Aphids

      Aphids are in the zoological Order of Homoptera (pronounced "ho-MOP-ter-ah"), meaning "same wing" & are small (1/8" or 3mm long), soft-bodied, sap sucking insects that produce honeydew, a sugary protein substance that is in turn fed upon by other organisms, mainly ants. Adults can be either winged or wingless, & their colours range is mainly pale green, yellow, pink, & black. The woolly aphid is white & cover itself in a fine white fluffy down.
    There are more than 4,000 species of aphids (so what chance do our poor orchids really have) with 10% of the species attacking many species of plants, while others feed on specific plants. Some aphids do little damage, while others have a saliva toxic to plants or they spread viruses & diseases between plants.
As a group, aphids attack a plant by sucking fluids from tender new growths, they are attracted to this new growth by the high nitrogen concentrations in the growth tips. The sap sucking may result in wilting, deformed & stunted growth, yellowing, & even loss of leaves.
Aphids are divided into two major groups - the chief difference being those that only lay eggs (like the Pine Aphid) and those that have the ability to bear live young, the little suckers that attack your valuable plants fall into this second category.
     As the weather cools, the female lays an autumn batch of eggs in crooks and crannies throughout the landscape, but near host plants. They particularly like cracks in stems and under loose bark. In the spring, the eggs hatch and become "stem mothers" - that is, they are all female. They also already have their young within their bodies. These stem mothers produce more females, between 60 & 100 per week, which produce even more females - all without mating so within a few days, thousands of aphids can be born.
(this is the stuff HORROR Movies are made of!!)
    In late summer and early autumn, the females finally begin producing a few males. Females born at the same time have eggs within their bodies, they mate, and the eggs are laid to provide next season's offspring.
Besides deforming new growth, aphids cause additional problems. They eat more plant fluids than they can digest, & thus excrete a substance called "honeydew" - a sweet, syrup-like material which appears on leaves and stems.
   Honeydew on plant leaves can creates two more problems: Sooty mould and ants.
Sooty mould is a fungus that grows in the honeydew, & it makes the leaves look dirty and black. The honeydew is also sweet & a food source for ants. Ants will fiercely defend their honeydew "source" against all natural predators, like Lady Bird (beetles) & their larvae. They have even been known to move aphids from one plant to another so that additional honeydew "factories" can be created.
   Knowing all of this gives you the opportunity to control those pesky little critters in a variety of ways. The following are just a few ways to deal with them & is by no means an exhaustive list.
Strong water sprays -Tests have shown that by using the proper equipment, water sprays can be up to 98 %
effective in killing aphids. But watch water damage to plants.
Ladybird beetles (lady bugs) - The most common species is Hippodamia convergens (Convergent Lady Beetle), the "lady bug" of story book lore with red-orange wing covers and black dots. Both the adult and the larvae eat aphids.
Pyrethrin (with or without piperonyl butoxide) - This is a 1% extract from pyrethrum powder, a natural insecticide derived from a beautiful plant called Painted Daisy (Chrysanthemum pyrethrum). Piperonyl butoxide (or "PBO") is derived from sesame seeds and acts as a synergist (that is, makes these ingredients combined a lot more effective than their effects individually). Both substances attack the nervous system of the insect.
Horticultural oil - Such as “All Seasons Oil” which acts by smothering the pest insect’s breathing pores. On some insects it also acts like insecticidal soap - dissolving the cuticle.
Garlic-water sprays - Purchased or homemade concentrations act both topically and systemically. The active chemical compound ingredients work like pyrethrins, but also act as repellents to some pest species
Orthene Or Shield- These are but two of many insecticide sprays available. These are a systemic type weapon, that is they are absorbed into the sap stem of the plants, so anything that chews or sucks gets a dose of the poison.
Insecticidal soap - This insecticide dissolves the cuticle (the outer
covering) of the aphid. I’m not a fan of this one, finding cakes of soap small enough is one thing, but putting out the tiny towels & face cloths is a real hassle---Ed.