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Pests of Apple :: Major Pest :: Cottony Cushion Scale


3.  Cottony Cushion Scale:  Icerya purchasi (Margarodidae: Hemiptera)


Damage symptoms: Sap sucking by nymphs and adults causes yellowing of leaves, Reduced tree vigor. If infestations are heavy, leaf and fruit drop can occur along with twig dieback.


Bionomics: Female with a cottony ovisac. Crawler nymph pinkish with long antenna and group of hairs. The body of the female cottony cushion scale is orange, yellow, or brown. Elongated, fluted, white cottony egg sac is attached to its body. The egg sac contains 600 to 800 red eggs. Females usually occur on twigs. Eggs hatch into crawlers in a few days during warm weather and in 2 months during winter. The crawlers are red with black legs and antennae. They settle along leaf veins and begin to produce the white cottony secretion. Immature scales look reddish for a short period of time. Second-instar nymphs settle on twigs and leaves, usually along leaf veins. Third-instar scales move to branches and trunks. Adults may be found on branches or on the trunks of trees. The minute, red, winged male is rarely seen. Two to three generations a year. Unlike most other scales, it retains its legs and its mobility throughout its life. Cottony cushion scale completes its life cycle in 3 months during warm weather conditions.





Conserve natural enemies by controlling ants and dust and by avoiding the use of persistent insecticides. Keep ants out of trees and shrubs by banding the trunks with sticky substances or by using ant baits
Look for the vedalia beetle and its red eggs and larvae on top of cottony cushion scale scale egg sacs or the beetle’s pupal cases. Also, inspect female scales for parasitic fly Cryptochaetum icerayae s emergence holes and pupal cases to avoid insecticides.
If natural enemies are absent, spray malathion 50 EC 3.0 L or acephate 75 SP 2.0 kg in 1500 -2000 L of water per ha
Do not apply imidacloprid for cottony cushion scale as it is very toxic to vedalia beetles.