By Amir Rezazadeh The giant swallowtail butterfly (Papilio cresphontes) is a beautiful insect, admired for its large wingspan and vibrant yellow and black coloration. However, for citrus growers, this butterfly is often viewed with less enthusiasm. The larvae of the giant swallowtail, commonly referred to as “orange dogs,” can cause significant damage to citrus trees. Understanding the nature of this …
Insights on Soil Amendments, Soil pH and Nutrient Availability
By Davie Kadyampakeni, Tripti Vashisth and Duplicate Sambani The University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) conducted an experiment for four and a half years to determine effects of soil amendments on soil pH. The impacts of fulvic acid, humic acid and sulfuric acid with and without elemental sulfur were compared. Canopy size, fruit yield, fruit quality, …
New HLB Publication at the Citrus & Specialty Crop Expo
By Michael E. Rogers Do you plan to attend the Citrus & Specialty Crop Expo on Aug. 21–22 at the Florida State Fairgrounds in Tampa? If so, you’ll want to stop by the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) Citrus Extension booth to pick up the latest publication on HLB management assembled by UF/IFAS citrus experts. …
Visit the UF/IFAS Citrus Extension Booth at the Citrus & Specialty Crop Expo
By Jamie D. Burrow and Michaela Ivy Since the spring, planning has been underway for the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) citrus Extension team booth to be on display at the Citrus & Specialty Crop Expo. The event is Aug. 21–22 at the Florida State Fairgrounds in Tampa. The booth will be in the same …
Using Herbicides in Hot Weather
By Ramdas Kanissery Managing weeds during the summer is crucial for Florida citrus. However, due to the high temperatures typical of Florida’s summer months, several factors must be considered when using herbicides in citrus groves during hot weather. INCREASE EFFECTIVENESS High heat and drought stress can slow plant growth and affect how herbicides move or translocate in weeds. When temperatures …
Citrus Nutrient Research Update
By Davie Kadyampakeni, Muhammad Shahid and Alisheikh Atta Current citrus nutrient guidelines are based on studies of healthy citrus trees conducted in the pre-huanglongbing (HLB) era. These guidelines may no longer be valid for the present situation where 100% of mature citrus trees in Florida are HLB-affected. Scientists at the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) …
Chlorpyrifos Update for Growers
By Brett Bultemeier and Lauren Diepenbrock The status and availability of chlorpyrifos has had numerous, and at times, confusing changes due to new rules, court rulings and Environmental Protection Agency (EPA) decisions. The point of this article is to clearly define if chlorpyrifos can be used and until what date. As always, changes are possible in the future and users …
Reduce Fruit Drop From Phytophthora-Induced Brown Rot
By Chris Oswalt During this time of the year, Florida growers should be aware of the potential for the development of citrus brown rot disease. It can infect fruit at color break. If severe, the disease can cause a significant amount of infected fruit to drop. For this reason, groves with a history of brown rot in areas that recently …
ACP Management in High-Density Plantings
By Jawwad Qureshi The Asian citrus psyllid (ACP, Figure 1) is the vector of huanglongbing (HLB) disease associated with the phloem-limited bacterium Candidatus Liberibacter asiaticus. Infected trees start to decline and produce poor-quality fruit, which drops prematurely. Consequently, citrus production has decreased dramatically since the advent of HLB in Florida in 2005. There is no cure for the disease yet. …
Cover Crops for Managing HLB
By Davie Kadyampakeni and Miurel Brewer Row middle management is a key area that can improve tree performance. Row middles encompass 80% of citrus orchards, and 70% of the root system of citrus trees was located in row middles before huanglongbing (HLB). Typically, Florida citrus growers manage row middles using physical, chemical and mowing practices, often leaving them free of …
Herbicide Application During Rainy Weather
By Ramdas Kanissery Finding the right time to apply post-emergent herbicides for controlling weeds in citrus groves is challenging in the summer months due to frequent rain. Rainy conditions delay grove maintenance, including herbicide spraying, while also impacting the effectiveness of the herbicides. Monitoring weather forecasts and identifying optimal conditions for herbicide applications can help achieve the best results. Below …
Pest Management in CUPS
By Jawwad Qureshi The Asian citrus psyllid (ACP, Figure 1) continues to feed on citrus trees infected with citrus greening and spread the disease to newly planted young trees. Therefore, it is not possible to produce a healthy citrus tree in an environment where citrus greening is endemic. Only the citrus under protective screen (CUPS, Figure 2) system allows the …
How to Prevent Fruit Splitting
By Amir Rezazadeh Citrus fruit splitting is an important problem for growers, causing frustration and economic losses. This phenomenon occurs when the rinds of citrus fruits crack open, exposing the inner pulp. Understanding the reasons behind citrus fruit splitting is crucial for growers to implement effective preventive measures. IRRIGATION PRACTICES Inconsistent watering regimes, particularly irregular watering followed by heavy irrigation, …
Managing Chilli Thrips in CUPS
Chilli thrips (Scirtothrips dorsalis) has been documented in Florida since 1991. This pest has a history of impacting ornamentals, some vegetables, grapes and berry crops. Most recently, chilli thrips has affected citrus, but only in nurseries and in citrus under protective screens (CUPS). Feeding damage includes death of young flush (Figure 1), leaf damage on expanded flush that results in …
How to Address Sectoring in Trunk-Injected Trees
By Ute Albrecht and Larissa Nunes Citrus growers who injected oxytetracycline (OTC) last year most likely experienced sectoring, which is the appearance of some portions of the canopy looking considerably healthier than the rest of the tree. RECENT RESEARCH In a recent trial in a commercial citrus grove, University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) researchers injected …
Dealing With Drought Stress
By Amir Rezazadeh Citrus trees are not immune to the challenges posed by drought stress. Drought stress occurs when a tree’s water supply falls below its demand, leading to physiological disruptions that can impair growth, development and fruit production. In the dry season, when water scarcity is a prevalent issue in Florida, understanding and managing drought stress in citrus trees …
Where to Watch for Diaprepes Root Weevil
By Larry Duncan Prior to the introduction of citrus greening disease in Florida, certain conventions applied to the occurrence and impact of diaprepes root weevil in groves across the state. The abundance and damage potential of this major pest were greatest in some Flatwoods habitats, such as parts of the inland East Coast where newly planted trees sustained major damage. …
Covering the Basics of Summer Cover Crops
By Sarah Strauss The recent rising temperatures are a reminder that summer is approaching, and the beginning of the rainy season is a great time to start planting cover crops. If you are looking for a method to invest in your soil health, cover crops are one option. By definition, cover crops are planted to improve soil health and are …
Optimizing Organic Nutrient Sources
By Davie Kadyampakeni The use of certified organic nutrient sources (manures, composts, biochar, biosolids, etc.) should be considered by Florida commercial citrus growers to improve the soil properties and long-term nutrient availability of the predominantly sandy soils. Use of the organic residues could be incorporated in the soil during tillage to plan a new grove or periodically to an existing …
Protect Trees With Particle Films
By Christopher Vincent Particle film is a useful tool to take the edge off stress to citrus trees caused by weather and HLB. University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) research over the past several years shows moderate concentrations of kaolin particle films cause trees to grow faster, suffer less water loss and keep leaves cooler, even …