Mike Roberts

Improving Root Health and Citrus Tree Productivity

It’s no understatement that citrus greening has had a significant negative impact on the Florida citrus industry. Many growers are looking for ways to increase the productivity of citrus trees, replanting new citrus trees when production levels for citrus greening-infected trees fall below a profitable level. Citrus greening seriously compromises the roots of citrus trees, causing root loss that affects water and nutrient uptake and eventually killing the tree. One method of lengthening citrus tree productivity—improving root health—was shared by UF/IFAS plant pathologist Evan Johnson at a past OJ Break webinar. Johnson shared tips for Florida growers on improving root health to lengthen citrus tree productivity in the face of citrus greening.

Improving Root Health

Johnson maintained that citrus greening causes 30 percent to 50 percent root loss in the early stages of the disease and 70 percent to 80 percent root loss as the disease advances. Furthermore, the damage caused to citrus trees’ fibrous roots exacerbates the damage caused by other root pathogens and pests, like phytophthora. Citrus greening is an eventual death sentence to citrus trees and their production levels, but focusing on root health can help keep citrus trees productive for a longer amount of time.

While there are yet no management options for preventing root loss caused by citrus greening, Johnson shared options for extending the productivity of citrus trees through improved root health. Recommendations include:

  • Modifying fertilizer application to match the roots’ limited uptake capacity. 
  • Irrigating often and applying fertilizer in smaller, more frequent doses to help roots in the uptake of both and prevent further damage to existing roots.
  • Johnson advised that growers “avoid using root growth stimulating treatments,” as they are counterproductive.
  • Avoid root stress by keeping the soil pH level at 6.5.
  • Choosing rootstocks for replantings that fare well under HLB stress and are well-suited to the individual grove’s conditions.

Johnson shared that growers who have followed the above guidelines have reported a significant increase in root mass in their groves.

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