The green caterpillar is one of the most common pests, widespread and feared by every grower, because it is present in any type of cultivation. It is a pest typical of traditional crops and – to a much lesser extent – of indoor crops. It is usually green in colour, but it is not uncommon to find different colours, such as dark grey, brown and orange. So let’s see how to deal with it, how to prevent it and how to eliminate the families of green and not green caterpillars that attack our plants.

How common is it and when does it spread?

The green caterpillar is very common in spring and summer and can be found mainly among the plants of outdoor crops, in traditional outdoor gardens (read also the article about the hydroponic garden in the house) , such as decorative plant bushes, and in vegetable gardens. They are much less common in indoor cultivations, those inside grow boxes and grow rooms, where the environment is generally more circumscribed, but above all controlled and clean just to avoid the arrival of parasites and dangerous external elements. In particular, green worms attack plants with very green leaves, such as basil, salad and rocket, tomato leaves, chilli and cabbage, but – in reality – these pests often attack rose plants and geraniums. It is no coincidence that, given the spread of these types of plants, they are also commonly called basil caterpillars or rose caterpillars.

Where are the green caterpillars?

Some families of these caterpillars feed on the leaves of the plants, other species prefer instead of the inner part, in the pith, and attack the stem of the plant, in correspondence of the softer and even more easily attackable parts. As a general rule, the green caterpillars tend to eat mainly at night, whilst during the day they prepare their den by digging deep holes close to the plants which they then attack.

What do caterpillars look like?

Green caterpillars represent the initial stage of lepidoptera and butterflies. Their body is generally thin (but some have a thicker diameter) and are usually long and soft in texture. Their body is divided into three distinct parts, even at first glance: head, chest and abdomen. The particularity of caterpillars is their ability to camouflage themselves thanks to the colour of their body; in fact, they have the same colouring as the leaves, an aspect that makes them very difficult to spot and, therefore, to fight.

Each family of caterpillars has different sizes and colours and therefore the types of leaves and plants attacked will also be different.


The adults of the agrotites are lepidopterans of grey or dark brown colour, have a wingspan of a few millimetres, are about 2-3 mm long and the colour is usually green, the most common shade, but can also be pink, grey and black.


The adult specimens of the cabbages are dark coloured lepidopterans and have a wingspan of a few centimetres. The caterpillars of the family of the newborn cabbages are usually green, slightly mottled and can grow up to a length of 4 centrimeters, when they become well visible on the plants.


You can find different families of phytophagous that transform and become adult lepidoptera, which take on different colours and sizes. Also in this case, caterpillars are generally green in colour, but they can also have different shades, especially if they are grey or brown and their body can be up to four centimetres long.

What does the caterpillar do to the plant?

As mentioned above, caterpillars attack the soft leaves and stems and feed on the softer part inside. The branches and leaves attacked by the caterpillar wither because they do not receive water and nutrients properly. If these caterpillars also attack the main stalk, the whole plant will begin a process of progressive deterioration that will lead to the death of the plant. If the green worm infests only one branch, it will die – instead – only that branch.

Remember that plants are also susceptible to infections and mould as a result.

Prevention against green caterpillars: what to do?

How to prevent the arrival and aggression of caterpillars on plants? Surely, as mentioned above, starting a cultivation indoors – i.e. an indoor crop – almost completely eliminates the risk of caterpillars. If – on the contrary – you have decided to start a cultivation outside, the classic outdoor cultivation, keep the seedbed and the germination mini greenhouses as much as possible inside before transplanting abroad; this is to prevent caterpillars from attacking and destroying the plants at a time when they are still very young and weak. In order to avoid the infestation of green caterpillars – and other pests – it is important to constantly monitor the growing area and clean it from wild grasses and plant residues before planting the plants. Pure Cinnamon extract is an excellent product to prevent caterpillar infestation, regardless of the species it belongs to: cabbage, agrotites and phytophages will be eliminated with the same types of products.

How to eliminate green and other coloured caterpillars?

Various methods can be used to permanently eliminate a caterpillar infestation. If you only have a few plants, the easiest and most immediate way to control and eliminate caterpillars is to physically destroy them. If, on the other hand, the infestation is more extensive and you have already detected damage to the plants (in this case the caterpillars will be at a maximum distance of 25 centimetres from the damaged plant). The most effective method in such cases is undoubtedly to use an organic product containing a living bacterium: Bacillus Thuringiensis. These bacteria debilitate caterpillars – and also other animals harmful to plants – but are harmless to humans and pets. When caterpillars ingest the bacteria, they stop feeding – often paralyzed – and die within a short time. When they die, however, the caterpillars release new generations of bacteria ready to attack other caterpillars. Remember that it is important to use the bacteria at the first sign of caterpillars.

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