By Brett Bultemeier, Mike Aerts and Lauren Diepenbrock On Dec. 28, 2023, the U.S. Court of Appeals for the Eighth Circuit revoked a previous decision related to chlorpyrifos tolerances for food. Chlorpyrifos is a broad-spectrum insecticide used in a variety of crops, including citrus. The original decision revoked all food tolerances, whereas this new ruling essentially reinstates them. This means …
Tips for Trunk Injection of Oxytetracycline
By Ute Albrecht and Ozgur Batuman Follow these important tips for proper trunk injection of oxytetracycline as a citrus therapeutic. APPLICATION TIMING INJECTION TECHNIQUE ADDITIONAL ADVICE Ute Albrecht (ualbrecht@ufl.edu) and Ozgur Batuman (obatuman@ufl.edu) are associate professors at the University of Florida Institute of Food and Agricultural Sciences Southwest Florida Research and Education Center in Immokalee. Sponsored ContentA Simpler, Safer and …
PGRs: Multipurpose Tools for Citrus Improvement
By Tripti Vashisth Canopy health of HLB-affected citrus has been directly related to disease severity, fruit drop and overall fruit production. Some success has been found with the use of certain plant growth regulators (PGRs) such as gibberellic acid (GA) and 2,4-dichlorophenoxyacetic acid (2,4-D) to achieve healthier trees with reduced fruit drop and increased production. HLB MANAGEMENT Application of these …
How to Enhance Pre-emergent Herbicide Performance
By Ramdas Kanissery and Robert Riefer Pre-emergent herbicides, also known as residual herbicides, are highly effective in the long-term suppression of weeds in citrus tree rows. These herbicides remain in the soil and prevent susceptible weeds from germinating. In order to achieve the best weed control results, pre-emergent herbicides need to stay within approximately the top 5 inches of soil, …
Planning Pointers for Insect Management
By Lauren Diepenbrock Insect and mite management is a year-round challenge in Florida citrus. With the warm climate, pests are at the ready as soon as plant resources are available to them. With knowledge of insect and mite biology in relation to tree phenology, plans can be developed to protect fruit and maintain productive citrus trees. Populations of some highly …
Irrigation Strategy to Enhance Fruit Growth and Retention
By Tripti Vashisth Huanglongbing (HLB) severity is associated with small fruit sizes and lower fruit numbers at harvest. Moreover, small fruit are more likely to drop and drop earlier during preharvest fruit drop. Unfortunately, management practices suggested to increase fruit size or reduce drop have had mixed results. So, before looking for ways to increase fruit size and number, it …
HLB-Affected Trees Use Less Water
By Davie Kadyampakeni Huanglongbing (HLB) is a citrus disease that affects the growth of the fibrous roots of citrus trees. This means that HLB-affected trees may have reduced root volume, which impacts water uptake. A greenhouse study was conducted from October 2019 to July 2021 at the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) Citrus Research and …
Mulch Suppresses Psyllids in Young Trees
By Jawwad A. Qureshi, Lauren Diepenbrock and Davie Kadyampakeni Protecting citrus trees from the Asian citrus psyllid (ACP) is critical to reducing the spread and severity of huanglongbing (HLB) disease. The frequent availability of viable shoots in young trees is attractive to psyllid colonization, feeding and oviposition events. UV-metalized reflective mulches reflect ultraviolet light, which is disturbing for some insects …
A Tool to Help Assess Tree Health
By Tripti Vashisth, Taylor Livingston and Jamie Burrow Canopy density is one of the most effective measurements to assess tree health of HLB-affected trees. Canopy density accurately distinguished between high and low fruit-producing trees in field trials, whereas CLas Ct value has been found to not be correlated with fruit yield. Many new tools such as nutrient management guidelines, plant …
Potassium and Silicon Improve Cold Hardiness
By Muhammad Shahid Winter freeze is the main threat to the emerging citrus industry in North Florida, South Georgia and Southeast Alabama. Growers use microsprinkler irrigation as a freeze-protection strategy to protect the graft union of young trees, but it is not very effective in protecting aboveground plant parts in established trees. PLANT PROTECTIONUse of stress-mitigating substances could be an …
Timing Insecticide Applications for Best Effects
By Lukasz Stelinski Here are some basic guidelines that growers can follow to manage pests successfully and economically in their groves: Take-home messages include the following: Lukasz Stelinski is a professor at the University of Florida Institute of Food and Agricultural Sciences Citrus Research and Education Center in Lake Alfred. Sponsored ContentA Simpler, Safer and More Effective Way to Fight HLBOctober …
Root Nutrient and Fertilization Guidelines for HLB-Affected Trees
By Davie Kadyampakeni, Lorenzo Rossi and Alan Wright Huanglongbing (HLB) disease lowers tree performance by reducing water and nutrient uptake as a result of root loss. HLB-affected trees have a fibrous root loss of about 30% to 80%, which increases as disease symptoms develop in the canopy. Investigating optimal nutrient concentrations in citrus roots thus improves the understanding of HLB …
Combination of Essential Oils and Kaolin to Control Psyllids
By Xavier Martini and Romain Exilien Despite intensive control efforts, the Asian citrus psyllid (ACP), the vector of Candidatus Liberibacter asiaticus, the bacteria causing citrus greening, remains the most devastating pest of citrus. The ACP typically relies on tactile, visual and odor cues to detect its host. By combining an irritant, a visual masking and a true repellent, University of Florida …
Prolong the Health of Young Citrus Trees
By Fernando Alferez, Ute Albrecht, Ozgur Batuman, Jawwad Qureshi and Saoussen Ben Abdallah Individual protective covers (IPCs), which are psyllid-exclusion mesh bags, are increasingly being adopted to efficiently protect newly planted citrus trees from huanglongbing (HLB) infection. However, IPCs typically must be removed after two to three years due to tree growth. Early evidence indicates that brassinosteroids (Brs), a relatively …
Follow Flower Bud Induction Advisories
By Tripti Vashisth Florida flower bud induction advisories for the upcoming season start on Nov. 15. These advisories will be published biweekly until March 30, 2024. The goals of flower bud advisories are to inform growers about the status of the tree in respect to floral bud induction and to predict bloom. This is critical information since the horticultural practices …
Uncovering the Cause of Greasy-Green on Grapefruit
By Megan Dewdney, Mark A. Ritenour and Liliana M. Cano In the last few years, 89% of Florida grapefruit growers have struggled with a disorder that they refer to as greasy-green, leading to losses between $20,000 to $1.7 million per year. The disorder causes the fruit to have large, diffuse green patches on the rind after degreening, making it no …
Brassinosteroids Can Improve Juice Quality and Fruit Yield
By Fernando Alferez and Divya Aryal There are some indications that brassinosteroids (Brs) may advance commercial internal maturity by almost one month in Valencia sweet orange, depending on the time of application. However, the best time of application in this variety and other sweet orange varieties like Hamlin still needs to be determined, so that this treatment can become economically …
Improve Fruit Yields and Juice Quality
By Davie Kadyampakeni and Megan Dewdney The University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) conducted a six-year project to determine if plant nutritional fertilizer sources coupled with specific crop protection chemicals help mitigate citrus diseases. This project was conducted on a 5-acre commercial citrus grove block near the Citrus Research and Education Center (CREC) in Lake Alfred. …
Increase Yield With Shade
By Christopher Vincent, Yu Wang and Nabil Killiny Mild shade reduces stress, increases growth and yield, and may improve pest management under huanglongbing (HLB). It reduces high temperature and water stresses. Shade also may reduce HLB transmission by making trees less visible to Asian citrus psyllids (ACP). Shaded trees have less ACP, and shade appears to reduce the severity of …
Trunk Injection Wounding: What You Need to Know
By Ute Albrecht and Leigh Archer Trunk injection is an alternative technique for applying crop protection materials. This technology has now been approved to deliver oxytetracycline (OTC) for huanglongbing (HLB) management in Florida. Injections cause injury, and best practices need to be established to minimize injection-induced tree damage. University of Florida Institute of Food and Agricultural Sciences researchers (UF/IFAS) injected …