Beginners Corner - Pests

by Dorothy Franz

The biggest danger with pests is that they go undetected until there is a major infestation. Pests should receive as much attention as watering or any other bonsai consideration. Those of you that hand water have an opportunity everyday to inspect your trees while you water and one should make a conscious effort to do so.

With automatic sprinkler systems the dannger of not spotting trouble becomes greater. While you may walk around your bonsai-en checking the watering etc. one is not seriously looking for bugs. Perhaps it would be a good idea to do a pest check every few days.

To minimize the breeding of pests and spreading of fungi, keep your bonsai area clean. Remove decaying leaves and debris, which create a breeding ground. I personally feel that doing one's major watering in the morning rather than the evening helps to reduce pests. Pests thrive in damp dark conditions.

Once you have detected a pest or fungi on a plant remove that plant from the area, isolate it and check that the plants around it have not been infected. To identify the problem either arm yourself with a good insect identification book or take a leaf or plant with you to a nurseryman who will be able to tell you what is affecting it.

There are two types of insecticides, contact agents and systemic. Contact agents will wash off during watering. Systemics are absorbed by the plant and therefore will last about ten days. Before mixing the insecticide read the labels carefully. Do not spray in a windy area and wear protective clothing, well, at least gloves and a mask.

Bacteria, fungus or insects and mites may attack your plant. Bacteria such as crown gall is rarely seen on bonsai and one is unlikely to get it on one's tree.

Fungi are sometimes difficult to diagnose and they usually form spots on the leaves with a lighter halo around it. Benlate and Funginex are two good fungicides. Care needs to be taken on trees that are dependent on mycorrhiza since some fungicides such as Benlate are known to kill it. Serious fungi cause whole branches to die back such as the root rot fungus we experienced on olives some time ago. This requires stronger solutions e.g. Aliette and Ridomil.

Insects like woolly aphids, red spider, scale, mealy bug, thrips, beetles and caterpillars can be treated with various sprays. Beetles and caterpillars require a systemic poison such as Folithion. For thrips use either Malathion or Chlorpirifos. For all the others there are various products on the market. Many do the same thing so before you go out to buy check your labels and be careful - it is poison.

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Distant mountain heights...

Lonely trees clinging...

In the hollow of my hand

Random Bonsai Tip

If a tree lacks a branch in a specific place you could in arch or approach graft a branch in the required area or thread graft through the trunk using a long shoot of the same plant.