Novelty phalaenopsis issues

[Sahil]

Hi everyone, i have been growing orchids for a while , for my phalaenopsis hybrids and novelties , i keep them under full spectrum 40 watt grow lights , grown mostly in bark and some in moss and bark mix . Warm temperatures from March to October (30-40⁰C depending on month) , cool temps from November to February (~12-24⁰).
I spray either thiophanate methyl/ kocide/ metalaxyl once a week for protection
All the complex hybrid phals and primary species are doing well but i am facing problems with some novelty phalaenopsis i recently aquired ,imported from Taiwan . They seem to get yellow chlortic rings or dots on the leaves which keep on progressing even with proper care/ventilation AND FUNGICIDE & BACTERIOCIDE SPRAYS.
No other plants in my collection het affected, only a few of the novelty phalaenopsis from Taiwan . Seems to me like a fungal infection
Mostly when this happens, when i spray the antibiotics the infection stops but the novelties are the only ones that repeatedly get affected , with same symptoms, same rate of progressing.
I once saw a video in you tube saying novelty phals from taiwan carry a fungus which remains dormant and activates in warm temperatures
Plants affected- phalaenopsis zhen min anaconda, phalaenopsis yaphon black swan , phalaenopsis lioulin amber × red lion , only the ones from Taiwan
Has anyone faced this problem? Are novelty phalaenopsis slightly weaker/problematic? I did observe they have pale lemony leaves as compared to the hybrid phals

[Dimples]

Novelty phals are also hybrids, they just have “fun/unusual” colors/shapes/etc., but they typically have a higher proportion of hot-growing species in their genetics.

Phals in general dislike dropping below 20C/70F, and phals with lots of hot-growing ancestors will struggle in temperatures under 24C/75F for extended periods. Adding a heating mat can help you in the cool season.

[Sahil]

Originally Posted by Dimples

Novelty phals are also hybrids, they just have “fun/unusual” colors/shapes/etc., but they typically have a higher proportion of hot-growing species in their genetics.

Phals in general dislike dropping below 20C/70F, and phals with lots of hot-growing ancestors will struggle in temperatures under 24C/75F for extended periods. Adding a heating mat can help you in the cool season.

Presently, the weather is hot and humid here , not sure why only some of the polychilos/warm growing phals got infections and other phals are all growing well..

[estación seca]

Perhaps there is a nearby agricultural department or university biology department that could examine the lesions under a microscope?