weed management

Pre-emergent Herbicides Preferred for Weed Management

Daniel Cooperweeds

It is best for citrus growers to implement a proactive approach to weed management. Being reactive puts producers behind the eight ball with regards to controlling certain weeds in their groves. That’s why Ramdas Kanissery, weed scientist and associate professor at the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS), is preaching the importance of pre-emergent herbicides. They …

How to Enhance Pre-emergent Herbicide Performance

Daniel CooperTip of the Week, weeds

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, …

Pointers for Better Pre-emergent Herbicide Performance

Josh McGillCitrus Expo, weeds

Ramdas Kanissery, speaking at the Citrus & Specialty Crop Expo, offered what he called an important strategy to prevent weed outbreaks in groves: “Never let ’em germinate.” Growers can keep weeds from germinating with pre-emergent herbicide programs, said the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) assistant professor of weed science. He works at the Southwest Florida …

Pointers for Pre-emergent Herbicide Use

Josh McGillHerbicides, Tip of the Week

By Ramdas Kanissery Weeds emerging in citrus rows are problematic as they compete for resources with the trees, support pests and interfere with grove operations like irrigation (Figure 1). Hence, effective strategies to control weed emergence should be in place.   Pre-emergence (or residual) herbicides are an excellent tool for the long-term suppression of weeds in tree rows. These herbicides …

horseweed

How to Manage Horseweed

Daniel Cooperweeds

University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) weed scientist Ramdas Kanissery recently shared information about management of horseweed, a common Florida citrus broadleaf weed. Kanissery is an associate professor at the Southwest Florida Research and Education Center. Following are highlights from his article in the August 2026 UF/IFAS Citrus Magazine.  Horseweed is found in citrus tree rows, …

spring

Stay Ahead of the Spring Weed Flush

Daniel CooperTip of the Week, weeds

By Ramdas Kanissery Spring is here and so are the weeds in citrus groves. Warmer temperatures and increasing soil moisture create ideal conditions for weeds. Growers often notice a rapid spring flush of weeds emerging in the tree rows and in the row middles during this time (Figure 1). If not managed early, these weeds can compete with citrus trees …

young citrus

Herbicide Safety Around Young Citrus Trees

Daniel CooperTip of the Week, weeds

By Ramdas Kanissery Young citrus trees are highly sensitive to herbicides. Even small amounts of drift onto green bark or foliage can significantly impact tree growth (Figure 1). Taking a few practical precautions during herbicide applications can help protect young trees and keep them growing strong during their early establishment years. AVOID HERBICIDE CONTACT WITH GREEN BARK The greatest risk …

brown garden snail

Best Bets for Brown Garden Snail Management

Daniel CooperCalifornia Corner, Pests

Brown garden snails (Cornu aspersum) can reach incredible population densities in California citrus orchards if left unmanaged. More than 1,000 snails per tree have been documented in some cases, according to Mark Hoddle, University of California, Riverside biological control specialist. To help growers deal with this problem, Hoddle recently participated in a Citrus Research Board webinar. He presented information on …

managing aggressive weeds

Managing Aggressive Weeds in Citrus

Daniel Cooperweeds

Ramdas Kanissery gave advice for growers in a May 20 virtual presentation about managing aggressive weeds in citrus. Kanissery is a University of Florida Institute of Food and Agricultural Sciences associate professor of horticultural sciences at the Southwest Florida Research and Education Center in Immokalee. A summary of his recommendations follows. CULTURAL PRACTICES PRACTICAL APPROACHES As part of his presentation, …

spray

Know When to Spray for Weeds

Daniel CooperTip of the Week, weeds

By Ramdas Kanissery Managing weeds in citrus groves isn’t just about what you spray; it’s about when you spray. The effectiveness of your weed control program largely depends on the growth stage of both the weeds and the citrus trees in your grove. Getting the timing right can make a big difference in how well your weed control program works …

weed management

Optimizing Weed Management in Citrus

Daniel CooperAll In For Citrus Podcast, weeds

Weeds can be a menace in Florida citrus. The state is home to diverse weed species and is the perfect environment for weeds to grow. Ramdas Kanissery, a weed scientist at the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) Southwest Florida Research and Education Center, discusses weed management challenges in the March All In For Citrus podcast. …

herbicide tolerance

Strategies for Managing Herbicide Tolerance

Daniel CooperTip of the Week, weeds

By Ramdas Kanissery Tackling herbicide tolerance in weeds is a critical aspect of effective weed control in citrus groves. It helps prevent both current and future weed management challenges. Herbicide tolerance occurs when certain weed species naturally survive and reproduce after herbicide treatment. Unlike herbicide resistance, where genetic changes allow weeds to survive and spread, herbicide tolerance doesn’t involve any …

herbicide efficiency

How to Improve Herbicide Efficiency

Daniel Cooperweeds

University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) weed scientist Ramdas Kanissery offered numerous tips and observations for improving herbicide efficiency at this spring’s Florida Citrus Growers’ Institute. They included: In addition to discussing herbicides, Kanissery reported that cover cropping, an emergent practice in Florida citrus production, may contribute to longer-term weed management in row middles. Read more …

Final Herbicide Strategy

How to Squelch Summer Weeds

Josh McGillweeds

Summer is “a field day for weeds,” Ramdas Kanissery said in a March 29 presentation about weed control for citrus. The University of Florida Institute of Food and Agricultural Sciences assistant professor provided a progressive step-by-step approach to suppressing weeds during the summer. CONTROL EXISTING WEEDSGrowers can get off to a good start by controlling existing weeds with post-emergent herbicides. …

Effects of Compost and Organic Amendments on Weed Control

Josh McGillResearch, weeds

By Ramdas Kanissery and Mahesh Bashyal Using compost and soil amendments is beneficial to Florida citrus groves. Florida soils are sandy and have a low organic matter and cation exchange capacity. Adding compost and organic amendments (e.g., humic acid) can enhance the soil’s ability to retain water and nutrients. These practices can also boost soil microbial activity and improve soil …

Post-Hurricane Weed Management

Josh McGillTip of the Week, weeds

By Ramdas Kanissery Hurricanes and the associated flooding will impact weed management in the affected season and the following years. Weeds should be effectively managed after these severe weather events as weeds may take advantage of the reduced competitiveness of recovering trees. INTENSIFY SCOUTINGA critical step in weed management after hurricanes is to scout groves and note the emergence of …

Managing Weeds in California Groves

Josh McGillCalifornia Corner, weeds

By Danielle Leal Over the years, new weeds have surfaced, and old weeds have developed resistance and become tougher to control. Crop scientists are currently researching ways to successfully manage weeds in citrus. Sonia Rios, technical development representative for Bayer Crop Science, said growers are heavily dependent on post-herbicides to help mitigate weeds. “In order to use a pre-herbicide, you …

Impact of Herbicides on Fruit Drop

Josh McGillAll In For Citrus Podcast, Fruit Drop, Herbicides

Growers know the negative impacts of any kind stress on trees infected by HLB. That raised a question: Can injury from herbicides make fruit drop worse? Ramdas Kanissery, an assistant professor of weed science with the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS), conducted a research project to help answer that question. Kanissery discusses the research in …

Diagnosing Herbicide Phytotoxicity in Citrus

Josh McGillweeds

By Ramdas Kanissery, Nimal Timilsina and Ruby Tiwari Chemical weed control is an essential component of the toolbox to keep weeds in check in citrus groves. Citrus growers primarily rely on herbicide to manage weeds due to their efficacy and cost-effectiveness. Despite their benefits, herbicides may have a wide range of unintended effects on citrus. For instance, an herbicide-related injury …

Impacts of Herbicides on Young Citrus Trees

Tacy Calliesweeds

By Ramdas Kanissery, Nirmal Timilsina and Mongi Zekri Weed control is crucial for the growth and establishment of young citrus trees. Chemical weed control with herbicides is an efficient and cost-effective method for managing weeds in newly planted groves. However, before applying herbicide products, care must be taken to avoid damaging young trees and newly planted resets. Every so often, …