APHIDS (Greenfly)
Aphids are familiar to everyone with any plant-related interest. Many consider them more of an annoyance than anything else, but they can be a real threat. Like many pests, aphids excrete a waxy substance called honeydew. In and of itself, honeydew might be merely a cosmetic problem. The danger is that it attracts other insects, and encourages mould. The build-up of both mould and honeydew can inhibit photosynthesis, and cause other complications.
If your plants are outside or in a greenhouse, ladybugs may be your best solution. If indoors, insecticidal soaps and a systemic product should be tried before resorting to insecticidal spray.
BEETLES (stink bugs/squish bugs)
These distinctly odiferous pests suck the sap from plants, causing wilting. The adults are dark brown to black, and their orange eggs are found on the underside of leaves. The only recommended treatment I have come across is Malathion, which is a contact insecticide.
FUNGUS GNATS
These mosquito-like creatures are especially dangerous because they carry fungi such as Botrytis, Pythium, and Fusarium. Your first line of defence should be sticky traps, or the predatory Hypoaspsis mite if you have a greenhouse. Soil drenches such as Diazinon and Gnatrol are also effective, as are contact insecticides like Enstar (kinoprene) and Schulz (pyrethrins).
MEALY BUGS
The Ultimate Bane of Succulent Cultivation. Several different types of these nearly microscopic bugs prey on Cacti and succulents. Since they are virtually impossible to see with the naked eye, they are most readily identified by the presence of the cotton-like material they produce. They can be found almost anywhere on plants, and they, too, excrete honeydew. Thanks to some very timely (for me) discussions on e-mail lists, I have been able to put together many potential treatments. Most of these I have not tried personally, but they have been very effective for the growers who have recommended them.
The most common solution to a very mild infestation is hand-removal, usually with a cotton swab soaked in rubbing or grain alcohol. If the weather is co-operative, carefully hosing the plants down can also be effective. Several growers have said spraying with hot tap water can work as well, although this should not be tried on thin-leaved plants. Three other home remedies have been recommended: -10cc of common mineral oil and 3-4 drops of dish soap, added to about a litre of water. Spray plants well three times at five-day intervals. -Add about 10 cigarette filters to a 500ml bottle of methylated sprits. Let the mixture brew, shaking the bottle once a day. After a week, apply the mix with a paintbrush.
| Here's the follow-up discussion on this article: | View all related messages |
For a complete listing of article comments, questions, and other discussions related to Leigh SumnerKirk's Cacti & Succulents topic, please visit the Discussions page.