Surely, if aphids were causing a big problem you would have seen the little things by now.

I will tell you that horticultural oil applications can cause problems with plants if applied during very low or very high temperatures. That warning will be on the label of the product you are using.

Impatiens can have problems with various bacterial and fungal disorders. Did the lab check for anything like that, or just the virus? Some of these diseases can imitate INSV.

Hi Sherry,
they made it in good shape. we received the virus test kit this morning.

we just completed the testing now. all samples tested negative for CMV, TMV, INSV, and TSWV (these come standard in the 4-virus strip test that we purchase; i decided to use this strip test, which costs a little more but is more complete than a single ELISA; all five samples were tested individually; and don't worry - i have waived the extra fee associated with this strip test). the roots (where present) looked really healthy. this leaves either insect injury (very possible) or environmental/nutritional problems. it does not appear to be a disease.

i noticed the malformed new growth on the african orchid impatiens. i wonder if this could be caused by thrips feeding injury? thrips can cause malformed buds and new growth. i didn't see the typical black spots (bug excrement) that i typically see with thrips though, which caused me a little confusion. ....

i did find a single thrips on one of the samples. you don't want thrips levels to get out of hand - they can cause serious damage. here is some info on thrips from our extension entomologist:
"For insecticides, it is good to rotate chemicals and classes of insecticides
to avoid insecticide resistance in greenhouse thrips. Trapping is helpful to
indicate pest population levels with blue or pink sticky traps. There are
several biological control agents that can help keep the thrips population in
check and are commercially available. See website.

Am sending the letter I got from the lab so you can see what they tested for.
When you say that horticultural oil can cause problems with plants, do you mean temporary problems or chronic problems that will always be there?