector management by the National Academy of Sciences. CHMAs focused on area-wide control of the Asian citrus psyllid (ACP). Defined areas were established which grouped commercial citrus groves that are near one another. The groves contained within the boundaries of a single CHMA were to work together to control ACP with coordinated pesticide applications. Management tactics were developed with input from commercial citrus growers and were specific to each CHMA. The primary focus of each CHMA was to establish a schedule outlining when ACP control measures would take place and what insecticide mode of action would be used. There were no mandatory ACP control tactics which commercial citrus growers had to abide by. Participation in CHMA activities was voluntary.

The CHMA Program began in 2010 with a small number of defined CHMAs and grew to 55 individual CHMAs. Each CHMA acted as its own entity and devised an area-wide ACP control plan that best fit the growing conditions of the CHMA. Many CHMAs initially achieved a high level of grower participation which resulted in excellent ACP control. There were CHMAs that never gained momentum and amounted to nothing more than an imaginary set of lines on a map.

In 2017 interest in CHMAs began to decline due to multiple factors. The primary factor for dwindling CHMA participation was the continued decline in fruit yield and an increasing level of HLB infection within nearly all groves. In the best CHMAs, which sustained remarkably low ACP populations for years, the volume of fruit produced did not increase or even stabilize. Commercial growers must realize a return for every production input and most growers determined intense ACP control was not translating to improved production. Commercial growers began to focus on targeted nutrient application and root health. At the same time, and to a lesser extent, a new slate of agrochemical was brought to market and some growers shifted away from coordinated area-wide ACP control to tactics focused on mitigation of the bacteria which causes HLB.

From the beginning of the CHMA program, a robust ACP scouting regiment was maintained. Professional scouts from the United States Department of Agriculture and the Florida Department of Agriculture and Consumer Services scouted approximately 6,000 commercial citrus blocks on a 3-week cycle. The scouting method used was tap sampling. Each scouted block was tap sampled 50 times per visit. The scouting results were reported to the block owner or a designated representative. The scouting results were also used to create a spreadsheet which was published on the CHMA website. This spreadsheet was titled “The Block Specific Spreadsheet”. The scouting data was available to the public and could be viewed at any time. A block ID number was used to identify specific blocks and only the block owner knew the block Id number.

CHMA Scouting Data Cycles

The entire history of ACP scouting for the CHMA program can be found in the links below.