Brown Spots on Gymno Spegazzini

[hendryterok]

All,
Im having problem with brown spots on my Gymno Spegazzini, any tips how to handle?
Thanks in advance.
Picts attached


Regards,
hendry

[Steve Johnson]

All,
Im having problem with brown spots on my Gymno Spegazzini, any tips how to handle?
Thanks in advance.
Picts attached


Regards,
hendry

Ooh, I think you have flat mites -- see this Wikipedia article for more info. I have some experience with this pest, and unfortunately you won't even know you have them until after the damage has been done. If you have access to a 10X magnifier, you'll be able to see them as teeny tiny oblong things (mine looked orange). Flat mites don't move around much, although you can see them crawling along as they find places to attach on the skin.

Unless you know for sure that you don't have flat mites, I would recommend mist-spraying with alcohol (isopropyl, methylated spirits, or whatever. Doesn't matter -- alcohol is alcohol). Flat mites don't reproduce as quickly as red spider mites, so spraying every 2 weeks is fine. Just make sure that you keep the plant away from direct sunlight when you spray. And keep at it until the infestation is over, then spray a few more times just to be extra sure. My only caution is that the waxy skin on some cactus species can be disfigured by alcohol sprays. I don't know if Gymno spegazzini is affected that way, so hopefully someone else on the forum can pick this up and let us know either way.

Sorry if you are in fact dealing with flat mites -- maybe too hot for them in your Summers, although I don't know enough about Indonesia's climate to tell you if there are certain times of year when your cacti are most vulnerable. Best of luck, and let us know how it's going.

[hendryterok]

Ooh, I think you have flat mites -- see this Wikipedia article for more info. I have some experience with this pest, and unfortunately you won't even know you have them until after the damage has been done. If you have access to a 10X magnifier, you'll be able to see them as teeny tiny oblong things (mine looked orange). Flat mites don't move around much, although you can see them crawling along as they find places to attach on the skin.

Unless you know for sure that you don't have flat mites, I would recommend mist-spraying with alcohol (isopropyl, methylated spirits, or whatever. Doesn't matter -- alcohol is alcohol). Flat mites don't reproduce as quickly as red spider mites, so spraying every 2 weeks is fine. Just make sure that you keep the plant away from direct sunlight when you spray. And keep at it until the infestation is over, then spray a few more times just to be extra sure. My only caution is that the waxy skin on some cactus species can be disfigured by alcohol sprays. I don't know if Gymno spegazzini is affected that way, so hopefully someone else on the forum can pick this up and let us know either way.

Sorry if you are in fact dealing with flat mites -- maybe too hot for them in your Summers, although I don't know enough about Indonesia's climate to tell you if there are certain times of year when your cacti are most vulnerable. Best of luck, and let us know how it's going.[/quote]

Thanks for your advice my friend...
Other question, should I mix alcohol with water and what percentage? Here we have alcohol 70% at stores
Regards,
Hendry

[Steve Johnson]

70% IPA is what we get here in the US, so I don't see any reason to dilute further than that. Also, make sure that you spray the affected plant thoroughly -- dry spots that get missed only invite the mites to keep going. If flat mites did attack your Gymno, you may want to give your other cacti close inspection on a regular basis. Knowing what mite damage looks like will go a long way to nip further infestations "in the bud" before the damage goes too far.

[hendryterok]

70% IPA is what we get here in the US, so I don't see any reason to dilute further than that. Also, make sure that you spray the affected plant thoroughly -- dry spots that get missed only invite the mites to keep going. If flat mites did attack your Gymno, you may want to give your other cacti close inspection on a regular basis. Knowing what mite damage looks like will go a long way to nip further infestations "in the bud" before the damage goes too far.

Thanks Steve, will do

Regards,
Hendry

[Cool Potter]

Thanks for this advice Steve. I have just discovered (with the help of a binocular lens) that I have red spider mired on my Pachypodium! I was worrying about metho attack on the plants well being and am glad to know that I can go ahead…..full steam!

[Steve Johnson]

This just in -- A. Dean Stock gave me a big "thumbs up" recommendation on TetraSan as a highly effective miticide/ovicide against spider mites, including flat mites. I just started using it, and I gave IPA the old heave-ho. There seems to be no phytotoxic reaction on cacti or succulents, so I'd say that it's perfectly safe on all plants. I don't know if TetraSan is available outside the US, but if so, it may be under a different trade name. Definitely worth looking into!