Bonsai trees are living organisms like any other plant, and they are susceptible to all pests and diseases. However, the chance of infection is minimal when your plants are healthy and well-cared for.

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How to Identify Bonsai pests and diseases

The following may be summed up as proper bonsai care: Make sure your trees are planted in the appropriate soil mix, that you know how and when to water them, that you don’t over- or under-fertilize them, and that your bonsai is situated correctly. Healthy trees have a minimal risk of infection, although obviously, this does not mean that they cannot.

You may wish to take images and post them to our Bonsai forum to get assistance since it can be challenging to pinpoint the issue accurately. Some of the most typical issues individuals have with their bonsai plants are these:

Leaf decay on a bonsai

Suddenly turning yellow, the tree’s leaves start to fall. This often happens when there is a sudden shortage of water. The most frequent cause of the leaves progressively becoming yellow and dying is continuous overwatering, overfeeding, or underfeeding.

Discolored leaves and short branch dieback are signs of viruses and fungi viruses. To avoid cross-contamination, place the sick tree far from the other trees in your yard. Remove diseased tree portions, and then spray with a fungicide to treat.

Bugs are often spotted on bonsai

Compare the insects you see to the pictures below to try to identify them, or you may take a picture of them and upload it to a bonsai forum for help. Purchase a pesticide (chemical or organic) to treat the trees after the insect has been discovered. Start with a half dosage and be careful to follow the label’s instructions; if more is required, increase the dosages later.

Caterpillars

When a butterfly or moth is int the larval stage, it is referred to as a caterpillar. It is the second stage of their life cycle, which consists of four stages in total: egg, larva, pupa, and adult. Because the larger phases of a caterpillar’s development are typically when it is easiest to spot the differences in appearance between stages, we have focused on describing these stages. Some of them are simple to find on the plants that are their preferred source of nutrition.

Ants

Ants are beneficial to the ecosystem, despite the fact that they can be a nuisance when they invade your bonsai garden or when you’re trying to enjoy a picnic outdoors. Because they are sociable insects, they congregate in big colonies or groups rather than living alone. Ant colonies can have up to millions of members, depending on the species that inhabits them.

Within an ant colony, there are three different kinds of ants: the queen, the female workers, and the males. Wings are only present on the males and the queen of the colony; the workers are wingless. The only worker ant that is able to produce offspring is the queen. It is the task of the male ant to marry with the female ant that will become the queen, and male ants do not live very long after mating. When the queen reaches adulthood, the only thing she does for the remainder of her life is lay eggs. There may be only one queen in a colony, or there may be several queens, depending on the species.

Soldier ants are a common component of ant colonies. These ants are tasked with guarding the queen, defending the colony, gathering or killing food, and attacking neighboring ant colonies in pursuit of food and nesting space. If they are successful in defeating another ant colony, they will collect the eggs from the colony that they have just vanquished. As soon as the young ants emerge from their eggs, their role in the colony is to serve as “slaves.” Gathering food for the colony, tending to the eggs and young, and constructing the anthills or mounds are all tasks that fall under the purview of the colony as a whole.

Aphids

Aphids are insects that are quite common and can be found on almost any plant that is grown in yards and gardens. In the majority of circumstances, they have a negligible or even beneficial effect on the health of plants. Leaves that have been crinkled and twisted, leaves that have turned yellow, stunted or dead shoots and overall poor plant growth are all indicators of severe aphid feeding. In most cases, it is not required to treat plants for aphids in order to protect the plants’ health. The management of aphids typically requires simply the application of non-chemical or low-risk pesticides.

Spider Mites

These itty-bitty parasites that feed by sucking can swiftly cause havoc in both indoor and outdoor gardening. This is the all-natural and organic approach to getting rid of spider mites as quickly as possible.

Spider mites, is an insect that belongs to the family Tetranychidae and are quite abundant in North America, can be a problem for both indoor and outdoor plant life. They can be particularly damaging in enclosed spaces like greenhouses.

Spider mites are not insects in the traditional sense; rather, they belong to the arachnid order and are related to other insects like spiders, ticks, and scorpions. Adults are reddish brown or whitish in color, oval in shape, and very little (approximately 1/50 inch long). For comparison, the period at the end of this phrase is approximately the size of an adult. The juvenile phases are similar to the adult forms, although they are much smaller.

Mealybugs

The presence of these pests, which feed on the sap of plants, is a common issue in greenhouses, gardens, and on indoor plants. The following are some natural methods that can be used to control mealybugs, such as using insecticidal soaps, helpful insects, and other methods.

Mealybugs have no wings and have bodies that are soft. They thrive in warmer growing regions. They frequently appear as white cottony masses on the leaves, stems, and fruit of plants. Mealybugs feed on plant sap. They obtain their nutrition by inserting mouthparts known as stylets, which are lengthy sucking mouthparts, into the tissue of plants and sucking off the sap. When there are low numbers of pests, the damage that they cause is usually not considered. At higher concentrations, though, they can cause the plant’s leaves to yellow and curl as well as weaken the plant overall. Honeydew, which causes the plant to become sticky and fosters the growth of sooty molds, is typically produced while a plant is being fed. Mealybugs are frequent insects that can be found in greenhouses. They feed on ornamentals, houseplants, avocados, and fruits.

Vine weevil

Currently, there are more than 500 known different spicies of weevils in the United Kingdom. Weevils are comprised of numerous families of beetles that belong to the superfamily Curculionoidea. All of them consume plant matter, more often than not living plants, but some, like grain weevils, also consume dried seeds and rotting wood. The majority of them do not cause any obvious damage to the garden plants, and quite a few of the species are quite rare.

The vine weevil feeds on a wide variety of plants, whether they are cultivated indoors or outdoors, but they are particularly destructive to plants that are kept in containers. It is an insect that is found all across the world and is highly prevalent. The adults of the weevil feed on plant leaves in the spring and summer, but it is the grubs that are responsible for the majority of the damage since they feed on plant roots in the fall and winter. This damage can lead to wilting and ultimately the death of the plant.

Vine weevil grubs are most likely to cause significant harm to plants that are growing in pots and containers, whether they are growing outdoors or under cover. There is a lower risk of damage to plants that are growing in open ground; but, severe infestations of grubs can occur on strawberries, Primula, polyanthus, Sedum, Heuchera, and young yew plants.

Scale Insects

Scale insects are a huge and diverse group (approximately 8,000 documented species), belonging to the superfamily Coccoidea of the order Hemiptera. Although they are closely related to aphids and whiteflies, they do not resemble the conventional appearance of insects in any way (the mealybugs are part of this superfamily, too, but are not included in this article). The common name for these tiny insects comes from the fact that their sizes and appearances might vary greatly (ranging from 1/16 to 3/8 inch across), but they all develop behind a wax covering that mimics an individual reptile or fish scale. This protective covering might take the form of an elongated oval, a dome, an oyster shell, microscopic mussels, or be covered with a fluffy substance. Its function is to shield the insect that lives underneath.

Female scales are typically unable to move, have no wings, and frequently do not have any legs or antennae that are visible; they do not even resemble animals. The male scale is rarely seen and resembles a gnat in appearance; however, it does not have mouthparts and hence cannot feed. Some species reproduce only through the process of parthenogenesis, whereas others are hemaphrodites. Eggs are laid by females beneath their bodies, and as they hatch, the resulting creatures are known as crawlers because they move around on their legs and are the initial stage of development.