Columns written by Greg Grant and a Smith Co. Master Gardener which have appeared in the Tyler Morning Telegraph, are posted here.
Tea scale gets its name from the tea that we drink, which is made from Camellia sinensis. Female scale insects are able to reproduce every one to two weeks, increasing the population exponentially.
Spray the entire plant, top to bottom, especially the underside of the leaves, with dormant oil, neem oil or horticultural oil. These are all very low in toxicity and do not leave behind any residue that harms beneficial insects. Contact insecticides can work, but are much less effective than oil treatments or systemic insecticides. However, including a contact insecticide with your oil spray does make it more effective. Systemic insecticide products also work well at this stage and control crawlers as well as adult scale insects. Imidacloprid (Bayer Advanced Tree and Shrub Insect Control and other brands) is a systemic insecticide that is effective against tea scale. It comes is available in both granular and liquid forms. When a very heavy infestation is observed, use both horticultural oils and imidacloprid. A two prong approach will provide best results. Only use the systemic insecticide when the plant finishes blooming, so no pollinators will be affected.
Dead scale insects turn a darker shade of brown or black and slowly flake off the underside of the leaf. Live scale insects are fairly moist, while dead ones are dry to the touch.
There are several generations of tea scale crawlers each year, so monitor your plants monthly to catch any new outbreaks. Catching the issue early is the best way to avoid heavy infestations. Heavily infested shrubs should be monitored and treated as needed, and may require several years of control. Pruning out heavily infested branches or leaves can help. Increasing air circulation within the plant helps to open the insects up to natural predators such as lacewings, ladybugs and spiders.
If your camellias are small or weak, a light application of a camellia-gardenia-azalea food this time of year is a good idea as well.
Most annual vines produce long twining stems, which need some help at least initially to begin their climb. Some examples include Black eyed Susan vine, Cup and Saucer vine, morning glory, Hyacinth Bean and gourds. These vines would all work well on a chain link fence or a trellis. A simple string trellis can be made by using nails or cup hooks on a wall and stringing twine or nylon fishing line between them in either straight lines or a zig zag pattern. To get your vine to start climbing you may have to help it along by dropping a string to the ground to let it latch on to or by using twist ties or lengths of old hosiery to guide your stems in the direction you want them to go. Bird netting or chicken wire also makes simple but effective trellises for twining vines. The leaners need a little more help getting started than the vigorous twiners, but once on their way they usually do well on their own.
Several perennial vines are more adhesive and tend to be much woodier. Trumpet creeper, Evergreen bittersweet, climbing hydrangea, English ivy and Japanese hydrangea vine all have adhesive aerial roots that will either adhere to solid surfaces or wedge themselves into cracks and crevices. This can cause damage to some surfaces like brick or stone. It is best to put a trellis in front of the wall so the vine will stay off the wall itself. Most vines bloom in spring or summer, but some come on a little later. These include Sweet autumn clematis, which blooms in late August around here, morning glories and some bougainvilleas. There are even winter blooming vines such as Chinese jasmine and Carolina Jessamine.