Like in the case of any other plant, pests may also bother your bonsai trees. However, you can get rid of them successfully using biological means or beneficial insects, provided you are able to detect the pests early enough. Often many gardeners find it difficult to use natural predators, which are natural enemies of several pests. Nevertheless, when they have witnessed, and may be even benefited from this natural means of fighting pests, they are convinced regarding the effectiveness as well as the various benefits of this process. Precisely speaking, the fundamental principle of successfully eliminating harmful pests by using natural predators is related to the competition among organisms to survive. When you employ a pest's natural enemy, it will prevent the pest from multiplying, as most of them will be devoured by their natural predator. When there is an absence of the natural enemy of the pests, which usually occurs in the instance of small trees grown in containers, the pests will be encouraged to reproduce rapidly and eventually consume the plant itself. While you are using beneficial insects or natural predators to check as well as eliminate pests invading your bonsai trees, you will observe that these beneficial insects actually survive till their food or the harmful pests are available. Once their food is exhausted, the natural predators also disappear. In order to use the natural predators successfully to eliminate the pests, you need to ensure certain conditions - for instance, the temperature should be no less than 64�F (18�C). As the same time, you need to bear in mind that using natural or biological means to eliminate pests will not yield results as quickly as using chemical pesticides. Therefore, gardeners using this method need to be patient. In any case, people growing bonsai need to have patience. Now, let us take a look at the particular pests that usually invade bonsai trees and the natural ways to deal with them.
These pests are generally found either on the leaves' underside or in the region of a newly developing bud. Aphids actually suck out the life (life sap) from any plant they invade. Usually, aphids can be got rid of by giving your bonsai trees an excellent shower in the bathtub. However, if this does not yield the desired results, you may spray the bonsai tree with any garden spray like Metasystox, which contains an organic substance called pyrethrum. On the other hand, if you wish to employ natural predators to get rid of aphids, you can do so successfully by introducing lacewing larvae, which are also called "aphid lions". In addition, using yellow stickers (which are actually yellow colored cards with an adhesive surface) is effective in eliminating flying aphids. While the yellow color of the sticker draw the flying aphids to them, they eventually get stuck to the adhesive and die.
These pests are small and appear as brownish insects having a mound shape, very similar to pockmarks. Scales are usually found on the bottom side of leaves or the stems. Usually, you can scratch them off using a toothpick or even get rid of them using your fingernail. Alternately, you can put a cover of paint on as well as around these pests with a cotton swab drenched in methylated spirit. However, if all these measures fail to provide the desired results, you should spray the bonsai tree with any good quality garden spray that contains either dormant oils or a blend of kerosene and borax.
If you notice a fine web stretching across yellow leaves of your bonsai, you should be certain that the plant has been invaded by spider mites. In case you can detect the mite, you need to shake a branch of the bonsai gently over a white sheet of paper. When the mite drops on the paper you will find that it appears similar to a red powder, something like paprika. However, occasionally, they also have a yellowish or brown color. These mites are so minute that you can only see them under a microscope or magnifying glass. To eliminate these pests from your bonsai quickly, it is advisable that you use Pentac (dienochlor), which is an acaricide, or Metasystox-R (oxydemeton-methyl). On the other hand, in case you have detected the spider mites quite early or if you desire to undertake a follow-up treatment using a preventive, it is suggested that you employ predatory mites - the main natural foe of spider mites.
Springtails usually survive in or on the surface of the soil. These pests usually toss around in a jumpy manner. In fact, when an individual pest is present on the plant it is considered to be somewhat beneficial. However, when these pests invade your plant in large numbers, they turn out to be a major nuisance, as they start attacking the roots of the bonsai. It is important to note that springtails can only multiply when the soil is damp. Therefore, it is advisable that you use a household spray on your bonsai to get rid of these pests.
These pests are generally found on hibiscus, pomegranate and Sageretia. Whiteflies thrive as well as flourish when the environment is arid and the air is stale. The eggs and larvae of whiteflies are generally concealed on the lower surface of the leaves. When these pests invade your plant, sometimes the leaves' surface develops a yellowish sprinkling. However, the good thing is that whiteflies can be combated by employing their natural predators - the ichneumon wasp. Alternatively, you can also spray the affected bonsai with any garden spray containing either an oil blend or any contact insecticide, both of which are very effective. Similarly, you can also eliminate these pests using organic preparations containing pyrethrum or using the yellow sticker cards.
Mealy bugs have a rather uncommon appearance. These pests look similar to cotton balls resting on twigs, axil of branches and leaves. It is a very small insect that conceals itself in the middle of the cotton ball and a wax-like covering which protects the insect from its predators. In order to eliminate this bug, you need to treat your bonsai using a pyrethrum spray or any other contact insecticide. Interestingly enough, mealy bugs do not have any natural predator or enemy.
This pest is different from the mealy bug discussed above and, as the name suggests, it invades the roots of a plant and, if not checked, kills the plant. When the root mealy bug invades a plant, it may result in the leaves turning yellow and subsequently killing the bonsai. The best way to find out if your bonsai has been affected by root mealy bugs is to take the plant out of its container; examine the roots of the plant and see if there are any white-grey clumps resembling cotton balls on them. If you find their presence, you can be sure that the bonsai has been affected by this pest. There are a number of ways to combat root mealy bugs. Diazinon can be used to get rid of common infestation. On the other hand, watering the soil with a solution containing Metasystox is effective in cases of severe infestations.
There are several different types of caterpillars and all of them have an insatiable hunger for foliage. These caterpillars attack the bonsai leaves so ruthlessly that they virtually destroy the plant. A number of these caterpillars develop inside cocoons on the bottom surface of the leaves prior to appearing during the daytime. They usually curl themselves into silky webs and, hence, they have been named tortrix caterpillars. Occasionally, these caterpillars also develop inside the leaves as well as the flower buds of the bonsai. It is worth mentioning here that it is always not easy to get rid of caterpillars. This is mainly because at times caterpillars become resistant to insecticides. Therefore, whenever you notice one, you should remove it by hand and destroy it immediately. On the other hand, applying a good insecticide that remains on the leaves for a longer period may also yield good results, because the caterpillar will consume the insecticide as it continues eating through the leaves. Alternatively, you may place a saucer with glue at the bonsai's base, as it may help in catching some caterpillar species that may drop from the affected tree. The glue will stop these caterpillars from climbing back onto the bonsai at night during autumn, thereby preventing them from laying their eggs on the plant's leaves.
There are a number of insects that my lay their eggs in the compost of the bonsai - precisely speaking, in the plant's root ball. Once hatched, the larvae of these insects particularly have a fondness for young roots, which they consume rapidly, thereby depriving the plant of its necessary nutriments. Therefore, it is essential to remain alert when you are repotting the plant. If you detect the presence of any larvae during this time, you can eliminate them with your finger nails. In addition, it is advisable that you also use an appropriate insecticide, such as hexachlorocyclohexane (HCH).
In a number of ways, ants are considered to be rather alarming pests. As ants are fond of aphids, feeding on the excretions on the aphids, ants virtually "farm" these pests. Precisely speaking, ants transport aphids from one plant to another, thereby protecting them from their natural predators like ladybirds. As ants want to be closer to their food source, they have a tendency to gather together in nests dug out in the soil in the region of the roots, thereby destroying the root system as well as bore the roots while they create tunnels to facilitate their movement through the root system. Therefore, the only remedy is to place a trap for ants on the root ball's surface. In case, ants have established a nest in the root ball, the only way of protecting your bonsai is to lift it from its container or tray. Subsequently, discard the soil and get rid of the maximum number of larvae possible. Ants are easily dislodged from their nest when there is any kind of disturbance. Generally speaking, when you are combating pests that have attacked your bonsai tree, you should always remember that there is life where ever there is soil. At the same time, you need to bear in mind that everything that moves is not harmful or perilous. In due course, you will be able to develop a sharp eye and also know how to distinguish between what is hazardous and what is not. In fact, there are some species that respond very badly to specific pesticides. Therefore, if it is possible, you should visit a nursery to know about these prior to using any of them. While deciding on the use of any specific preparation, you should not discontinue with the treatment very soon, despite the fact that you may believe that you have emerged victorious in your fight against pests invading your plants. Go on with the treatment at least twice or thrice more. When you have done this, you can be certain that even the eggs left behind by some pests have also been destroyed. At the same time, you need to ensure to store all the pesticides as well as other chemicals in a place that is beyond the reach of children and pets. They should be kept in containers with clear markings or labels. Before using the preparations, it is important to read the instructions thoroughly and ask all people to leave the area and also remove the pets before applying the chemicals. Always spray the plants in an area that is properly ventilated. Last, but not the least important, don't forget to use appropriate protection for yourself like using a face mask and gloves.