Species Acalitus phloeocoptes - Almond and plum bud gall mite

Plum bud gall mite

Acalitus phloeocoptes (Nalepa) 1890

"On almond the mite produces permanent irregular galls of various sizes around buds. It also deforms fruit spurs. The entire physiology of the attacked almond tree becomes upset: fruit buds fail to form, trees lose vigor, and damage appears to be progressive, and irreversible. This results in almond trees dying in 3 to 6 years. A physiological strain of almond grows in Lebanon which is immune to attack by A. phloeocoptes.

"On plum, small subspherical galls of between 1.3 and 1.8 mm in diameter grow around buds. These galls may be single, or grouped around the buds. The galls become woody, and deform fruit spurs. But in contrast to almond, plum trees often recover from mite attack and show no lasting injury."(1)

An invasive species in the US, "This species ranges extensively throughout southern and central Europe, and occurs in Asia minor. It has also appeared in the eastern United States." (1)

From an article in The Daily Garden, "As of January 2019, it made its way to California, threatening tens of thousands of plum, pluot, almond, apricot, and many other fruit and nut trees." Gall images from this infestation are posted.

From a Powerpoint presentation about this species by Jim Amrine, Prof. Emeritus, West Va. Univ., "My distribution for this mite is: Algeria; Armenia [3499]; Austria?; Bulgaria; (Gansu) China [5562, 5162]; (Moldavia) Czech Republic; Croatia; Finland; France [6996]; Germany; Greece; Hungary; Italy; Israel [2213], Krasnodarskiy Region [3499]; Kyrgyz Republic; Lebanon [2213]; Moldavia [3499];Morroco [5062]; Portugal; Slovenia; Syria [2213]; Turkey [7701]; Ukraine [3499]; (California, Montana, Ohio [2777,2780], Washington) USA; [Yugoslavia]. We do not know who found it in CA, MT, or WA, or when; somehow, failed to document the distribution."

Kyle Beucke, the primary state entomologist for California, has the following advice:

"As we are currently trying to determine the distribution of this mite in California, I would advise anyone finding suspect plum bud gall mite galls to report them to their local county agricultural commissioner’s office. It is important that infestations of plum bud gall mites are promptly reported and that specimens are collected and identified by California Department of Food and Agriculture personnel. Galls with live mites should not be sent through the mail."

Also, Jim Amrine, a specialist working on Eriophyoidea, is working more broadly to find all US locations where this mite has been found. Please notify him too of any suspected sightings.