(Pulvinaria delottoi and Pulvinariella mesembryanthemi)
The two insects that attack ice plant are a serious problem in home gardens and in highway plantings along the California coast. They damage and kill plants by sucking the sap from the leaves and stems. Both scales feed actively year round, but cause much less damage in the winter. The females mature and lay their eggs in white sacs from February to May and August to October. The eggs are spread from plant to plant by the wind. The fall generation causes the most damage because the plants are already under stress from the summer heat and dryness. For more information about scales, see Cottonycushion Scales, Wax Scales.
These pests are very difficult to control. Once the plants have turned reddish purple, it is too late to spray. Discard them and plant new ones. For mildly infested plants, treat with malathion or acephate, mixed with a summer oil spray. Do not spray when the white sacs are first present, because the eggs are protected. Spray shortly afterward, when the young crawlers have hatched and begin feeding. For best control, spray both the upper and lower surfaces of the plants. Beetles and wasps have been very successful in keeping the scales under control on highway plantings.
Plant Care for Mesembryanthemum