Pearl Scale treatment - Knowledgebase Question

Phoenix, Ar
Question by llbullard
April 30, 2009
Is there any treatment to kill pearl scale short of digging up entire lawn and replacing it?

Answer from NGA
April 30, 2009


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.

Hope this information helps!

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