by Blake Thaxton | Oct 21, 2014
Cross-Striped Cabbageworm – Photo credits: Blake Thaxton
Panhandle gardeners have their fall gardens planted and our growing rapidly. What the gardeners may start noticing is shotgun damage to cabbage leaves in their garden. The suspect for this damage is the Cross-Striped Cabbageworm.
The Cross-Striped Cabbageworm have black and white markings on the back of the caterpillar and a bright yellow stripe on each side. This particular caterpillar feeds in cluster and maybe limited to a hot spot of a few plants in the garden or production area. They feed on tender parts of the cabbage including the terminal bud and can feed into the head once heading is initiated.
Damage caused by Cross-Striped Cabbageworm – Photo Credit: Blake Thaxton
With all pest control the three levels of control should be used:
- Level 1: Systems-based practices – weed control of pest host weeds
- Level 2: Mechanical and physical practices – A barrier, such as a light cloth that still allows enough light, can be used when the plants our young to prevent the moths from laying eggs on the cabbage.
- Level 3: Soft chemical & other materials – Bt (Bacillus thuringiensis) products can be used on the small-sized caterpillars. Harsher chemicals can kill the adults but in a garden situation picking them off and disposing them in a bucket of soapy water will do the trick as well.
by Beth Bolles | Oct 14, 2014
Hover Fly. Image Credit EDIS, Roy Frye
When someone mentions flies, we think of buzzing around our heads, maggots in decomposing materials, and unclean conditions. It is time to change those thoughts, at least in the garden. There are several flies commonly found in landscapes that provide a valuable service in pest management. The long-legged fly is a beautiful fly that is normally metallic copper, blue or green. It is very slender with long, thin legs and is common in most gardens. The larvae or maggots can be found in moist soil or rotted vegetation and like the adults are predaceous on aphids, thrips, mites, and other small-bodied arthropods. The hover fly is also found around flowers and has the rare ability to hover and fly backwards. Because of their yellow-striped abdomen and similar coloring, these flies are often mistaken for bees. Adults visit flowers for nectar and help with pollination while the larvae primarily feed on aphids.
The tachinid fly, is similar to the house fly in appearance, but is an excellent parasite of pest caterpillars, beetles and bugs. The adults are gray or black in color with stiff hairs on their bodies. The larvae spend their lives feeding inside the bodies of unwanted insects and are so valuable that exotic tachinids have been introduced into North America as part of biological control programs.
Tachinid Fly. Image Credit UF / IFAS Entomology Department
by Matthew Orwat | Sep 30, 2014
Saddleback Caterpillar, Acharia stimulea. Image Credit Matthew Orwat
In Florida, there are a dizzying array of caterpillars that turn into beautiful or interesting moths or butterflies. Most are harmless except to the plants they munch on. There are a few that will cause humans pain if they are handled or touched. One of these venomous caterpillars is called the Saddleback, which is native throughout the eastern United States and is found throughout Florida home gardens. Many caterpillars only feed on specific and limited species of plants. The Saddleback caterpillar, Acharia stimulea, can be found anywhere in the home garden because it eats a wide variety of plants.
This caterpillar is quite a bit shorter than other Lepidoptera and has brown ends covered with venomous spines. The central portion of the body is bright green with a brown dot in the center. The spines on the front and back of the caterpillar are hollow and can break off and embed in the skin when disturbed. They contain hemolytic and vesicating venom, which cause burning sensations on and reddening of the skin; later sweating and blistering. Spines should be removed promptly before any other treatment methods are applied.
The best strategy for managing this insect is prevention of sting. If working in the yard in dense growth where these might not be easily observed, wear gloves and long sleeves. They are not aggressive and very slow moving, so they are easily avoided. Since they are seldom present in large numbers, the preferred method of control is removal from plants with forceps. Registered insecticides, such as those containing Bt (Bacillus thuringiensis), are effective controls of this insect.
Saddleback Caterpillar, Acharia stimulea. Image Credit Matthew Orwat
- Aster spp.; Helianthus spp., sunflower and artichoke
- Cycas revoluta, cycad, sago ‘palm’
- Vaccinium spp., blueberry, cranberry, huckleberry
- Castanea spp., chestnut; Quercus spp., oak
- Carya illinoinensis, pecan
- Lagerstroemia indica, crape myrtle
- Hibiscus rosa-sinensis, Chinese hibiscus; H. syriacus, rose of Sharon; Malvaviscus spp., wax mallow; Tilia spp., basswood
- Eriobotrya japonica, loquat; Malus pumila, common apple; M. sylvestris, crabapple; Photinia spp.; Prunus serotina, black cherry; Pyrus spp., pear; Rosa spp., rose
- Coffea arabica, mountain coffee; Gardenia spp.; Ixora coccinea, jungle geranium
- Citrus aurantium, bitter orange; C. limonia, rangpur; C. paradisi, grapefruit; C. sinensis, sweet orange; Fortunella spp., kumquat
For more information, please consult with publication # EENY 552 “Saddleback Caterpillar Acharia stimulea” or your local extension office.
by Taylor Vandiver | Sep 9, 2014
What’s eating my lawn? Does your grass look ragged in areas, as if someone randomly used a weed-eater here and there? Are you noticing brown patches that have a closely clipped appearance compared to other areas of your lawn? Your turf may be playing host to Tropical Sod Webworm.
Sod webworm damage in a home lawn. Photo courtesy UF/IFAS.
Sod webworm damage is subtle at first. You have to look closely to notice larval feeding damage. However, an easy indication of their presence is the light tan/brown colored moths, which are the adult stage of the pest. You may see them fly up as you walk through your lawn or if you disturb a nearby bush. The moths do not cause any damage to the turf, but they are depositing eggs, which will result in their offspring, the caterpillars, who do all the chewing damage.
The larvae are gray-green and have spots on each segment. The mature larvae can be up to 1 inch in length. Larvae will curl up in the soil during the day and feed at night. So if you happen to notice caterpillars feeding during the day, it’s probably not sod webworm. You will notice chewed notches along the leaf blade, holes in the leaf and even leaf blade skeletonizing. The older the larvae are, the more they will eat. Damage may start out as a ragged appearance in your turf, which can be hard to diagnose. However, if left unchecked, sod webworm can cause considerable injury to your lawn.
Sod webworm larvae. Photo courtesy UF/IFAS.
If you are uncertain of their presence you can always use a soap drench to flush out larvae. Mix 2 tablespoons of dish soap with 2 gallons of water and pour it over a damaged area (about 3 square ft.). The soap mixture will irritate the pest and bring them to the surface so you can easily identify them. If nothing appears in the area tested move to another damaged site and try again. Here is a link to a video that will give more information on identifying Tropical Sod Webworm.
Tropical Sod Webworm is considered a pest of all warm-season turfgrasses. However, St. Augustinegrass is most commonly affected. The best way to prevent a pest infestation is to use proper cultural maintenance practices for your lawn type. However, if the pest does appear, chemical control should be targeting the larvae stage of the pest. There are multiple products marketed to control lawn caterpillars. However, you may want to consider using B.t. (Bacillus thurengiensis), which is a bacterium that will only harm caterpillars and not bother beneficial insects that may be in your lawn. For more information you can contact your local extension office.
by Julie McConnell | Sep 2, 2014
Purple passionflower
Gulf Fritillary caterpillars have a voracious appetite for purple passionflower vine Passiflora incarnata! This native vine is a host for the Gulf Fritillary Butterfly Agraulis vanilla larvae, is easy to grow, and readily available in garden centers.
Like any other vine, it grows quickly and may spread across your garden, so keep this in mind when choosing a location. It prefers full sun, is drought tolerant, adapts to many soil types, and should be given support for twining tendrils. Purple passionflower has intricate purple flowers that are followed by the fruit called a maypop, which is another common name for this vine.
Gulf fritillary butterflies are primarily orange with some black and white markings. They prefer sunny areas and adults will feed on nectar from many different flowering plants. However, they are more specific about where they will lay eggs because the diet of the caterpillar is more selective than adults.
If you have purple passionflower in your landscape, look for tiny yellow eggs and orange caterpillars with black spikes to see if you have a backyard Gulf fritillary nursery. Plants may be totally defoliated by the hungry caterpillars, but healthy plants can tolerate the damage and should flush back out without difficulty.
by Sheila Dunning | Aug 19, 2014
Pine bark beetles are frequent pests of stressed pines in the southern United States. The five most common southern pine bark beetle species include three in the genus Ips. Ips beetles usually colonize only those trees that are already stressed, declining, or fallen due to environmental factors. Infestations may occur in response to drought, root injury, disease, lightning strikes or other stresses including flooding.
Ips calligraphus usually attacks the lower portions of stumps, trunks and large limbs greater than 4” in diameter. Early signs of attack include the accumulation of reddish-brown boring dust on the bark, nearby cobwebs or understory foliage. Ips calligraphus can complete their life cycles within 25 days during the summer and can produce eight generations per year in Florida. Newly-emerged adults can fly as far as four miles in their first dispersal to find a new host tree, whichever one is the most stressed.
Most trees are not well adapted to saturated soil conditions. With record rainfall this past April, the ground became inundated with water. When the root environment is dramatically changed by excess moisture, especially during the growing season, a tree’s entire physiology is altered, which may result in the death of the tree.
Water saturated soil reduces the supply of oxygen to tree roots, raises the pH of the soil, and changes the rate of decomposition of organic material; all of which weakens the tree, making it more susceptible to indirect damage from insects and diseases.When the ground becomes completely saturated, a tree’s metabolic processes begin to change very quickly. Photosynthesis is shut down within five hours; the tree is in starvation mode, living on stored starches and unable to make more food. Water moves into and occupies all available pore spaces that once held oxygen. Any remaining oxygen is utilized within three hours. The lack of oxygen prevents the normal decomposition of organic matter which leads to the production and accumulation of toxic gases such as carbon dioxide, methane, hydrogen sulfide and nitrogen oxide. Additionally, within seven days there is a noticeable root growth loss. Roots only develop when soil oxygen levels are at 5% -15%. Over time, the decaying roots are attacked by pathogens. The loss of root mass from decay and fungal attack leaves the tree prone to drought damage. After only two weeks of saturated soil conditions the root crown area can have so many problems that decline and even death are imminent.
When a tree experiences these anaerobic soil conditions it will exhibit symptoms of leaf loss with minimal to no new leaf formation. This usually appears two to eight weeks after the soil dries out again. Many trees will not survive, especially the more juvenile and mature trees. However, well established trees may still decline several years later, if they experience additional stresses such as drought or root disturbance from construction.
There is little that can be done to combat the damage caused by soil saturation. However, it is important to enable the tree to conserve its food supply by resisting pruning and to avoid fertilizing until the following growth season. Removal of mulch will aid in the availability of soil oxygen. Basically, it is a “wait and see” process. While water is essential to the survival of trees, it can also be a detriment when it is excessive, especially for drought tolerant pine species such as Sand Pine, which is prevalent throughout the coastal areas.
For urban and residential landscape trees, preventative strategies to avoid tree stress and therefore reduce the chances of infestation include the following:
1) avoiding compaction of, physical damage to, or pavement over the root zones of pines,
2) providing adequate spacing (15-20ft) between trees,
3) minimizing competing vegetation beneath pines,
4) maintaining proper soil nutrient and pH status and
5) limiting irrigation to established pine areas.
When infested trees are removed, care should be taken to avoid injury to surrounding pines, which could attract the more harmful pine bark beetle species Dendroctonus frontalis, the Southern Pine Bark beetle.
There is no effective way to save an individual tree once it has been successfully colonized by Ips beetles. In some cases, the application of an approved insecticide that coats the entire tree trunk may be warranted to protect high-value landscape trees prior to infestation. UF/IFAS Extension can assist with recommendations.
