The end of summer brings many different problems to our landscapes. The heat and humidity plays havoc to tender annuals and perennials, tender shrubs and dogwoods. Extended periods of rain will cause root rots on poorly drained soils while periods of drought will put plants in sandier soils under moisture stress.
Along with these environmental problems, there are several common insects which will begin to cause unwanted damage to some of our prized shrubs. The most visible of these insects will be the bagworm. This insect is a general feeder and will attack many plants in our coastal landscapes including junipers.
Bagworms are easily identified by the numerous spindle-shaped sacks or bags hanging down from twigs and branches. During the summer months, these bags will contain a dark-brown, shiny worm. These worms will feed throughout the summer on your plants carrying their bag with them. This bag offers protection from birds. As summer ends, the male will turn into a small black-winged moth while the female remains wingless and in their bags. New eggs will be laid in the bags as the female drops to the ground and dies.
Control can be achieved by picking the bags off the infected plant during the winter and destroying them. Do not merely let them drop to the ground as the eggs will hatch and the worms will find their way back into the trees. This method is one of the best when the insect is just getting started. Plants which are heavily infested can be treated with one of several different insecticides that can be found at local gardening centers. Natural control can also be obtained by an application of Bacillus thuringensis or Bt.
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Another common late summer problem is the red-headed azalea caterpillar. This insect will devour azaleas at an alarming rate. They are generally black in color with yellow stripes. The head and feet are bright red, hence the name, and will bend backward with its head lifted when disturbed. As with bagworms, the red-headed azalea caterpillar is easy to control with common insecticides or organic methods.
Spider mites often invade our landscape plants as well as our vegetable gardens during the late summer, especially when the weather has been hot and dry. Spider mites are small critters that will feed on the cells of plant leaves causing a bleaching of plant leaves. Heavy infestations can cause a loss of vegetable plant productivity as well as a loss of ornamental plant vigor. Heavy infestations not treated can cause plant death over time. To treat for spider mites, a pest control product developed specifically for mite control called a miticide will be needed. Lite or summer horticultural oils are also very effective in spider mite control but care should be taken when temperatures are hot.
Several problems can also appear in our lawns during this time of year. Mole crickets, our worst turf insect problem, will usually begin to become evident during the early fall as the nymphs begin to grow. A late season insecticide treatment for mole cricket control will allow your lawn to enter winter healthy. Be sure the product you apply is labeled for both turf and mole crickets.
Finally, several patch diseases can crop up if rainfall increases before the first frost. Heavier soils that have poor drainage can benefit from fungicide applications. Again, the healthier your turf is going into winter stresses, the healthier it will be when greening in the spring. By taking the time to walk around your lawn and garden, you will be able to get a jump on these late season problems insuring quick and complete greenup in the spring.
Reach Debbie Menchek, a Clemson Master Gardener, at firstname.lastname@example.org.