Spider mites on continental temperate palms

[Phoenikakias]

Affected is a Brahea dulcis of mine (first three pictures) and a Washingtonia filibusta/robusta of a friend (rest pictures). How common is this? Another friend claims, that this was caused by extreme drought and heat. However neither of those spp is known to grow in places with high air humidity. Last year I had same problem with another Brahea (aculeata) and a Sabal (bermudana). Also Washingtonia filifera's habitats are groves inside the desert. Suffice to say, that I am quite intrigued and more so because I had never had before issues with spider mites on temperate, continental palms.  Aforementioned friend wants to explain those incidents through the widespreading of them from other, more tender and initially infested palms, which of course are absent in the desert). Truth is that both me and the owner of the Washingtonia are maintaining greenhouses in the garden and at least in my cold frame during August did take place a spider mite outbreak but none of the outdoor growing oceanic plants (Kentia, Chrysalidocarp us, Chambeyronia) was infested. I would like to read your comments on this matter.

 

 

 

[happypalms]

Mites love hot dry temperatures, dislike humidity and wet conditions. A regular spray program and rotation of different chemicals beats them. Predator mites work well or release lots of ladybugs 🐞. But a good hosing works wonders on the underside of the leaf.