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  • Hop Stunt Viroid Infecting Citrus Trees in Georgia

    File photo shows citrus tree.

    According to UGA Extension IPM blog, hop stunt viroid has been discovered in Georgia.

    Citrus production in Georgia is rapidly increasing each year. There are citrus plantings in backyards, production, and plant nurseries within at least 32 GA counties. The growth of citrus in Georgia is only expected to increase over time. However, there are some threats to expansion.

    Citrus has many viroids, a tiny virus-like pathogen, that harm the plants throughout the world, but few have been found on citrus within Georgia. Hop stunt viroid (HSVd) is one of several viroids known to infect citrus. This viroid has been reported within Arizona, California, Florida, Texas, Washington state, and throughout the world. HSVd is typically transferred from plant to plant on contaminated grafting and pruning tools. HSVd can infect many different plants, including hops, grapevines and citrus. A large host range helps the pathogen spread.

    In the United States, HSVd has been found on many different grapefruit, orange and tangelo varieties. Symptoms include discolored and gumming inner bark, pitting (small holes) in stems, bark splitting (coming apart) and stunted growth. There are typically not leaf or fruit symptoms. Some citrus varieties are resistant to HSVd, but others, including tangerines and their hybrids will show damage. There are also different types of HSVd, called cachexia and non-cachexia variants. “Cachexia” means severe chronic illness, so the cachexia variants are much more dangerous and the noncachexia variants typically do not cause damage.

    In May and June of 2020, leaf samples were collected and tested for HSVd. The samples were collected from 12 different citrus plants from two nurseries located in southern Georgia. The cultivars sampled included Citrus reticulata ‘Dekopon’ and ‘Owari’ as well as Citrus unshiu ‘Miho Wase’ and ‘Brown Select’. The sampled trees looked relatively healthy with little or no signs of damage, but were selected for routine screening. Three to five leaves were taken per plant from throughout the leaf canopy.

    Small pieces of leaves were cut and used for RNA extraction. Reverse transcription-polymerase chain reaction (RT-PCR) and sequencing was used to verify infection with HSVd. Recombinase-polymerase-amplification (RPA) technology was also used to further confirm positive samples as HSVd. Nine samples were negative for HSVd, but the other three were positive. The positive samples were all taken from Citrus reticulata ‘Dekopon’. The sequencing results revealed that the positive samples were non-cachexia HSVd variants.

    This is the first time HSVd has been found in Georgia. This and other viroids could pose a threat to the growing citrus industry within Georgia in susceptible varieties.

    Currently, only noncachexia variants have been found, but nursery stock infected with this viroid should still be destroyed to prevent spread. Georgia nursery producers and citrus growers should take appropriate precautions to prevent the spread of this viroid disease. Ensure that proper sanitization is used on citrus grafting and pruning tools. Further research is needed to determine the distribution of HSVd and its potential to impact commercial citrus production in Georgia.

  • Whiteflies Flaring Up in Florida Vegetables

    File photo shows whitefly adults feeding on a yellow squash seedling.

    According to the South Florida Vegetable Pest and Disease Hotline, whiteflies are flaring up in tomatoes and watermelons in Southwest Florida. In the Central Florida area, growers indicate that whiteflies are present in tomatoes low numbers, although some of the early plantings were hit hard by whiteflies.

    Tomato Yellow Leaf Curl Virus pressure remains less than 1% but it is present in nearly every planting.

    Growers in Homestead, Florida indicate that whitefly numbers are present in oriental vegetables.

    Management of whiteflies later in the season depends on early suppression of whitefly populations. Growers need to be aggressive with systemic materials like Venom, Sivanto Prime and Verimark, early in the season.

    Proper scouting remains a viable management tactic for controlling silverleaf whitefly. University of Florida entomologists have established thresholds that have been successful for tomato producers.

    For more whitefly management tips, see click here.  

  • Fungicide Resistance a Growing Problem in Strawberries

    Fungicide resistance in strawberries is a major problem, says University of Georgia Cooperative Extension plant pathologist Phil Brannen. He encourages producers to help researchers understand which fungicides are still active and provide protection against diseases like anthracnose and botrytis.

    “(Fungicide resistance) has really come to the forefront in the last few years. In the last two or three years, we have seen a lot issues, particularly with anthracnose. Prior to that, we may have had some breakdown but not nearly as much,” Brannen said. “With those fungicides in general across a lot of commodities, (they) are now starting to lose their activity and it just finally happened for us in strawberries. They’ve had issues with that in Florida for now several years also; South Carolina, we all know this happens when you spray that fungicide class; over time, they eventually break down and quit working. We’ve got to get better resistance, and we’re probably seeing more of that in other areas, too; other fungicides, particularly on botrytis.

    “When trying to control botrytis, we have quite a few of fungicides that no longer work. I just encourage producers to make sure they test. If they have the opportunity, they can actually send off their pathogens on the strawberries and they can be tested for which fungicides are still active. That’s helpful.”

  • Cover Crops Helpful for Alabama Hemp Producers

    Cover crops are important tools and have various advantages for farmers transitioning from one season to the next. Eric Schavey, Alabama Regional Extension agent in Northeast Alabama, encourages hemp producers to plant their cover crops now before it’s too late in the season.

    Schavey

     “If you get into November, you’re a little late. Your cereal rye will do a little better than your clover. That clover likes temperatures between 65 degrees F and 75 degrees F. Your grains are a little more hardy to cold temperatures,” said Schavey, who encourages producers to plant in late September or October. “I’m a big a fan of a cover crop. It just holds in moisture. It’s going to add to your organic moisture. It slows down erosion. To me, a cover crop is there and with our hemp farmers especially, there’s not those weed control options that our row crop farmers have. That’s been some of the challenges that they have is controlling weeds in our in-row in hemp.”

    Cover crops planted in the row middles prevent sunlight from penetrating and allowing weed seeds to germinate.

    Schavey said such problematic weeds include pigweed and goose grass. He also has certain recommendations when talking about cover crop implementation.

    “I like using a cereal rye, not a rye grass but your cereal grains; also, your crimson clover is a good one. With those two, there’s the biomass that you get and their ease of growing there. They’ll grow in a lot of different soil types. That’s what I recommend,” Schavey said.

    According to a prior Alabama Extension news article, cover crops are crops grown to benefit the following crop as well as improve the soil. They can protect the soil, feed the soil eco-system, increase soil organic matter and supply nutrients to the following crops.

    The right cover crop can improve yields, soil and water conservation and quality and your bottom line.

  • Powdery Mildew Resistance Survey

    File photo shows muscadine vines in a vineyard.

    According to the UGA Extension Viticulture Blog, University of Georgia researchers are asking grape producers if powdery mildew has been spotted in their vineyards. UGA would love to sample it, and it could mean that the fungicide program is breaking down due to resistance development in the powdery mildew fungus.

    UGA graduate student Brooke Warres is working on QoI and DMI fungicide resistance in powdery mildew. She can take swab samples of the mildew from any part of the grapevine to test for mutations associated with resistance to these chemical classes. With this information, UGA can better understand resistance patterns in Georgia and determine how widespread these mutations are throughout the state.

    As producers are scouting their vineyard at the end of the season, UGA suggests looking inside the canopy to check for white to gray fungal growth of powdery mildew — predominantly on the upper leaf surfaces. Depending on how well it has been controlled, it may also be self-evident on the canopy exterior. If you are finding this disease, please call Brooke at 678-642-2183 or email at Brooke.Warres@uga.edu so she can visit to take a quick sample. With these samples, she will be able to let you know if you currently have QoI and/or DMI resistant populations in your vineyard. This should help you to plan your spray program for next season.

  • Shuck Decline in Pecans

    According to the UGA Extension Pecan Blog, shuck decline in pecans is starting to manifest itself in orchards across the state.

    Growers are starting to see symptoms of shuck decline in the orchard. Symptoms range from shucks turning all the way black to the tips, green shucks turning black and peeling back at the suture. In some cases, kernels are black and in other cases, there is no kernel. The degree of declining shucks varies from tree to tree.

    For growers to minimize the problem moving forward, they need to continue to irrigate. This will be critical if the weather turns dry later this month and in October.

    According to the UGA Extension Pecan Blog, the severity of shuck decline depends on when the decline started during development. If the shuck has already split open, likely, growers can still shake the nut from the tree and it will be fine. However, much of this dark color on the shucks beginning before they open may hurt yield and quality.

    Shuck decline is mainly a stress-related issue. It can be worse on trees with a heavy crop load.

  • New AI Technology ‘Agroview’ Named UF Invention of the Year

    Yiannis Ampatzidis with agricultural drones in the laboratory. Photo taken 09-23-19.

    September 23, 2020

    By: Brad Buck, 813-757-2224, bradbuck@ufl.edu

    Yiannis Ampatzidis and his research team combined their collective minds to find the artificial intelligence technology to best help farmers save money and better care for their crops.

    Out of that process, they invented a system known as Agroview.

    The system utilizes images from drones and satellites and from the ground – along with artificial intelligence — to assess plant stress, count and categorize plants based on their height and canopy area and estimate plant nutrient content. Agroview can reduce data collection and analysis time and cost by up to 90% compared to the manual data collection, Ampatzidis said.

    “Florida and U.S. growers can use this novel technology to count plants and predict yield, to detect stressed plant zones earlier and to develop maps for precision and variable-rate fertilizer applications,” said Ampatzidis, a UF/IFAS assistant professor of agricultural and biological engineering. “The maps can optimally apply fertilizers, reduce application cost and reduce environmental impact.”

    Agroview captured the eye of UF Innovate | Tech Licensing, which recently recognized the technology as a UF Invention of the Year.

    “I am extremely honored to receive this award,” said Ampatzidis, a young scientist who just entered his fourth year at UF/IFAS. “We truly believe that this AI-based technology could help Florida and U.S. producers improve crop productivity and management.” 

    He thanked his research team at the Southwest Florida Research and Education Center (SWFREC) in Immokalee for helping devise Agroview. He also expressed gratitude to his colleagues from the center and his academic department at the Gainesville campus for their input.

    “I would like to thank UF Innovate | Tech Licensing and especially Dr. John Byatt and Dr. Jackson Streeter for their great help to commercialize this invention,” Ampatzidis said.

    A spinoff company called “Agriculture Intelligence Inc.,” was created, which provides Agroview’s services to growers.

    His bosses are also impressed with the work of Ampatzidis and his team.

    “The Agroview product developed by Dr. Ampatzidis’ program provides the key for connecting UAV imagery to grower decisions. This product bridges a gap that existed between research and on-the-ground, everyday use,” said Kati Migliaccio, chair of the UF/IFAS agricultural and biological engineering department. “Dr. Ampatzidis uses AI in his programs to automate processes that have been traditionally been completed in more resource-expense ways. These efforts will allow for greater efficiency and optimization of the agricultural production process, which is necessary to meet future global food needs.”

    Ampatzidis’ center director, Kelly Morgan, said SWFREC has a long history of supporting vegetable and citrus production.

    “We have typically worked on standard inputs such as fertilizer, water and pesticides,” Morgan said. “Agroview is an example of the new emphasis on precision agriculture by the research center. This program will make growers in Florida much more efficient and result in far less environmental impact. This product of SWFREC should result in lower inputs of fertilizer, water and pesticides.”

  • FFVA’s Joyner: Government’s Self-Initiation of 201 Investigation Speaks Volumes About Importance

    The Florida Fruit and Vegetable Association (FFVA) is pleased with the USTR’s decision to implement a Section 201 investigation into blueberries. Mike Joyner, president of FFVA, said the investigation was best for blueberry producers, mainly because of its global approach.

    florida fruit
    Joyner

    “When you watched the testimony of the two hearings, there were a number of blueberry growers. We knew this already but when you look at blueberries and the impacts that they’re seeing, yes Mexico is having an impact on them, but other countries are probably having a bigger impact; Peru, Chile,” Joyner said. “It became very apparent that a Section 201 was probably going to be best for blueberries. The thing about Section 201 is it’s a global approach. It looks at all the countries.”

    Hearings

    Florida and Georgia blueberry producers were able to state their concerns about imports from other countries and the impact they have had domestic production, especially market prices, during two days of hearings in August. Joyner said the government’s decision to initiate a 201 investigation speaks to the magnitude of how it perceives the concerns brought forth by farmers.

    “When the government self-initiates, when they bring it to the International Trade Commission, it sends a signal that this is an important issue. The blueberry growers still have to put on the case. But just the fact that the U.S. Trade Reps Office said we’ve seen enough here that we’re going to self-initiate a 201, it just speaks volumes,” Joyner said. “I do think the 201 is the right trade tool for blueberries.”

    Section 201

    A Section 201 investigation is part of the Trade Act of 1974. It allows the International Trade Commission to investigate where domestic producers have been harmed by imports. They must be seriously injured, meaning that level of injury to their marketing opportunities. Typically, it must be completed within 120 days after filing.

    To read the plan, click here.

    Click here to read the full transcript of the virtual hearing held on August 13, 2020.

    Click here to read the full transcript of the virtual hearing held on August 20, 2020.

    To view all submitted comments to the public docket, click here.

  • UGA Vegetable Entomologist More Optimistic About Whiteflies Following Rain, Cooler Temperatures

    File photo shows how whiteflies can infest fall cucurbits.

    University of Georgia Cooperative Extension vegetable entomologist Stormy Sparks is more optimistic about the ongoing whitefly problem that farmers are facing this fall – especially more than what he was feeling two weeks ago. His reason for optimism? Remnants from a hurricane and a drop in temperatures.

    Remnants from Hurricane Sally and cooler weather this week should help knock back some of the whitefly populations, which were wreaking havoc on fall vegetable crops.

    The rain amounts were extreme in certain places last Thursday when the storm moved across the state. More importantly, the rain was widespread.

    “I would anticipate that the weather knocked down the adult populations and this cool weather will greatly delay or reduce the amount that they rebound. That’s what I would think would happen,” Sparks said. “The main thing was (the rain) was everywhere. We got some everywhere. That probably has much more impact than those local heavy rains that we normally get.”

    Weather Conditions

    According to the UGA Automated Weather Network, Cordele, Georgia received 5.3 inches on Thursday, Sept. 17, while Moultrie, Georgia received 2.36 inches.

    Temperatures also dropped from 81 degrees Fahrenheit on Sept. 16 to 67 degrees F on Monday, Sept. 21 in Moultrie.

    Whitefly Infestations

    Whiteflies have been a problem all year, dating back to early spring. An abnormally mild winter did not kill off many of the wild hosts that whiteflies overwinter on. The result was they became mobile earlier this past spring.

    Whiteflies cause feeding injury issues in vegetables and transmit two viruses: cucurbit leaf crumple virus and cucurbit yellow stunting disorder virus. Vegetables like squash, zucchini, cucumber, cantaloupe and snap beans are highly susceptible to these viruses. Commercial cultivars that have resistance or tolerance to these pathogens are not available.

  • UGA professor receives $5.4 million grant to combat destructive Asiatic fly

    UGA CAES photo/Ashfaq Sial is leading a multistate team of researchers to develop and implement long-term sustainable strategies to control spotted wing drosophila.

    By Emily Cabrera for CAES News

    The University of Georgia College of Agricultural and Environmental Sciences (CAES) has been awarded a $5.4 million grant by the U.S. Department of Agriculture’s National Institute of Food and Agriculture to develop long-term, sustainable methods for controlling the spotted wing drosophila (SWD).

    Native to Asia, SWD is a tiny fly that was first detected in California in 2008 and has since emerged as a devastating pest of small and stone fruits throughout the U.S., valued at $5.8 billion in damage annually. It affects soft-skinned fruits such as blueberries, blackberries, raspberries, strawberries, cherries and others.

    Blueberry entomologist and coordinator of the UGA Integrated Pest Management Program, Ashfaq Sial is leading a multistate team of researchers from 10 land-grant universities and the USDA to develop and implement long-term sustainable strategies to control SWD.

    The pest has caused blueberry crop losses of up to 20% annually. Blueberries are Georgia’s top fruit crop and ninth-largest agricultural commodity with an estimated $300 million in value, according to UGA agricultural economists.

    This project builds on previous work to develop control strategies in response to the crisis situation created after the detection and widespread distribution of this devastating invasive pest in all fruit-growing regions of the U.S. The team made substantial progress by refining monitoring tools, developing effective insecticide-based management programs, identifying effective cultural controls, and screening native and exotic biological control agents to address the drosophila invasion.  

    “The progress we’ve made is great, but SWD management is still highly insecticide dependent and is further challenged by secondary pest outbreaks, insecticide resistance and increased input costs,” explained Sial. “Because SWD has become established as a keystone pest throughout the U.S., it’s critical to develop more sustainable strategies to manage it.”

    The goal of this new project is to pivot away from crisis response to build a long-term, integrated and systems-based approach to managing SWD. The team will work with region- and crop-specific teams of growers to implement best management programs, evaluate alternatives to insecticides, assess and reduce the risk of insecticide resistance development, and develop and disseminate actionable recommendations that enable producers to optimize pest management decisions for sustainable SWD management. They will also develop economically based decision aid tools to increase profitability and evaluate the impact of these initiatives.

    The team aims to develop and deliver systems-based integrated management programs to berry and cherry growers that are cost effective and environmentally sustainable for long-term management of SWD in the U.S. Ultimately, implementing these solutions will directly contribute to the long-term profitability and sustainability of farms and farmers nationwide.

    Joining Sial on this project is Kay Kelsey, a professor and evaluation expert in the CAES Department of Agricultural Leadership, Education and Communication. Other collaborators and their institutions include Hannah Burrack, North Carolina State University; Kent Daane, University of California Berkeley; Rufus Isaacs, Michigan State University; Greg Loeb and Miguel Gomez, Cornell University; Cesar Rodriguez-Saona, Rutgers University; Philip Fanning, University of Maine; Elizabeth Beers, Tobin Northfield, Karina Gallardo and Gwen Hoheisel, Washington State University; Vaughn Walton, Oregon State University; Joanna Chiu and Frank Zalom, University of California Davis; and Kim Hoelmer and Xingeng Wang, USDA Agricultural Research Service in Newark, Delaware.

    To learn more on pest management strategies and research, visit site.extension.uga.edu/ipm.