AgNet DEMO

Category: Pests

  • Effectively Managing Pests While Protecting Pollinators

    By Sylvia Willis, Amy Vu and Jamie Ellis

    Pollinators play an important role in the production of crops around the nation. Different crops rely on different techniques for pollination. Corn, for example, uses wind to carry pollen to female flowers, whereas watermelon depends on pollinators to deliver pollen. Pollinators include insects, birds and bats.

    Many fruits and vegetables result directly from pollinators such as honey bees. In apple, cranberry, melon, broccoli and almond production, honey bees are the most common pollinator. Honey bees are responsible for a significant portion of the world’s food production and contribute nearly $20 billion to the crop industry by providing pollination services all over the United States.

    In Florida, the hot, humid climate is ideal for crop production throughout the year, but this favorable environment also paves the way for various pests that negatively impact crops year-round. Growers use integrated pest management (IPM) to consider the risks and benefits associated with cultural, chemical, biological or physical control methods to combat pests. Typically, as a last resort, a chemical control is utilized to save a crop. When selecting a pesticide, growers should consider a chemical’s efficiency of pest control and potential impacts on pollinators when applied. 

    PESTICIDE EFFECTS
    Bee hives. UF/IFAS Photo by Tyler Jones.

    There are many factors that contribute to honey bee and pollinator stress, one being the use of insecticides. Effects of certain pesticides on bees can vary from no harm to acute harm (bee or single colony death) to chronic harm (altered bee behavior or physiology, reduced reproduction, colony decline or death). Suspected pesticide exposure is one of many biological and environmental factors associated with bee colony loss. Bees are likely exposed to pesticides outside the hive when foraging during the day. Plant foliage, pollen, nectar and soil can all contain potential toxins after direct application or drift from certain pesticides.

    Reading and properly interpreting pesticide labels and exposure warnings to honey bees and pollinators is vital. According to the Environmental Protection Agency, if a product is intended for foliar application to crops and contains a pesticide toxic to pollinators, the label must include appropriate cautions. Examples of bee and pollinator hazard warning statements are:

    • “This product is toxic to bees exposed to treatment and for more than five days following treatment.”
    • “Applications to all crops may be made at any time. Fenpyroximate is practically nontoxic to bees and wasps when used according to this label.”
    PROTECTION PRACTICES

    Protecting pollinators from pesticide exposure is on the forefront of many growers’ minds when considering pest control methods. For crops that require bees for pollination, it is in the best interest of the grower to protect bees. Without proper pollination, the grower’s crop production and yield are negatively impacted. There are a variety of best management practices that growers utilize every day to minimize impacts on honey bees and pollinators. These include:

    • Following the label – THE LABEL IS THE LAW
    • Obtaining a pesticide license to legally spray pesticides
    • Applying pesticides only when necessary
    • Employing IPM practices and using chemical control as a last resort
    • Spraying pesticides at night (label permitting) to maximize safety of honey bees and other pollinators
    • Utilizing target pesticide application such as injecting, rather than broad application
    • Selecting pesticides that require fewer applications, minimizing risk potential
    • Applying less toxic formulations and compounds
    • Developing a pest management plan that considers bee foraging during bloom
    • Understanding a crop’s pollination requirements to minimize exposure
    • Planting beneficial plants along field edges to provide additional resources for honey bees and other pollinators
    • Maintaining a good relationship with beekeepers and notifying them in advance of an application
    • Consulting with fellow producers, beekeepers and Extension professionals for recommendations
    EXTENSION’S ROLE

    Through services and educational efforts offered by Extension services, growers are provided appropriate tools to combat pest issues while also protecting pollinators, the environment and human health. Extension provides educational classes to enhance grower knowledge of pollinator protection on topics such as IPM (i.e. monitoring techniques, pest and plant knowledge, and pesticide selection) and best management practices regarding pest control.

    If pesticide application is necessary, Extension provides the training, testing and necessary certifications required to apply pesticides legally. In addition, Extension highlights up-to-date pollinator protection label changes during trainings and classes. Additional efforts of Extension agents and specialists include providing updates throughout the growing season to inform producers on potential pest issues, pesticide recommendations, and notifying producers of possible impacts on pollinators of certain products. 

    Understanding the importance of pollinators on the food system has brought increased awareness for pollinator protection programs and trainings. Growers can make a difference by making informed decisions to select and utilize chemicals with pollinator protection in mind. By building positive relationships between beekeepers and growers, an open dialog of communication can be established. As a result, growers can rely on Extension services when questions on chemical safety regarding honey bees and other pollinators arise.

    See Minimizing Honey Bee Exposure to Pesticides at edis.ifas.ufl.edu/pdffiles/IN/IN102700.pdf for more information on sustainable production practices and guidance on risk-reducing strategies to protect honey bee and pollinator populations.

    Sylvia Willis is the University of Florida (UF) Institute of Food and Agricultural Sciences Extension agriculture agent in Suwannee County. Amy Vu is an Extension coordinator and Jamie Ellis is the Gahan endowed professor, both at the UF Honey Bee Research and Extension Laboratory in Gainesville.

  • Ant Control: Alabama Extension Encourages Farmers to Protect Crop

    Alabama Extension photo/Shows fire ants on okra.

    Vegetable crops are vulnerable to ant pressure this time of year. Alabama Extension encourages vegetable producers to implement management tactics as they begin planting this year’s crops.

    According to Alabama Extension, fire ants can protect aphids and other honeydew producers on vegetables, which makes their effects worse on the plants. Fire ants can also interfere with natural enemies. Ultimately, though, fire ants can damage crops like okra, potatoes, sunflowers and hemp.

    Cultural Controls

    It is important to control fire ant mounds around or outside the production area to prevent them from moving into the garden. It is also essential to manage excessive plant residue on the soil. This will aid in the detection of foraging ants. It provides ants fewer places to stay out of sight and makes it easier to apply bait insecticides on open ground.

    Insecticide Options

    The best time to apply baits is from April 15 to Oct. 15. Mound treatments can be done any time of the year on warm, sunny days above 65 degrees Fahrenheit when fire ants are active. Apply products close or on the mound after checking for foraging ants.

    For more information on fire ant control, read Managing Fire Ants with Baits located on the Alabama Extension website. More information is available in Fire Ant Control: The Two-Step Method and Other Approaches on the eXtension Foundation website.

  • Protecting Your Investment: Trap Cropping a Unique Insect Management Strategy

    Trap cropping is an insect management strategy that saves farmers time and money and protects the ecosystem, specifically beneficial insects, from overuse of pesticides.

    UGA CAES/Leaf Footed bug on vine ripe tomatoes Photo by Sharon Dowdy

    For example, using sorghum in a field alongside tomatoes protects the tomato crop from leaf-footed bugs. It’s a unique tactic of sacrificing one crop for the safety and protection of the money-making crop, says Ayanava Majumdar, Extension Professor in Entomology and Plant Pathology at Auburn University.

    “Just like we make choices every day. For example, if you’re hungry, you make the choice to go to either Cracker Barrel or you want to go to McDonald’s. You know what you’re getting. Just like you make choices, insects make choices on the go,” said Majumdar during a recent webinar. “It’s a very clever way of manipulating their behavior. That’s essentially what you’re doing. We are using their weakness against them.”

    Just as some might struggle to resist certain foods, insects struggle to resist certain plants. It is important to plant a trap crop a couple of weeks before the main crop so it can provide a perimeter around an entire field.

    What Works in Alabama?

    Majumdar said the trap crops evaluated in Alabama include sorghum and sunflower for leaffooted bugs; sunflower, browntop millet and pearl millet for stink bugs; okra, bell peppers and ornamentals for aphids; New England Hubbard squash for squash insects.

    Trap cropping also provides alternate benefits that could appeal to some producers.

    “I have seen sorghum, because of the height, it actually protects the plants from wind. Wind reduction is a benefit,” he said. “Weed control; if you have a lot of weeds around, you put that sorghum in there, the sorghum takes over. It grows like crazy on a good year.

    “Then the beneficial insects. That ecosystem has less pesticides, a lot of beneficial insects are in there, including spiders that you never see in a typical field or garden. It’s incredible to see some of the side benefits from trap crops.”

  • Mighty Mites: UGA Extension Encourages Scouting for Strawberry pests

    UGA CAES photo shows two-spotted spider mite.

    It won’t be long before strawberries will be ready for harvest in South Georgia. University of Georgia Extension encourages producers to scout for spider mites, especially as strawberries begin to ripen and bloom across the state.

    The two-spotted spider mites are typically light yellow in appearance with a spot on either side of their abdomen. Their piercing-sucking mouthparts can cause damage while feeding on the plant cells. Scouting is important since feeding usually occurs on the underside of the leaf.

    If left undetected, infestations can cause the leaves to become brittle with a bronze tint.

    Early detection is important since this is the time that strawberries are most vulnerable. According to the UGA Extension Strawberry News blog, strawberries can tolerate higher numbers of spider mites as the season progresses. The threshold now for strawberries if five per leaflet. The threshold moves up to 20 further into the season.

    The blog states, “There are several miticides on the market that work well on two-spotted spider mites. It is important to understand that some miticides are only effective on certain life stages. Using a product that is effective on eggs and juveniles will do no good if only adults are present.”

    Complete coverage is critical since mites feed on the undersides of leaves. Rates of 50 and 100 gallons of water per acre are common for controlling mites.

    UGA Extension advises farmers who need assistance or recommendations to call their local county agent.

  • Insect Report: Pests Currently Light for Georgia Vegetable Producers

    It is planting season for Georgia vegetable producers. They can take solace in knowing that insect pressure appears to be light right now, minus some pepper weevils. This is according to University of Georgia Cooperative Extension vegetable entomologist Stormy Sparks.

    UGA CAES photo/The pepper weevil is one of the most serious pests of peppers.

    “There’s concerns about pepper weevil as we’re getting peppers in the ground. We’re running traps in various counties, got county agents running traps in the major pepper growing regions and we’re still catching significant numbers,” Sparks said. “It’s not anything like it is early in the year. They drop off this time of year, but they’re not going to zero. We know we’re overwintering pepper weevil.”

    Sparks believes insect pressure will increase as Georgia vegetable producers head into April, specifically with thrips.

    “As we get into April, all this pollen that we’re seeing right now is just food for thrips. That’s why we always tend to have thrips populations in April. That’ll be popping fairly soon, probably,” Sparks said.

    Insect infestations increase as temperatures continue to heat up. Growers also need to be mindful of squash bugs.

    “Temperatures control insects so much; reproduction and everything, overwintering. We’ll have squash bugs coming out of overwintering in the next few weeks or month also,” Sparks said. “The cool weather just keeps them slowed down. We do have some whiteflies out there, but I don’t think there’s anything of significance. Again, the temperature keeps them low.”

    The exception to that rule is the diamondback moth.

    “It can explode or disappear anytime of the year. I’ve had a few reports of some diamondback moth activity but nothing of alarming levels,” Sparks said.

  • Record-Setting Populations: Asian Bean Thrips Spiking in Some Florida Fields

    UF/IFAS photo

    It was a record-setting week on some South Florida farms with respect to Asian bean thrips (ABT) populations.

    According to UF/IFAS, across most farms in southeastern Hendry County, ABT populations averaged 0.2 ABT per bud and ranged from 0.3 to 1.5 per bloom (at full bloom). But in an isolated located, reports were as high as 10.0 ABT per bloom (at full bloom).

    This was the highest population levels reported at this stage in Hendry County. Damage appeared to occur to the blooms.

    Whereas in northeastern Hendry County, populations varied considerably. No ABT populations were reported in some plantings, while others reached as high as 5.0 ABT per bloom at early pod development.

    In the central part of Hendry County, populations stabilized after increasing over the previous few weeks, dropping to 0.3 to 0.6 ABT per bloom (at full bloom).

    Other Counties

    Scouted beans are older in northern Collier County, and populations of 1.8 ABT per bloom were reported.

    In eastern Palm Beach County, reports indicate populations have steadied at 0.1 to 0.5 ABT per bloom or per plant. Aggressive insecticide programs include 1 to 2 spray pre-bloom to keep populations from building early and more aggressive sprays at bloom and later appear to keep ABT at moderate levels. Similar populations are reported in western and north western Palm Beach County.

    Beans were close to harvest, and ABT was not reported in southern Glades County.

  • South Florida Thrips Update

    Figure 4. Adult chilli thrips have fringed wings. Photo by Lyle J. Buss, University of Florida

    Various thrips species are causing problems for South Florida vegetable producers. According to the South Florida Pest and Disease Hotline, strawberry farmers have dealt with chili thrips all season in the Manatee Ruskin area. They are also showing up in pepper.

    In the Miami-Dade County area, melon thrips are increasing in populations in various crops.

    Along the east coast, western flower thrips are being found in pepper. From Jupiter, Florida northward, it is mostly Florida flower thrips that are a problem, though they can be controlled with insecticides.

    Thrips are moving into some pepper fields around Immokalee, Florida with a few fields having counts of 10 or more thrips per bloom.

    Click here for thrips management options.  

  • Whitefly Infestations: Pest Numbers Increasing in South Florida

    UGA photo shows whiteflies.

    Whitefly infestations continue to increase in vegetable fields in Southwest Florida. According to the South Florida Pest and Disease Hotline, tomato fields have been greatly impacted.

    Adult whiteflies are swarming young cucurbit plants, especially those transplants that have just been planted in the ground and those direct seeded crops.

    Growers and scouts report that whitefly pressure is increasing in some older eggplant and tomatoes along the east coast. They are moving out of these crops and applying pressure in nearby fields.

    Reports from farmers in Homestead, Florida, indicate that whiteflies are high in tomatoes and other crops. Maybe just as significant is that Tomato Yellow Leaf Curl Virus incidence is moderate to high in the majority of tomato fields.

    Click here for management options.   

  • Record Levels: Asian Bean Thrips Major Problem for Some South Florida Producers

    South Florida farms had record levels of Asian bean thrips (ABT) populations last week. Others experienced a reduction in thrips counts, however.

    According to the University of Florida/IFAS, farms in southeastern Hendry County reported infestations as low as 0.2 ABT per bud and between 0.1 and 0.2 ABT per bloom (at full bloom) but were as high as 1.9 ABT per bud and 6.2 ABT per bloom (at full bloom). This is the highest reported population levels at this stage in Hendry County and may lead to yield loss.

    ABT populations at this location in the previous cycle of Dec. 18 were just 0.1 ABT per bloom at full bloom.

    In central Hendry County, populations increased, but there was a wide range of 0.2 to 0.8 ABT per bloom at full bloom, while in northern Collier County, ABT was reported at 0.2 ABT per bloom in plantings at full bloom, with most plantings already harvested.

    In eastern Palm Beach County, reports indicate background populations have steadied between 0.1 and 0.3 ABT per bloom amid aggressive insecticide programs.

    Click here for management recommendations.

  • Nematodes: Hidden Enemies of Asian Vegetable Growers in Florida

    By Mengyi Gu, Hung Xuan Bui and Johan Desaeger

    If you happen to travel around Wimauma, Florida, you will see many plastic tunnels and may wonder what they are. Asian farmers (mostly Vietnamese) are using those plastic tunnels to grow a wide variety of specialty Asian vegetable crops.

    Root-knot nematode galls on pumpkin roots

    There is a high demand for these vegetables from northern cities such as New York and Chicago, especially during the winter. In the United States, the demand for ethnic and specialty vegetables is rapidly increasing, and Asian vegetables have become one of the most popular specialty crops. The growing population of Asians, the blooming ethnic cuisine restaurants, and the demand from American consumers for Asian vegetables in their diet has boosted Asian vegetable production in Florida.

    The climate in Florida is very favorable year-round for growing many of the popular Asian vegetables. According to the 2019-20 Vegetable Production Handbook of Florida, currently more than 40 Asian vegetables are grown on 8,000 acres across Florida (with an increase of more than 3,400 acres over the past years). Some of the most common Asian vegetables grown in Florida include bok choy, long bean, bitter gourd, Thai basil, Malabar spinach, water spinach and mizuna.

    Recommendations for weed, insect and disease management in Asian vegetables have been published in the handbook. However, nematode management recommendations for these specialty vegetables are not available, and few growers are even aware of the existence of nematodes in their fields. Also, most of these ethnic farms are typically small (less than 50 acres), and many of them do not have pesticide licenses due to the language barrier. Because of this, these farmers tend to be isolated and have limited access to pest and disease management information.

    WHAT WAS FOUND

    During the past year, postdoctoral associates from the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) Gulf Coast Research and Education Center (GCREC) nematology laboratory led an effort to visit some of the ethnic vegetable farms in Wimauma. The objective was to learn more about the crops that are grown and if nematodes are a problem. Most farmers were unaware of a nematode problem, but results indicated that five of the six surveyed farms did have visible nematode damage in the form of stunted and chlorotic plants. A total of 16 different vegetables were sampled, mostly leafy, but also some fruiting and root vegetables (Table 1).

    Table 1. Plant-parasitic nematodes found on different ethnic Asian vegetables grown in Florida

    Root-knot nematodes were the most commonly found and appeared to cause the most damage. Other potentially damaging nematodes that were found were sting, stubby root and lesion nematodes. While it is not known how much damage nematodes cause on these farms, Thai basil, pumpkin, Malabar spinach, Indian taro, sweet potato, jute, bitter gourd, luffa and Chinese eggplant showed visible aboveground symptoms, such as leaf yellowing and wilting.

    Plant-parasitic nematodes are microscopic roundworms that feed on living plant tissues. Most nematode species feed on the belowground parts of plants like roots and tubers, although some species feed on aboveground plant parts, which can sometimes be seen on strawberries in Florida. There are no typical aboveground symptoms of nematodes feeding on roots, and often their damage may be misidentified with other causes such as nutrient or water deficiency, or diseases related to bacteria or fungi (stunting, wilting and yellowing).

    It is estimated that global agriculture production loses more than $100 billion annually due to nematode damage. In Florida, year-round warm weather and high humidity create a perfect habitat for many plant-parasitic nematodes, and nematode damage can be very severe, especially in sandy soils.

    NON-CHEMICAL CONTROLS

    Since most Asian vegetable crops do not have a pesticide label, growers must rely mostly on non-chemical nematode management methods. Sanitation should always be the first recourse against nematodes.

    Growers should select sites with no or low nematode populations and avoid the introduction of nematodes into the field. It may be tedious, but it is important to clean farm equipment before and after working in different fields.

    A common way that nematodes are introduced into fields is through infected plant material (transplants or tubers). While it is generally difficult to recognize whether plant material is infected with nematodes, in the case of root-knot nematodes, the presence of galls or knots on roots of transplants or tubers is a telltale sign. However, nematode galls can easily be overlooked when they are small or when roots are covered with soil. For most other nematodes, no real diagnostic root symptoms can be observed on planting material, and proper diagnosis will need to be done at a nematology lab.

    Frequent applications of organic amendments (animal and green manures, compost, etc.) will increase soil organic matter and microbial activity while stimulating natural enemies that may reduce the damage caused by plant-parasitic nematodes.

    Crop rotation with nematode poor-host plants could be another option for Asian vegetable growers, but not enough is known now on nematode host status of Asian vegetables to make good recommendations. Planting cover crops in between vegetable crops is a widely adopted nematode-management strategy. For managing root-knot nematodes, sunn hemp and sorghum-sudangrass are recommended as cover crops since they are known to be poor hosts.

    The GCREC laboratory can help growers identify if they have nematode problems in their fields. Soil and root samples can be submitted to the laboratory free of charge. For more information, contact hungbui@ufl.edu (English or Vietnamese) or gumengyi@ufl.edu (English or Chinese).

    Mengyi Gu is a postdoctoral associate, Hung Xuan Bui is a postdoctoral research associate, and Johan Desaeger is an assistant professor — all at the UF/IFAS GCREC in Wimauma.