You are hereThe Landscape Alerts
The Landscape Alerts
Tea scale is the most serious insect pest of flowering camellias. Tea scale also attacks hollies, citrus and the tea plant (Camellia sinensis) as well as a few other plants.
Tea scale is a small insect that attaches itself to the leaf and sucks plant juices. Adult female tea scales are about 1/10 inch long and are covered with a hard brown cover. The male scales produce white waxes that cover their bodies. In heavy infestations, these white waxes make the underside of the leaf appear cottony. Affected leaves will develop yellow blotches on the upper surface. Heavily affected plants may be thin and unsightly and have fewer blooms.
In the spring, the next generation of scales hatches from eggs and move to find succulent leaves. These young, mobile scales are yellow and called ‘crawlers’. The scales attach themselves to the underside of leaves, begin feeding and develop their waxy, protective covers.
The timing of the first generation of crawlers is important since this is the best time of year to treat tea scale with insecticides. The time of emergence of the first generation of crawlers is dependent upon temperature and can vary greatly from year to year. For example, the first emergence of tea scale in Athens, GA has been as early as the first week of February (1999) and as late as the first week of May (1997). March and April are the most typical months for emergence in Georgia.
Tea scale crawler emergence timing for your area can be estimated based upon the time of flowering of certain plants. Tea scale crawler emergence occurs about the same time as the beginning of bloom for honeysuckle or tulip poplar, the time of 50% bloom for Chinese wisteria or sugar maple or when the weeds henbit and chickweed are blooming. Begin first crawler sprays for tea scale when you see these events.
Another method of timing crawler sprays is by looking for the crawlers themselves before spraying. Place pieces of double sided sticky tape on small stems. The sticky tape will capture the crawlers as they emerge and make them easier to see. Begin sprays when you find crawlers stuck on the tape.
There are several generations of tea scale in Georgia each year. Female scales lay eggs for several weeks and these eggs hatch continually. Later in the season, landscapers may find all stages of the tea scale life cycle on the plant at the same time.
Several factors make tea scale control difficult:
- Tea scale infestations often develop on the interior of the plant and may not be noticed until the infestation is heavy.
- It is difficult to get sprays into the interior of the plant and on the underside of the leaves where most tea scales are found.
- The scale’s waxy covers make adult scales very difficult to control with pesticides. Crawlers are much easier to kill but pesticide application must be timed to crawler emergence.
For best control:
- Adult scales are very resistant to insecticides. Time insecticide treatment to correspond to the first emergence of crawlers. Use the information mentioned earlier under ‘Tea scale crawler emergence timing for your area’ to decide when to begin treatment.
- Apply insecticides so that they cover the bottom surface of the leaves.
- Repeat treatments may be needed with heavy infestations. Select insecticides from the Pest Management Handbook.
- Prune out heavily infested branches. Remove 2 to 4 inch long non-flowering branches on major limbs inside the plant since these can harbor scale.
- Thin the plant by removing selected branches. This can improve control by increasing air circulation and improving pesticide penetration into the plant.
- Light to moderate infestations can be treated with oil sprays. Oil sprays are effective against crawlers and adult scales. There are two types of oil sprays – those that are used in the cooler weather of spring and fall and the highly purified oils that can be used during the growing season. Read and follow all label directions to select the correct oil spray.
- Cover scales very well when using oil sprays since oils work by smothering the insect.
- Beneficial insects help control tea scale - small parasitic wasps, convergent lady beetles, green lacewings and spiders. Preserve these natural enemies by using oil sprays instead of traditional insecticides and only spraying when absolutely necessary.
Heavy tea scales infestations may require 2 - 3 years for control. The bodies of the tea scale will usually remain on the plant after they die. Examine plants carefully after treatment to determine the level of control. Living tea scale will be moist when crushed while dead scale will be dry.
Annual bluegrass (Poa annua L.) is a troublesome winter annual weed in residential turf. Compared to most turfgrasses, annual bluegrass has a lighter green color, coarser leaf texture, and produces unsightly seedheads.
Annual bluegrass seed germinates throughout the late-summer and early-fall once soil temperatures drop below 70° F. Seedlings grow and mature in fall, overwinter in a vegetative state, and produce seed in spring. A second germination can occur in late-winter as soil temperatures rise and the days become longer. Annual bluegrass is a prolific seed producer and individual plants may produce hundreds of viable seed, even when closely mowed. Annual bluegrass flowers over several months in spring and produces seed that may remain dormant in soil for years before germinating. Annual bluegrass often dies from summer stresses but may survive in protected sites that receive irrigation. Controlling annual bluegrass in mid- to late-spring in residential lawns can be difficult.
Up until mid-February (when the bermudagrass was fully dormant) applying a glyphosate containing product (e.g. Roundup) was an option for postemergence annual bluegrass control. Even then, care must be taken not to "overdose" the weed and harm the bermudagrass. It is too common that homeowners over-spray the weed with glyphosate and some herbicide moves deep into the bermudagrass canopy where it contacts green bermudagrass stolons near the ground. Any green part of the plant in the bermudagrass can absorb the glyphosate which can damage the plant. It is now too late and risky to consider spraying glyphosate to control annual bluegrass in dormant bermudagrass. While bermudagrass may still look "completely" dormant it is starting to greenup and the application of glyphosate during greenup can damage the turf.
Unfortunately, there are few selective herbicidal options for homeowners to control annual bluegrass at this point in the season. In bermudagrass and zoysiagrass, if the annual bluegrass population is bad enough the best option is to consider hiring a professional lawn care operator and request the annual bluegrass be treated with either Revolver (foramsulfuron) or Monument (trifloxysulfuron). Both herbicides are applied at a low use rate and are expensive. For the homeowner, this makes them difficult to correctly mix and cost prohibitive. Although they are not restricted use pesticides, these herbicides are available through professional lawn care outlets and are not found in retail "big box" stores or in ready-to-use (RTU) formulations.
Neither of these herbicides is labeled for use on centipedegrass or St. Augustinegrass. In centipedegrass and St. Augustinegrass, atrazine containing products (e.g. Scotts Bonus S) are an option but large annual bluegrass grass plants are difficult to control with a single application.
The weed is an annual cool-season grassy weed that will die-out in a couple months as temperatures warm. For now, having patience and tolerance maybe the best option. Plan for next winter and spring. Begin with good turfgrass cultivation this summer. For example:
- Deep and infrequent irrigation encourages turfgrass root development which improves the ability of the lawngrass to compete with weeds.
- Identify and alleviate soil compaction since annual bluegrass prefers compacted soils. For rapid recovery and improved vigor, core aerifications should be performed during the active growth period of warm-season turfgrasses.
- Mow the lawn at the appropriate height for the grass species. Lower mowing heights may stress turf and reduce its ability to compete with annual bluegrass. For proper mowing height recommendations, visit www.GeorgiaTurf.com.
- Lastly, implement a preemergence herbicide program in late-summer to help control the seed that were deposited this season.