Plant and Insect Diagnostic Clinic Update – March 30, 2018

The following are highlights and updates about samples and questions recently received in the Plant and Insect Diagnostic Clinic. Visit the PIDC's Facebook page for updates and more pictures. For more information on a particular disease or insect problem listed, follow the article cited.


San Jose scale on apple -  San Jose scales overwinter as nymphs beneath the body of the female. As weather warms they crawl out and settle on a part of the plant and begin feeding. Branches can become heavily covered in scales and appear sort of warty. Young scales can settle on the developing fruit as well, usually on the blossom end. The apple will have halos around the scales.



Hide beetle
Adult hide beetle.

Hide beetle – hide beetles are a close relative of the larder beetle.  The larvae feed on dead animals, dead insects, feathers, leather and taxidermy mounts.  If large populations are present in chicken or swine barns they can cause structural damage to the wood.  Larvae tunnel into wood in order to find a safe place to pupate and many larval tunnels on support posts can hurt the structural integrity.  Click here for more details.


Face flies – face flies occasionally overwinter in the attics and wall voids of homes.  Face fly larvae feed in manure and can be a problem for livestock as the adults feed in secretions from eyes, mouth and nose.  In homes they are a nuisance and will not survive long.  They look very similar to house flies.  See our online article for more details.


Pine tortoise scale on scotch pine - The scales produce large amounts of honeydew (scale excrement) leading to sooty mold growth.  Overwintering eggs will begin hatching in June. Eggs hatch into a stage called the crawlers. The crawlers are small and they move around on the branches seeking a suitable spot to feed. They feed by inserting straw-like mouthparts into the plant. Once they have found a good location they remain permanently and grow into the larger scale insect that can be easily seen on the branches. 



Sooty mold on pine.
Sooty mold is an indicator of a pine tortoise scale infestation.

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