PESTS.
Orchids generally do not suffer from the usual plethora of ailments which affect many of our favorite garden plants, this is for two reasons, firstly many of the species and hybrids we grow are alien to our local atmosphere, and consequently also alien to many pests and diseases we find outdoors, and the second one is that because of the fact that we grow them mainly indoors they are not exposed to the problem in the first place.

Unfortunately, when a problem occurs it can be difficult to eradicate once is gains a foothold.

Here are a few, in no particular order:-

Slugs, even if you think you haven't got any problem with these night-time assassins, you should always be vigilant for their silvery trails, sprinkle at regular intervals with a good slug liquid, and if you feel adventurous, take a torch-light trip into the growing area after dark, a good well aimed boot is something they have not grown immune to.

Weevils, when you wonder why there is suddenly a hole in one of your best grown leaves, or chunks missing out of its margin, then most likely you have weevils, arm yourself with a bottle of something suitable from the garden centre and follow the instructions, its no use spraying the once, you must have strict regime of spraying every 5 days or so over a period of three weeks to eradicate most pests and their eggs as they hatch.

Scale, there are two types of scale which you are likely to encounter when growing orchids;-

The first one attacks Phaleanopsis in particular, and can migrate to most other soft leaved plants, look on the underside of the leaves for these hard brown limpet like creatures, if you have only one or two, wipe them off with a cloth soaked in methylated spirits, or resort to a systemic insecticide regime as mentioned in the above paragraph, systemic insecticides act by being absorbed into the plant tissue, effectively making the plant poisonous to its attacker, but they should be used with care, do not exceed the stated dosage to avoid damaging the plant.

The other can be very nasty, and primarily has a taste for Cattleya's and their cousins, this is Boisduval scale, a very fancy name for a real horror, you may notice flat round scales on the underside of the leaves, which if left unattended will produce a whole shipment of what appears at first to be a white fungus or mealybug, these are the nymphs by the thousand, and they are setting off to desiccate the rest of you collection, the problem we have in the UK is that it is a tropical insect, and many of our pesticides do not treat the problem, one we have found to be of use recently is Leavington's Natures Answer Insecticide and Fungicide combined, this does unfortunately cover the plant in what appears to be white dust, but it is very effective against this type of scale, and several other pests as well, you will probably have to give the plant a good cleaning after a couple of weeks or so for aesthetics.

Mealybug, usually appears as a cotton wool ball around leaf axils, or inside the sheaths of new shoots, the above fungicide.pesticide soon sees them off, but again if its very localized, then methylated spirits on a cotton bud sees them off wonderfully.

Thrips, greenfly, blackfly, spider mite, they all find a niche somewhere, the latter is another difficult customer to deal with, and in addition to spraying, it is a good idea to wipe the leaves and stems of infected plants with a meth soaked cloth, every few days if necessary to kill the eggs.

One home made cure can be produced in the kitchen if you want a non toxic insecticide, here is the recipe for you to try at your own risk :-

Six heaped teaspoons of ascorbic acid (vitamin C.) three teaspoon of plant friendly detergent (non ionic) and a pint of water, spray onto aphids and suchlike, the mixture will kill any insects which absorb oxygen through their skin, but not their eggs.

As prevention is always better than a cure, treat new plants with respect, quarantine them if possible, try not to let intake fans suck air in from anywhere near a flower border or hedge, and always be prepared to sacrifice a "well infected" plant for the sake of the rest.  Return to top of page

SPOTS AND DISEASES.
Orchids can fall foul of leaf rot, mildew, botrytis and many other pathogens, by and large, providing there is a good air movement around the plant, and that by nightfall the leaves are fairly dry, then fungal infections should not be a problem, and correction of the bad condition, along with a fungal spray (check with the garden centre that it is safe for orchids) should do the trick, a fast fix for a localized leaf infection is to dust a little cinnamon onto the infected area !

It is very difficult if you have a plant suffering from a virus disease to identify which particular type it is, and most likely a useless exercise anyway, as viruses are almost impossible to cure, thankfully, providing you are hygienic around the growing area, and that any tools used on the plants are thoroughly sterilized after use between different plants, you should not encounter this type of problem.