by Danielle S. Williams | Nov 4, 2020
Danielle Sprague is the Agriculture and Natural Resources Extension Agent in Jefferson County, Florida and has been for almost three years. Danielle is originally from the land of Indian River Grapefruit, otherwise known as Vero Beach, Florida! Her Extension program areas include Agriculture, Horticulture and Natural Resources.
As a young girl, Danielle always thought she would be a nurse. She always wanted to help others and make a difference in her community. It wasn’t until she was exposed to the agriculture industry through 4-H in high school, did she realize there were other avenues to do so. With a newfound appreciation and passion for the agriculture industry, Danielle changed career paths completely.
She went on to earn her Bachelor’s degree in Agriculture Studies from Warner University in Lake Wales, Florida. While at Warner University, she completed internships at the UF/IFAS Citrus Research and Education Center as well as with Dow AgroSciences. Following that, she earned her Master’s degree in Entomology from the University of Florida where she worked as a Graduate Research Assistant at the UF/IFAS North Florida Research and Education Center in Quincy. She considers her current position as an Agriculture Extension Agent her dream job.
Danielle teaching about insects.
When she isn’t working, Danielle enjoys boating, fishing, hunting, camping, visiting different agritourism operations, pretty much anything outdoors! She also enjoys cooking and baking.
by Danielle S. Williams | Sep 14, 2020
Whitefly adults and eggs. Photo Credit: James Castner, University of Florida, IFAS.
Whiteflies are a pest we typically see in the fall but if you look around, you’ll notice high densities of them now. Despite their name, whiteflies are more closely related to an aphid or scale insect than a fly. They are 1/16 of an inch long (about the size of a gnat) and resemble small moths. They can be found on the undersides of host plant leaves and their behavior is easily recognizable as they scatter from the leaves when they are disturbed.
Silverleaf Whitefly. Photo by Lyle Buss, UF/IFAS
You’ll find whiteflies on a variety of plants ranging from ornamentals such as ficus, poinsettia, hibiscus, and ivy to vegetables like tomato, pepper, eggplant and okra. Some species feed on sweet potatoes, vegetables in the cabbage family, and citrus.
There are several species of whiteflies in Florida but the three main species of agricultural and horticultural concern are the silverleaf whitefly (also known as the sweet potato whitefly), citrus whitefly, and the ficus whitefly. Whiteflies have piercing-sucking mouthparts with which they feed on plants. The top side of leaves on infested plants may become pale or spotted due to whiteflies feeding on the undersides of leaves. It’s not uncommon for an infestation of whiteflies to go unnoticed until leaves turn yellow or drop unexpectedly. Some whitefly species can cause greater damage by transmitting plant viruses.
Whiteflies, along with aphids, scales and mealybugs excrete a sugary substance known as honeydew. This honeydew coats the surface of the plant where the insect feeds and facilitates the growth of a black fungus called sooty mold. Ants and wasps also feed on the honeydew secreted by these insects and may serve as an indicator that a plant is infested with whiteflies or other honeydew secreting insects.
Adult female whiteflies can lay anywhere from 200-400 eggs in her lifetime. The eggs are laid on the undersides of leaves. These eggs hatch into nymphs (also known as crawlers) after 4-12 days. From there, the crawlers will insert their mouthparts into the leaves of host plants where they will molt, pupate and then become adult whiteflies. This process takes anywhere from four weeks to six months, depending on temperature and humidity.
Whiteflies are difficult to control due to their prolific reproductive cycle. It is difficult to get rid of whiteflies once there is an infestation. As with dealing with most insects, proper plant selection, irrigation, and fertilization are critical for managing whiteflies. Removing sources of infestation such as weeds around the garden or old plant debris around the yard can help prevent whitefly populations from carrying over to the next season. Natural predators such as lady beetles, lacewings and predatory mites can help keep whitefly populations in check.
Insecticides such as insecticidal soap or horticultural oil can be used to help reduce whitefly populations. Be sure to always read the label for instructions. For more information on whiteflies, please contact your local UF/IFAS Extension Office.
by Danielle S. Williams | May 7, 2020
‘Early Pride’ Tangerine. Photo courtesy of Danielle Sprague.
Citrus is not only a vital part of our economy in Florida but it’s also a major component in our landscapes. Having grown up in the major grapefruit producing region of Florida, the citrus industry is near to my heart. So for me, it is very exciting to see all of the interest in the citrus industry in North Florida despite the devastation the industry is facing in South Florida. With many folks spending more time outdoors and working in the landscape, I wanted to share some ways homeowners can enjoy citrus in their landscape all while protecting the future of the citrus industry in North Florida!
First thing’s first…identification!
It’s important to be aware of some of the major pests and diseases affecting citrus. Fortunately for us in the Panhandle, many of the major pests and diseases troubling citrus to the south haven’t become quite as widespread in our area, and with your help we can keep it that way! Regularly scouting the citrus in your landscape and detecting any major pests or diseases early will be very important to prevent it from spreading.
The first major disease all Floridians should be aware of is citrus greening. Citrus greening or huanglongbing (HLB) is the major disease affecting the citrus industry worldwide. It is a bacterial disease caused by the bacteria Candidatus Liberibacter. The bacterium is spread from tree to tree by a tiny insect known as the Asian citrus psyllid. Psyllids spread the disease by feeding on infected trees and moving on to non-infected trees. Once the tree is infected, there’s little hope for survival as there is no cure for citrus greening.
Citrus greening can be difficult to diagnose as it can be easily confused with nutrient deficiency. Symptoms of citrus greening include yellowing of the veins and a blotchy mottle pattern. Nutrient deficiencies tend to have a symmetrical pattern on each side of the leaf vein whereas citrus greening is asymmetrical. Overall, a tree infected with citrus greening will appear unhealthy with discolored leaves, a thin canopy, and reduced fruit production.
Citrus Canker presenting on a leaf. Photo courtesy of Danielle Sprague.
Another disease to be on the lookout for is citrus canker. Citrus is also caused by a bacterial pathogen but is spread primarily though wind, rain and human movement. Citrus canker is highly contagious and can spread very rapidly. Transporting infected plant material from an area where canker is present is the primary means of spreading the pathogen.
Purchase from a certified nursery!
One of the absolute most important things you can do if you are planting citrus is to purchase your trees from a certified citrus nursery! A certified nursery has been inspected by the state to confirm that the nursery is producing clean, disease free trees. Citrus trees grown in a certified nursery will have a tag with the name of the nursery, registration number, the tree variety, and rootstock.
When buying a tree from a secondary retailer, you will want to be sure to examine the tree for any signs and symptoms of pests and diseases. A healthy tree will have dark green leaves, a smooth trunk and show no signs of wilt.
Certified nursery label. Photo courtesy of Danielle Sprague.
Other ways to protect citrus:
- Learn how to properly care for citrus trees. Proper watering an fertilization will make them less susceptible to pest and disease.
- Report any suspected pest and diseases to the Florida Department of Agriculture and Consumer Services (FDACS) Division of Plant Industry by calling 1-888-397-1517
- Don’t bring back plants or fruit into Florida! They could introduce new pests and diseases.
Keeping the Panhandle free of citrus greening and citrus canker will play a major role in the success of the citrus industry in North Florida. For assistance with pest and disease identification or for more information, contact your local Extension agent.
by Danielle S. Williams | Apr 1, 2020
Fertilizer Spreader – Image Credit Les Harrison ,UF / IFAS Extension
Plants require nutrients to grow and they typically get them from the soil. Oftentimes, we apply fertilizer to help them along. Fertilizers provide specific nutrients for your plants and are available in a variety of different forms. When used correctly, fertilizers are a great tool that can help plants thrive. If used incorrectly, fertilizers can harm plants and also the environment.
Different plants have different nutrient requirements and in many cases, fertilizer may not be necessary so do your research before purchasing fertilizers. Sometimes, certain plants, like azaleas or blueberries, need a special formulation of fertilizer.
Think about having your soil tested to see what nutrients are already present in your soil. Contact your local Extension Office for sampling procedures.
Fertilizer Components
Most fertilizers used in the home landscape and garden are blends of several elements mixed together to create a specific formulation of plant nutrients.
Macronutrients
Macronutrients are nutrients required by plants in relatively large amounts for optimum growth. The three main nutrients contained in fertilizers are nitrogen (N), phosphorus (P), and potassium (K). Most folks are familiar with these because they are represented by three numbers that appear on the fertilizer bag. You may be familiar with the term ‘complete fertilizer’. This means the fertilizer with contain all three of the major plant nutrients – N, P and K. Other macronutrients include calcium (Ca), magnesium (Mg), and sulfur (S).
Micronutrients
Micronutrients are nutrients most plants need in small quantities. They are sometimes referred to as trace elements or minor elements. These nutrients include boron (B), chlorine (Cl), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), and zinc (Zn). They are often available in sufficient quantities in the soil, but are also present in many fertilizers. Micronutrients are also sold as individual nutrients.
Types of Fertilizer
Inorganic Fertilizers
Inorganic fertilizers are materials that are mined or synthesized from non-living materials. Many inorganic fertilizers contain nutrients that are immediately available to plants. Others are formulated to be released over a period of time.
Organic Fertilizers
Organic fertilizers are materials that are derived from plants and animals. One of the most common forms of organic fertilizers is manure. Organic matter incorporated into the soil before planting will help fertilize your vegetable plants, but you’ll need to add additional fertilizer after planting.
The quick availability of nutrients, especially nitrogen, is very important in vegetable growing. Therefore, you may want to supplement any organic fertilizer you apply with some inorganic fertilizer for quick feeding. It is a common practice for gardeners to use a combination of fertilizers and techniques in the garden.
Slow- or Controlled-Release Fertilizers
Slow- and Controlled-Release fertilizers provide nutrients to plant roots over an extended period of time. This allows you to fertilize less frequently and prevent nutrients from leaving your landscape and entering groundwater or waterways.
Understanding a Fertilizer Label
The fertilizer label includes a series of numbers that indicate the percentage of nitrogen, phosphorous, and potassium, by weight. The numbers will read something like 15-0-15 or 16-2-8. The first number represents the percentage of nitrogen in the bag, the second refers to phosphorus, and the third number is the amount of potassium. For example, a 50-pound bag of 16-2-8 is 16% nitrogen (8 pounds total); 2% phosphorus (1 pound total); and 8% potassium (4 pounds total). The remaining weight is usually comprised of inert ingredients.
Preventing Pollution
- Follow UF/IFAS Recommendations. Rates, application timings and formulas vary depending on the plant.
- Do not fertilize before a heavy rain. If rain is in the forecast for the next 24 hours, wait to apply fertilizer. Heavy rains can cause fertilizer to leach into groundwater.
- Keep fertilizer off hard surfaces. If fertilizer is spilled on a driveway or sidewalk, sweep it up and dispose of it. Fertilizers can wash into storm drains and nearby bodies of water.
For more information on fertilizers visit:
The Fertilizer Label
by Danielle S. Williams | Jan 23, 2020
Resurrection Fern on Pecan Tree. Image Credit Danielle Sprague, UF/ IFAS Extension
This week, I received a call about identifying a plant growing on a pecan tree in someone’s yard. With the recent rain we’ve experienced after a rather dry period, I had a pretty good feeling it was a resurrection fern. A quick picture sent in to me by the homeowner confirmed this.
Resurrection fern, Pleopeltis polypodioides is a native fern found in many hardwood trees throughout the southeast. In our area, it is found most often on the branches and trunks of live oak and pecan trees. The resurrection fern gets its name from its ability to withstand extensive periods of drought by shriveling up and appearing dead. When it is exposed to water again, it will ‘come back to life’, uncurling its fronds and appearing bright green.
This creeping fern has a long, skinny stem to which the fronds or leaves are attached. The stem is less than 1/12″ in diameter and fronds are anywhere from 4 to 12 inches long. Unlike other plants, resurrection fern reproduces by spores, not seeds. These spores can be found on the underside of the fronds in clusters known as sori. The sori look like brown to black scales.
Resurrection Fern before and after, Image courtesy IFAS Gardening Solutions
Resurrection fern is a perennial epiphyte or ‘air plant’, meaning that it attaches itself to other plants, but it does not steal water or nutrients from its host plant. Instead, it absorbs water and nutrients that collect on the outer surface of the bark. One of the questions posed by the homeowner was the need to control the resurrection fern, however, since it is an air plant and does not harm the tree, there are no chemicals recommended to control it.
In 1997, the resurrection fern made its first debut in outer space! Because of its unique attributes, the National Aeronautics and Space Administration (NASA) launched into space for an experiment to study the ‘resurrection’ in zero gravity. Amazingly enough, they found that the resurrection fern was able to rehydrate and recover in zero gravity!
For more information on resurrection ferns:
UF/IFAS Gardening Solutions: Resurrection Ferns
Island Ecology: Resurrection Ferns
Danielle Sprague is the Agriculture and Natural Resources Extension Agent in Jefferson County, Florida and has been for almost three years. Danielle is originally from the land of Indian River Grapefruit, otherwise known as Vero Beach, Florida! Her Extension program areas include Agriculture, Horticulture and Natural Resources.
