Throughout the year I get calls asking about this mossy-like stuff growing on the bark of trees. For the most part, the calls are in the spring time when people have come out of winter hibernation and see their landscape plants covered with this alien figure. I am here to say that it is not an alien figure, though it may look like it is. These are lichens.

Photo Credit: Eddie Powell

Lichens often get mistaken for some unusual fungus that is killing trees. However, lichens are not single organisms, but rather a combination of two organisms that live together in a mutually beneficial way. There are over 20,000 different types of lichens found in nature. Lichens consist of a fungus and an algae; the fungus is more dependent upon its algae partner which produces enough food for both to survive. Lichens are very different from plants in that they can survive a complete body water loss. During this time, brittle pieces that flake off can later grow into new lichens. When moisture becomes available again, the lichen absorbs water and returns to its fleshy form.

The lichens growing on trees and shrubs are not parasites and do not harm the plants in any way. The lichens use the landscapes as a structure to become established.

There are four different forms of lichens found, crustose (crust-like, growing tight against the substrate), squamulose (tightly clustered and slightly flattened pebble-like units), foliose (leaf like, with flat sheets of tissue not tightly bound), and fruticose (free-standing branching tubes). Colors range from white to gray, green, red, yellow, and black. Lichens commonly found in our area are in the crustose, foliose, or fruticose form, and are white, gray, or gray-green in color.

Because lichens produce chemicals, they have very few natural predators. However, the most serious threat to lichens is air pollution. Most lichens will not grow in a polluted atmosphere and therefore you should be glad to see lichen here or there in your yard, as this is an indication that the air is relatively clean.


Protecting Vegetables from the Heat

Protecting Vegetables from the Heat

Shade House for early fall crop Credits: UF/IFAS

Shade House for early fall crop
Credits: UF/IFAS

In fall, many Florida homeowners enjoy growing their own vegetables but are faced with late summer heat issues. This happens during the first few days of August here in north Florida. Most cole crops are recommended to be planted for the fall as early as August 1, but they must be protected from the hot weather or they may need to be replaced if hot weather damages them. A diverse selection of both heat-resistant and tender plants should be planted in order to prevent total devastation of the garden by extremely hot weather.

The site selection for tender plants should be number one on your list when protecting from heat. Fall vegetable plants need a site with good air flow to protect them from the early season hot temperatures. Arranging susceptible  plants along a shade barrier can protect them from direct hot sun, especially from afternoon sun. Poorly drained soils result in weak shallow roots which are more susceptible to drying out during a heat wave.

Plants grown with the correctly applied rate of nutrients will tolerate hotter temperatures better and recover from wilt injury faster than plants grown with little to no nutrients. Watering vegetable garden plants early in the day can help protect them. A well-watered soil will stay cooler than a dry soil and keep plants hydrated. However, saturated soil conditions can damage the root systems of most plants over a few days, so make sure the ground is well-drained.

Healthy vegetable plants are more resistant to heat than vegetable plants weakened by disease, insect damage, or nematode damage. Routine inspection for pests and implementation of necessary control measures are essential. Feel free to contact your local county extension office for information on pest identification and recommended controls.
Shade cloth coverings can help protect vegetable plants more from extreme hot temperatures during the beginning of fall gardening. Shade Cloth that extend to the ground and are not in contact with the vegetable plants foliage can lessen heat injury to the plant. If the vegetable plant foliage is in contact with the cover it is often dried out or injured because of heat transfer from cover the foliage can burn the leaves. One example of excellent plant covers is shade cloth or even an old trampoline cover. To learn more on heat protection of vegetable plants call your local UF/IFAS Extension Service


Tomato Spotted Wilt Virus

tomato spotted wilt on leaves Photo Credits: IFAS

Tomato spotted wilt on leaves
Photo Credits: IFAS

Tomato Spotted Wilt on Fruit Photo Credit: IFAS

Tomato Spotted Wilt on Fruit
Photo Credit: IFAS

The spotted wilt virus has a wide host range and can affect tomatoes, peppers, plus many other vegetables and ornamental plants. Early symptoms of spotted wilt on tomato are difficult to diagnose. Young, infected plants may show an inward cupping of leaves, and the foliage may appear light color or have a slight bronze cast. As the disease progresses, plants may develop dark brown to black streaks on the main stem. Occasionally the top portion of the plant appears yellow or wilts.
The most characteristic symptom of spotted wilt appears on the fruit. On young fruit white to yellow concentric rings will develop on the fruit skin. The area within the ring typically is raised, which gives the fruit a bumpy appearance. The bright yellow rings on mature red fruit are easily diagnosed as spotted wilt.
The spotted wilt virus is transmitted from plant to plant by several species of a small insect called a thrips. Thrips are less than ¼ inch in length, light green to brown in color and are extremely difficult to find on the plants. It is very important to keep the weeds around the garden controlled because many weedy plants serve as alternate hosts for the virus vectors.
Virus diseases cannot be controlled once the plant is infected. So plant resistant varieties*! Sanitation will help with controlling virus diseases. Infected plants should be removed immediately to prevent spread of the pathogens. Perennial weeds, which may serve as alternate hosts, should be controlled in and adjacent to the garden. Avoid planting tomatoes next to peppers, or other vegetables and flowers susceptible to these diseases. Preventative control of insects, especially thrips, will help reduce the likelihood of spotted wilt.

*BHN 602, Amelia, Crista, Quincy, Bella Rosa, Top Gun, Fletcher, Mountain
Vegetable Garden Disease and Pest Controls

Vegetable Garden Disease and Pest Controls

During this growing season monitor your plants and keep them healthy as a healthy plant will be able to better survive an invader attack.

Nematode populations can be reduced temporarily by soil solarization. It is a technique that uses the sun’s heat to kill the soil-borne pests. Adding organic matter to the soil will help reduce nematode populations as well. Nematodes are microscopic worms that attack vegetable roots and reduce growth and yield. The organic matter will also improve water holding capacity and increase nutrient content.

Tomato Spotted Wilt Virus
Credits: UF/IFAS

If you choose to use pesticides, please follow pesticide label directions carefully. Learn to properly identify garden pests and use chemicals only when a serious pest problem exists. If you have questions please call your UF/IFAS county extension office. We can provide helpful information about insect identification.

Organic gardeners can use certain products like BT(Dipel) to control pests. Please remember not every off-the-shelf pesticide can be used on every crop. So be sure the vegetable you want to treat is on the label before purchasing the product.

Follow label directions for measuring, mixing and pay attention to any pre-harvest interval warning. That is the time that must elapse between application of the pesticide and harvest. For example, broccoli sprayed with carbaryl (Sevin) should not be harvested for two weeks.

Spray the plant thoroughly, covering both the upper and lower leaf surfaces. Do not apply pesticides on windy days. Follow all safety precautions on the label, keep others and pets out of the area until sprays have dried. Apply insecticides late in the afternoon or in the early evening when bees and other pollinators are less active. Products like malathion, carbaryl and pyrethroids are especially harmful to bees.

To reduce spray burn, make sure the plants are not under moisture stress. Water if necessary and let leaves dry before spraying. Avoid using soaps and oils when the weather is very hot, because this can cause leaf burn.

Control slugs with products containing iron phosphate.

Cucumber Mosaic Virus
Credits: UF/IFAS

Many common diseases can be controlled with sprays like chlorothalonil, maneb, or mancozeb fungicide. Powdery mildews can be controlled with triadimefon, myclobutanil, sulfur, or horticultural oils. Rust can be controlled with sulfur, propiconazole, ortebuconazole. Sprays are generally more effective than dusts.


Consider Growing Vegetables in a Container

Five Gallon Container Plants
Credit: Eddie Powell

One Gallon Container Plants
Credit: Eddie

GARDENING IN A BUCKET: Grow wholesome, healthy vegetables in a container with this plan.

  • 5 Gallon plastic buckets
  • 40 pound sacks of Potting soil
  • 40 pound sacks of compost
  • garden trowels or shovels
  • wheel barrow or other large mixing container
  • controlled release fertilizer
  • packs of vegetable seeds


Recommended: All Herbs, Tomato, Cucumber, Squash, and Zucchini
  • In a large container or on a plastic mat on the ground, mix potting soil and compost in a 2:1 ratio. Two scoops of soil and one of compost, add ½ cup time release fertilizer, every 6 weeks
  • Drill 6 to 8- ½ inch holes in the bottom of the 5-gallon buckets. Make sure that the buckets did not contain toxic materials!
  • Fill the bucket to within 3 inches of the top of the container
  • Place container in sunny spot that will allow drainage
  • Plant chosen vegetable with two seeds in center of the container
  • Water well and keep moist but not wet


Plant requirements:
  • Minerals. Basic needs in plants are Nitrogen (N), Phosphorus (P), Potassium (K). These are listed on all fertilizers as a ratio, example – 8-8-8 contains 8 % Nitrogen, 8% Phosphorus, and 8% Potassium 76% being filler.
  • Sunshine or artificial sources of light (grow lights).
  • Water. Soil must be kept moist but not wet. Wet soils will create root-rot and encourage fungus. Measure moisture by pinching the soil to determine if the soil is moist. Adding water as needed; plants in full sun will need much more water than plants in partial shade. Wilted plants need more water!
  • Carbon Dioxide (CO2). Plants absorb CO2 and give off Oxygen making them VERY important to human and all animal life.
  • Proper Temperatures. Too cold, plants die, too hot plants die. Make sure that if your plants are outside and the temperature goes below freezing, the plants are protected.