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Macadamia Felted Coccid

Eriococcus ironsidei

Insectalso: Felted coccid, Eriococcus ironsidei, Macadamia felted scale

A tiny felted scale insect, related to mealybugs, that has become a serious invasive pest of macadamia. It encrusts stems, leaves, and nuts in large numbers, draining sap and causing yellow spotting, dieback, and dropped flowers and nuts.

🔎 How to spot it

The insect is small and covered in a whitish, felt-like waxy sac, settling in clusters on the bark of stems and branches, on leaves, and on the husks of nuts; heavy infestations look like a grayish-white felting on the wood. Yellow blotches on leaves around feeding sites and a general off-color, thinning canopy are early signs. The mobile young, called crawlers, spread the infestation.

🥀 Damage it causes

Sap feeding causes yellow spotting and chlorosis of leaves, branch dieback, and premature drop of flowers and young nuts, and heavy, sustained infestations reduce nut yield sharply and can kill large portions of, or whole, trees. As an invasive pest with few natural enemies in new areas, it can build to damaging numbers quickly.

🛡️ Prevent it

Avoid moving infested plant material, which is how the pest spreads to new orchards, and inspect for the felted clusters and yellow leaf spotting so build-ups are caught early. Prune and thin the canopy to open it up, which has been shown to cut coccid numbers and improves spray coverage, and keep trees vigorous.

🧯 If it is already here

Horticultural oils and insect-growth-regulator insecticides are the main tools, aimed to reach the sheltered scales and timed against the crawler stage; thorough coverage of encrusted bark is essential. Canopy pruning lowers populations, and classical biological control with the host-specific parasitoid wasp Metaphycus macadamiae is being used to suppress it where established.

💡 Good to know

The felted, mealybug-like waxy sac sets it apart from the harder, smoother scales, and the felting on bark plus yellow leaf spots is the combination to look for. Not moving infested material is key to keeping it out of clean orchards.

🌱 Plants it attacks

52 plants in the library can be attacked by this pest

For educational and informational purposes only. Pest control advice is general guidance drawn from university cooperative extension sources; always identify a pest positively and read and follow the label on any product before use, especially around food crops, children, and pets.