| My Santa Ana tif has been decimated by pearl scale. I used Merit according to directions for 2 years with no improvement. I'm having a wedding in my backyard in Oct and thinking of hydroseeding with annual rye for some green. Everybody tells me to dig out 2 feet of dirt and resod. I have approx. 6000 sq. foot of lawn so this is not an option. What do you suggest? Thanks so much. Marilyn |
| I am copying an detailed article on Pearl Scale below, written by Sharon Dewey is a Certified Turfgrass Professional, a turfgrass troubleshooter and a Master Gardener with the University of Arizona Cooperative Extension, ad Dave Langston, Ph.D. is the Superintendent of the Arizon Maricopa Agricultural Center, an Extension Specialist in Entomology with the University of Arizona. PEARL SCALE OR GROUND PEARL AND YOUR LAWN By Sharon Dewey, Certified Turfgrass Professional, and Dave Langston, Ph.D. University of Arizona, College of Agriculture Pearl scale or ground pearl, refers to an insect that can be a problem for St. Augustine, Zoysia and Bermuda grasses. Hybrid Bermuda grasses are usually more affected than common Bermuda. As the name implies, an infestation will resemble miniature pearls. Scale insects secrete a whitish to brown substance that covers and protects their bodies, and are seldom larger than one-sixteenth of an inch. These insects suck the juices from plants, usually killing the root. The grass gradually weakens, turns yellow, then brown, thins and dies, and circular patches of dead grass will appear on the lawn. Damage will appear in the fall as the grass is going in to dormancy. These damaged areas will not recover the following spring when the grass begins to grow again. In late May and lasting throughout the summer, the majority of females emerge from their pearl scales and lay about 100 eggs in a waxy coat. In a few days the eggs hatch into crawlers, which attach to grass roots. They secrete a hard, waxy coating that becomes the next generation of ground pearl scale. Here are some tips on detecting pearl scale. 1. Dig at the edge of the damaged area that is next to an unaffected area. 2. Carefully dig down two to four inches. Try not to spread scale to unaffected area. 3. Look at the roots of unaffected area. 4. Pearl scale are obvious because of their contrasting color and their shape. 5. The insects are soft and can be easily squashed. 6. Be very careful with contaminated soil and the tools used to examine the lawn, as they can contaminate unaffected area. Controlling scale. Pearl scales are spread in infested turf and through the use of dirty equipment. Always wash the soil off shovels, trowels or other lawn and garden equipment after each use. Mowers are not likely to transfer scales unless they are very dirty. There are no chemical control methods that completely rid the lawn of pearl scale. However, there is some evidence that applications of soil acidifiers (these reduce soil pH), and/or the product Merit may help slow down the spread of pearl scale. The optimal time for treating a lawn with Merit is in late May when the females are emerging. 1. The best chance for control is early detection when the circular patches are small and manageable. 2. Carefully remove damaged patches one foot beyond the affected area and one foot deep. Then dispose of the affected roots and the surrounding soil. Pearl scales may withstand long periods of drought in the soil, and may still be alive after more than a year. So be very careful to avoid spreading them when replacing damaged turf. 3. Most of the pearl scale will be in the upper two to four inches of soil, but have been found as deep as grass roots grow, making control very difficult. 4. After removing affected portions of the lawn replace the contaminated soil. At this time you may want to treat with soil acidifiers and/or Merit and then re-sod or seed the area. 5. To enhance the penetration of soil acidifiers, make holes in the area to be treated before applying acid mixtures. Prevention. Proper maintenance helps prevent pearl scale infestations. Although rare, some lawns, particularly common Bermuda have been shown to grow out of an infestation when the lawn receives proper maintenance. Also, seeded Bermuda appears to be able to better withstand pearl scale, or at least the spots can be reseeded each year to cover the damaged areas. This is NOT a control method but merely hides the damaged spots. Maintenance tips: 1. Water deeply (eight to 10 inches), but only as often as to avoid wilt. 2. Fertilize every four to six weeks using a complete fertilizer such as a 21-7-14 blend. 3. Mow no more than the top one third of the grass, using a sharp mower blade. 4. Remove thatch if it is more than one-half inch thick. |
