The War Against Scale (Week 2)
 

This weekend marked my 2nd malathion attack against the scales attempting to invade my orchid collection. I'm currently planning a 3rd assault this following weekend, followed by enhanced vigilance. :)

Thank you, Ray and others, for your advice following my initial dosing. Ray, the addition of a little dish soap did, indeed, keep things in suspension nicely.

As you might guess from my various questions, I'm kind of a noob to using pesticides on my plants. As a biologist (with a chem minor) I'm not a noob to handling noxious chemicals or pathogenic organisms, however, so am good about all the necessary gloves / ventilation / disposal stuff. It's more the application / interactions with the orchids themselves I'm not always sure about.

So this week's questions are:

1) I've been doing the malathion as a bucket dip because I don't have anywhere I feel safe spraying during the winter. When using it as a dip, do I just dunk in and take out? Or should I leave the plant in the dip for a few minutes? So far, I've just done the dunk, and it seems to have worked fine (no sign of bugs at all during this last treatment).

2) Before dunking, I've been giving each of the orchids a soak in clean water to let all the roots turn green. My theory is that they don't need to be absorbing malathion, so saturating the roots before dipping will minimize unnecessary chemical absorption. Does that make sense?

3) Fertilizing. While doing the malathion treatments, I haven't been fertilizing. I figure the plants can handle three weeks without fertilizer, and I wasn't sure if the malathion and fertilizers played nice together. Is that an unnecessary worry? In general, do people mix fertilizers and malathion in the same water? In other words, could I be dipping for pests and fertilizing at the same time?

Thanks again, everybody! Orchidboard is the best. :waving

L.P.

Much as I hate spraying pesticides, I would never do a multi-plant, orchid dip/dunk due to possible cross contamination of virus, which has become rampant in today's pot plant market.

Cym Ladye

Have you tried isopropyl alcohol for scale?

kill the scale as rapidly as possible by whatever means necessary....use a systemic....also, to spray, get a large plastic bag, put the plant inside, and spray away.....gl

I've used shower stalls and baths to do indoors spraying before - shower stalls are quite nice as they're fairly easy to "decontaminate" afterwards and hold the spray well. I also live in an apartment and lack suitable spraying spaces.

I'd also be wary of multi-plant dipping.

I often use surgical spirits and cotton ear buds (q-tips) on minor outbreaks - wipe them off and have a good scrub at any little scale patches. Getting into the leaf axils is quite hard, notably on tolumnias. I've taken to pouring a little bit of a pyrethroid-based insecticide into there to take any out.

I also have a round of scale (and spider mite) dosing to do after being away for a month!

Thanks for the responses, everyone!

Yes, I use isopropyl for any individual scale I see. I resorted to chemicals after a couple weeks of intensive cleaning with alcohol and Q-tips wasn't getting on top of the problem. (As Discus mentioned, getting scale out of the leaf axils on tolumnia -- which is all I grow -- is near impossible!)

Thanks for the spraying suggestions, too. The one question which still stands: Is it OK to mix malathion with fertilizer, to do stuff all at once? Or should I hold off fertilizing on days when I "poison"? (This weekend should be the last chemical treatment, knock on wood.)

Thanks again!

I do not know of any reason not to combine your malathion dip with a dilute fertilizer solution. However, I would fertilize first before using Malathion as a spray just because fertilizer is better absorbed as a flush through the plant media rather than a foliar application.

CL