Garden Pests

[tamsin]

My lovely frangipani tree is covered in little white cotton wool type creatures (never see them move), who distort the leaves, making them curl up. I spray them with a very potent (so I'm told - it certainly smells very bad) insecticide, but they're back again after only a couple of days. What are they?

[Jamie]

Do you have a picture you can post?

[sbk]

From the description it sounds exactly like Woolly aphids:

The usual symptom of their presence is distorted, weak growth of leaves and shoots. A large infestation can cause roots to reduce in size due to the sucking activity of the aphids increasing the transpiration stream, so the plant requires fewer roots to supply the volume of water by normal means.

They can be carried long distances by wind currents, and can transfer viruses as they move to other plants. The honeydew they shed sticks to leaves and can be colonised by Sooty Mould. One species infests most Lime trees - the honeydew covers parked cars and plants below them. Some colonies of Ants 'herd' the aphids and collect the honeydew to feed their larvae; they protect the aphids and carry them to overwinter in their nests.

In spring and summer only females are present reproducing asexually, giving birth to live young. In the autumn, males are produced and after mating the females lay eggs which remain through the winter in crevices. The population can double in 4 - 6 days; starting with one aphid, after one year of uninterrupted reproduction in perfect conditions would produce 250 million tons if none died! This means that they are a good source of food to other creatures including Ladybirds and their larvae, lacewings, hoverfly larvae and parasitic wasps.

Where only a few are present they can be rubbed off affected shoots, after a while natural predators will arrive and remove them. A hose with good force can be used to dislodge them from tough-leaved vegetables. Placing aluminium foil or a mirror below plants, fools them into flying upward.

A spray prepared from a couple drops of washing-up liquid to a gallon of water as an acceptable organic method of control; so are insecticidal soaps made from plant fatty acids. Avoid spraying in sunshine to prevent scorching the plant.

Biological controls need a constant supply to survive, so there will always be a low-level presence, hopefully these will be on nearby wild plants. Ladybirds are nocturnal so if they are feeding during the day the number of aphids may be low.

For chemical control use pyrethrins or bifenthrin - spray as late in the day as possible to avoid Ladybirds and other friendly creatures. An acceptable organic spray is made from an extract of the Neem tree called Azadiractin

Bane of my existence. My pumpkin bamboo is infested with these buggers. I'm afraid to prune because the wind will spread them throughout my garden

Is Neem extract readily available in Thailand? Anyone know a product name to look for?

[Jamie]

You could try making something yourself. Try a non-detergent liquid soap 10-25 ml per 4 liters of water. Also, process hot peppers, onions and garlic. Process until liquified, strain the liquid in to a bottle along with a little soap (1-2 ml) and add to 4 liters of water.

[sbk]

soap never worked for me.

And my bamboo is absolutely covered, I've never seen anything like it. The bamboo doesn't seem to be suffering for it, but a bit of a spray wouldn't do much to this infestation.

[loong]

Soap has rarely worked for me either. Are there different strains that are immune.

I've had some success by spraying a weak solution of coffee (no milk or sugar ). But need to spray daily for a week. Again, though, this doesn't work every time.

[Jamie]

If you have such a bad infestation, sometimes the only way to get the problem under control is physical removal. Usually with a blast of water. Either that or find someone you can get a steady supply of lady beetles from. I use a product called "Safer" insecticidal soap and it has worked well on any aphid problems I have had. I've never had problems with big infestations though.

Neem oil should be readily available in Thailand as the Neem tree is native to India and Burma (Azadirachta indica). Azadirachta siamensis grows native in Thailand.

[pete_r]

In Bangkok I've seen neem extract for sale in Homepros (pesticides and fertilizers section). The name was written in Thai and I recognized only the word "sadao" (neem), but the picture was telling. Jatujak would be a good place to look as well.

[Sheryl]

Bane of my existence. My pumpkin bamboo is infested with these buggers. I'm afraid to prune because the wind will spread them throughout my garden

Is Neem extract readily available in Thailand? Anyone know a product name to look for?

Yes. It's sold in Home pro and other places. Large bottle with the number "111" on it.

[dkstoney]

You guys should listen to Jamie on this one. Nevermind the soap, but the peppers, garlic, and lime juice (my addition) will rid them with daily spraying.

[cmsally]

I had a fair amount of success with chillis and a bit of veg oil mixed in with the water.

Also spray hose water on the tree regularly to dislodge them.