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Insect Problems in the Heat of Summer

Insect Problems in the Heat of Summer

Florida soft scale

Florida soft scale. Photo credit: UF/IFAS.

Scale insects are one of the most serious problems homeowners face on ornamentals this time of year.  The most common are armored scale, soft scale, and mealybugs.   They cause damage by sucking plant fluids from the leaves, stems, and sometimes roots.  Some species feed on the underside of the leaves which can appear as yellowing spots or chlorotic lesions.  Heavy infestations can cause extensive leaf yellowing, premature leaf drop, branch dieback, and plant death.

The life cycle starts when the eggs are laid beneath a waxy covering or beneath the adult female.  After the eggs hatch two to three weeks later, the nymphs (crawlers) move around the plant until they find a suitable feeding site.  Crawlers then insert their straw-like mouthparts into the plant and begin to feed and grow.  The male often develops wings and flies to locate a mate.

Armored scale nymphs. Photo: UF/IFAS.

Armored scale nymphs. Photo: UF/IFAS.

Armored scale is distinct from other types of scales because they secrete a waxy covering over their body that is not attached to the body. The scale lives and feeds under this covering ranging 1/16 to 1/8 inch in size. They can be any color or shape, depending on the species. Armored scale does not produce honeydew.

Armored scale. Photo credit: UF/IFAS.

Armored scale. Photo credit: UF/IFAS.

Soft scale also secretes a waxy covering but it is attached to the bodies. Soft scales vary in color, size, and shape.  They are circular shaped and range from 1/8 to ½ inch in diameter. Because they consume so much plant sap, they excrete a lot of sugary liquid called honeydew. Honeydew is the sticky liquid found on the leaves.

Mealybugs. Photo credit: UF/IFAS.

Mealybugs. Photo credit: UF/IFAS.

Mealybugs are soft bodied insects that are often covered with cottony white filaments.  They are 1/8 inch in size and feed on all parts of plants.  Injured plants have discolored, wilted, and deformed foliage.

Sooty mold is caused when mealybugs and soft scales excrete large amounts of honeydew which provides an excellent medium for the growth of the black fungus.  Sooty mold is not only unattractive; it slows down the growth of the plant as it interferes with photosynthesis.  Over time, with the control of the insect population, the sooty mold will weather away. Ants can also play a big factor in controlling sooty mold as they will feed on the honeydew.

Sooty mold. Photo credit: UF/IFAS.

Sooty mold. Photo credit: UF/IFAS.

To control scale and mealybugs, avoid over-fertilizing and monitor your plants often. If the infestation becomes over-bearing, spray a fine mist of Horticultural Oil on the foliage. Avoid spraying in the summer heat because of damaging foliage. Other chemicals that can be used if necessary are Sevin dust and Malathion.

 

The Smart Approach to Pest Management

The Smart Approach to Pest Management

When talking about pest issues in the landscape, green industry professionals often refer to IPM or Integrated Pest Management.

Chinch bug damage to St. Augustinegrass.  Photo: Julie McConnell, UF/IFAS

Chinch bug damage to St. Augustinegrass. Photo: Julie McConnell, UF/IFAS

So what is IPM and why should it be used?

IPM is a combination of methods used to manage pests that has the least harmful effect on non-target organisms and the environment.  The four categories of IPM are:

  • cultural practices
  • biological control
  • mechanical/physical
  • chemical control

There is not one perfect IPM plan for all landscape situations, but there are some key components to help develop one for any situation.

  1. Prevent pest problems – choose the Right Plant for the Right Place! Proper planting technique, choosing resistant cultivars, and good maintenance all contribute to overall health and can influence how likely plants are to survive disease, insect, or weed invasions.
  2. Scout for pests/damage – understand what pests are likely to target common landscape plants. For example, St. Augustinegrass is susceptible to attack by chinch bugs; know what to look for to spot an infestation early.
  3. Accurately identify the pest – it’s okay to ask for help with this! Your county extension office is a great place to start for both identification and control recommendations.  Many times treatments are applied for the wrong pest and that is a waste of your time and money and it can make it harder to get a correct diagnosis.
  4. Follow control action guidelines – have a plan in place for threshold tolerance. How many pests/amount of damage is okay before
    Chinch bug nymph. Photo: Julie McConnell, UF/IFAS

    Chinch bug nymph. Photo: Julie McConnell, UF/IFAS

    action is taken?  What action will you take?  Use least toxic methods first and combine the four methods listed above.  If using chemicals, know how they work (mode of action) and be sure to rotate properly to prevent resistance.

  5. Evaluate and revise – continued scouting for pests will indicate if the method is working. Keep records so that you can make changes that will increase effectiveness.

If you are interested in learning more about Integrated Pest Management, visit the IPM Florida website .

New Resource for IPM of Rose, Camellia and Other Major Shrubs

New Resource for IPM of Rose, Camellia and Other Major Shrubs

ipm guideA new IPM guide is making it easier to grow five common southeastern shrubs. Growing five southeastern shrubs is now easier thanks to a free, new IPM resource from the Southern Nursery IPM Working Group.

IPM for Shrubs in Southeastern U.S. Nursery Production is a compilation of Integrated Pest Management (IPM) information for five major shrubs in nursery crop production in the southeast. This 175 page book covers sustainable management for insects, mites, diseases, and weeds for these shrubs, as well as nursery production information. This IPM resource was developed for nursery growers although professional landscape managers and collectors of these plants also will find the information valuable.

Individual chapters cover abelia (Abelia spp.), camellia (Camellia spp.), shrub rose (Rosa spp.), blueberry (Vaccinium spp.) and viburnum (Viburnum spp.). Each chapter provides comprehensive information on the species, primary cultivars and their nursery production. Major pests, diseases, weeds and abiotic disorders are presented for each genus along with sustainable management methods and tables listing labeled pesticides and fungicides by mode of action and site. An additional chapter discusses weed management in shrub production. Future volumes covering additional shrubs are anticipated.

Edited by Clemson University’s Sarah A. White and University of Tennessee’s William E. Klingeman, this free guide was developed by the Southern Nursery IPM Working Group, including University of Florida NFREC’s Gary Knox and Mathews Paret. The award-winning, multi-disciplinary group is composed of experts from universities across the southeast. This group formed in 2008 to develop and deliver educational programming to the southern U.S. nursery industry and Extension personnel. The team recently won the 2014 Bright Idea Award from the Friends of Southern IPM and Southern IPM Center.

This resource joins the tree IPM book previously released by this group, IPM for Select Deciduous Trees in Southeastern US Nursery Production. The tree IPM book is similar to the new resource in that it contains IPM information for insects, mites, diseases, and weeds of nine major tree crops as well as production information. Individual chapters cover birch (Betula spp.), cherry (Prunus spp.), crapemyrtle (Lagerstroemia spp.), dogwood (Cornus spp.), chinese elm (Ulmus parvifolia), magnolia (Magnolia spp.), maple (Acer spp.), oak (Quercus spp.) and redbud (Cercis spp.).

Both books can be downloaded free through iTunes (http://www.apple.com/itunes/) or each chapter is available as a free pdf through the Southern Nursery IPM Working Group website, http://wiki.bugwood.org/SNIPM. A limited number of hardcopy books were printed and distributed to authors. Thanks to the Southern Region IPM Center for their generous support to make this resource possible!