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Beating Pests with Plant Chemicals

Beating Pests with Plant Chemicals

It would seem that landscapes are filled with pests ready to devour our favorite plants. We can often see evidence of pest damage in the form of leaf curls, stippled leaves, or chewed holes in foliage. How do plants survive with all the pest threats without intervention from people?

Many plants have their own alert system to help manage a plant-feeding insect attack. When tissues are damaged by plant feeders, the plant releases volatile chemicals that serve as signals for many beneficial insects. Predators such as lady beetles, lacewings, and predatory bugs ‘pick up’ the chemical signals and fly to the injured plants to find their prey.

Ladybeetle larvae will eat many soft-bodied pests.

Ladybeetle larvae will eat many soft-bodied pests.

An interesting part of this occurrence is that the release of chemicals by one plant can stimulate other surrounding plants to build up their chemical defenses against future pest feeding.

The key lesson for all gardeners is that there are many natural processes going on without our knowledge. Instead of immediately applying a broad-spectrum insecticide at the earliest sign of pest feeding on a plant, give the predators a chance to provide you with a free and environmentally sound form of pest control.

Getting to Know Your Backyard Pests

Getting to Know Your Backyard Pests

Deer are known to eat daylilies in the landscape. To prevent browsing, choose other plants or create a barrier with deer fencing.

Deer are known to eat daylilies in the landscape. To prevent browsing, choose other plants or create a barrier with deer fencing.

Any seasoned gardener knows that even a well maintained garden will eventually face a pest issue. Pests come in all shapes and sizes and may include weeds, disease, insects, moles, rabbits, birds, and deer. Although some gardeners may invite wildlife into their gardens when that adorable deer eats your prized hydrangea it tends to lose the cuteness factor.

Regardless of what type of pest issue you are facing, the only way to establish a successful control program is to correctly identify and understand some basic things about the pest. Incorrect assumptions or misidentification can lead to taking the wrong action and may even cause more harm to plants.

Some things to know about your pest (after identification):

  • Preferred host or target plant – diversify landscapes to minimize susceptibility to each pest.
  • Feeding/damage caused – is it just aesthetic or will it cause long-term harm?
  • For rapidly reproducing pests such as insects or fungi, what is the timing of new generations? For example, if you eliminate adult insects expect that eggs are waiting to hatch – you need to know when to retreat.
  • What natural enemies might help reduce populations and how can they be preserved?
  • Be sure to match control methods with pest behavior and activity. For example, if you want to use an insecticidal soap on azalea lace but you need to know that they feed from the underside of the leaf in order to properly coat them with the product.

Take the time to get to know the pest in your backyard and management efforts will be much more effective. For help with identification and control, contact your local extension office.

Design Your Own Butterfly Garden

Design Your Own Butterfly Garden

Butterflies are not only beautiful to look at in your landscape; they serve as important pollinators and indicators of the health of our environment. Attracting them to your garden and incorporating some features to get them to stay and make it their home involves a little planning ahead of time for optimum results.

Queen butterfly. Photo credit: Milt Putnam, UF/IFAS.

Queen butterfly. Photo credit: Milt Putnam, UF/IFAS.

Choose a location that provides some protection from wind. Trees and shrubs that provide wind protection also serve as a safe harbor from rain and predators. The garden should be mostly sunny with some part sun areas. Ensure that any new plantings have access to a convenient irrigation source so they can be successfully established and maintained in good health.

Now you’ll need to choose the plants. Adults feed on the nectar of many flowering trees, shrubs, perennials, and annuals and, fortunately, there are usually many choices that will meet your site requirements and your taste preferences. In order to keep the butterflies in your garden, certain plants need to be available to serve as host plants for their young. Determine which species of butterfly is common in your area and that you want to attract. Most species have very few plants on which the caterpillars can feed so those host plants need to be chosen wisely. Determine whether any of the plants you already have are host plants and they can be integrated into your butterfly garden. For example, cassia is a host plant for the Cloudless Sulphur and citrus is a host plant for the Giant Swallowtail.

In choosing your nectar plants, select those that are native or Florida-Friendly as they are lower maintenance, giving you less trouble in the long run. Choose plants that have flowers in a variety of color, size, and shape. Different butterflies like to feed at different elevations, so choose trees, shrubs, perennials, and annuals of varying heights. In order to have nectar available throughout the time when the butterflies occur, include plants that bloom at different times of the year. And include some plants that bloom from spring to late fall, like pentas or moss verbena.

Larger plants should be placed in the background with smaller plants layered in the foreground.  When you plant smaller annuals and perennials, place them in masses to better attract the butterflies.  Consider placing host plants in an area that is in close proximity to the nectar plants, but in an area of your garden that is not a focal point. Host plants can get quite ragged looking from hungry caterpillars!

Good maintenance practices will enhance the health of your garden. Regular fertilization and irrigation if needed will help keep your plants in bloom and healthy; healthy plants are less susceptible to disease and pests. Avoid pesticides as they may harm the very creatures you are trying to attract. Never use Bt or systemic pesticide.  If you must, target a pest with lower risk oils or soaps and then only treat the affected plants. Lastly, be aware of beneficial insects that will help you achieve satisfactory control of a pest.

Now that your plants are placed there are several things to do to make your butterfly garden complete. Add a spot where water can puddle on the ground for the adult butterflies to drink. They require minerals from the soil that get dissolved in the water. Also add a rock or log in a sunny spot where butterflies can rest and sun themselves. And consider placing a comfortable place for you to sit and enjoy the beauty of your garden and its inhabitants!

For more information:

Butterfly Gardening in Florida

 

Southern Purple Mint Moth

One very popular herb for the backyard garden is the evergreen Rosemary, Rosmarinus officinalis which serves as an attractive landscape shrub in addition to its culinary uses. Rosemary grows best in full sun and well-drained soils. When planted in the ground, rosemary can grow 4-5 feet in height and spread. Plants do have beautiful bluish flowers that form in late winter and early spring, providing nectar for bees.

Rosemary officinalis

Rosemary is generally a pest free plant but some gardeners may find damage resulting from an insect pest. Rosemary is one of the hosts for the Southern purple mint moth, Pyrausta laticlavia which will lay eggs on several plants in the mint family. Caterpillars feed on leaves along the stems which become matted with silken threads and frass from the insects. As a result of the feeding, leaves are not useable and plants do not look attractive. Heavy populations will stress plants.Rosemary damage_moth

Since rosemary is often used to flavor many foods, many people do not want to use an insecticide on the plant. One least toxic option that can be used safely on edibles is Bacillus thuringiensis. The product is specific for caterpillar management and safe for predators that may help manage some caterpillars.  Homeowners may also physically remove caterpillars or prune out damaged stems on larger plants.

Beetles to the Rescue

Air-potato-with-bulbil-inset_largeAir potato (Dioscores bulbifera) is a perennial, herbaceous self-twining vine that can grow over 60 feet in length, enabling it to climb over and smother many native plants. The Florida Exotic Plant Pest Council (FLEPPC) lists air potato as a Category 1 invasive plant, which means that it has disrupted natural communities and ecological functions by displacing native plant species.

In 2012, a leaf feeding beetle (Lilioceris cheni) was introduced into South Florida from China for biological control of air potato. Although it is too early to determine any potential long-term impacts, the initial results have been promising. The larvae and adults of the air potato leaf beetle feed on the leaf tissue and occasionally the bulbils. The damage to the growing tips of the plant have dramatically reduced its ability to cover native vegetation. Extensive damage to air potato was evident within three months after the first release. Additionally, testing by scientists at the USDA/ARS Invasive Plant Research Laboratory in Fort Lauderdale concluded that the beetle will not complete development on any other plant found in Florida.air_potato_leaf_beetle09

airpotatobeetleThe female air potato leaf beetle lays an average of 1,200 eggs, which develop into larvae in about four days. The young beetles skeletonize the air potato leaves for the next eight days and then pupate into foam-like cocoons. Clumps of cocoons fall to the ground and the adult beetles emerge 13 to 16 days later. There can be a new generation of air potato leaf beetle every month while the weather is warm. For the winter, the adults hide in leaf litter and wait for spring.

 

The question now is: “How well will they survive through a longer, colder Northwest Florida winter?”. USDA scientists, UF Extension agents and citizen scientists in Bay and Okaloosa County hope to find out. Earlier this month, June 2015, air potato leaf beetles from the Hayslip Biological Control and Research and Containment Laboratory in Ft. Pierce were released into areas containing air potato. They will be monitored over the next year. Look for an update next summer.

Conenose and Kissing Bugs: Necessary, But Not Fun If Contacted

Conenose and Kissing Bugs: Necessary, But Not Fun If Contacted

Eastern Blood-sucking Conenose bugs are found in and around plant where they are hunting for insects.

Eastern Blood-sucking Conenose bugs are found in and around plant where they are hunting for insects.

While it is not exactly a jungle “out there” in the landscape, there are some occasionally encountered insects which can inflict pain. The kissing bug and the blood-sucking conenose are native insects which are best not physically encountered.

The native kissing bug, Triatoma sanguisuga, is part of the assassin bug family. This insect is commonly called a kissing bug because it targets the soft tissues around the mouth of mammals as a feeding site.

As if being in the assassin bug family is not bad enough for its image, this pest’s South American cousin is responsible for inoculating victims with Chagas disease. Chagas disease, a protozoan infection, has occurred in some western states but not Florida.

The bloodsucking conenose, in assassin bug family too, is found in north Florida. It is a dark brown, winged bug, 3/4 inch long, with the edges of its abdomen alternating in light and dark colors.

They have a slender, straight beak with piercing-sucking mouthparts. The antennae are inserted on the side of the head between the eyes and the end of the beak.

They are rarely seen during the day, instead hiding in leaf litter and other debris near their intended host. Birds apparently consider them quite tasty and are easy targets for avian predators.

Kissing bugs primarily feed at night on the blood of sleeping animals, such as raccoons and opossums which burrow in the vicinity.

Their life cycle varies considerably depending on temperature, humidity, and availability of hosts. Females lay one egg at a time, up to five eggs each day.

Problems arise when these insects encounter humans. If this creature enters a home or dwelling, its nocturnal habits make humans easy prey.

The bloodsucking conenose will enter into a home by crawling through cracks in the foundation, torn window screens, or other structural flaws or inadequacies. Many times they enter by simply clinging to a domestic pet or to the clothing of an unaware person. Once indoors, they are found in bedding, cracks in the floors and walls, or under furniture.

Most bites from conenose bugs are rarely felt. However, some can be quite painful and infection can occur if the wound is scratched and contaminated.
The assassin bug, the entomological cousin of the kissing bug, usually is encountered in foliage and has little inclination to enter homes. It is capable of delivering a nasty surprise to the unsuspecting gardeners who disturb this ambush predator.

The green leaves and pretty flowers are an ideal habitat for the assassin bug and the kissing bug to put the bite on ideal menu selections. This is something to keep in mind this spring when enjoying the panhandle Florida’s great outdoors.

To learn more about the assassin bug or the kissing bug, contact your UF/IFAS Extension Office.