A seemingly simple vegetable to grow, spinach is sown directly in the garden during the cool periods of early spring or late summer-early fall. If planted sparingly or thinned well after planting, they offer generous yields as the plants can spread their leaves to their full potential, whereas if too thick they tend to turn a bit and stay small.
Spinach has high water requirements and cannot tolerate drought, especially when combined with heat, which causes them to be planted early. With a little care it is possible to produce bountiful harvests and with tunnels or fleeces the harvest season can be extended into autumn and earlier into spring.
Like other vegetables, spinach can also be affected by animal diseases and parasites, which you must learn to recognize and prevent. In organic farming, prevention mainly involves applying good rotation criteria, correct irrigation and moderate fertilization, then intervening, if necessary, with a few products with low environmental impact.
Now let’s see what are the main insects and pests that threaten spinach cultivation and how they can be treated in an environmentally friendly way.
Moscow South American Mining
land of night
slugs and snails
It is an insect of the order Diptera, which at the larval stage digs very fine tunnels (mines) in the parenchyma of spinach leaves. The insect has 3 generations per year and hibernates in the ground as a nymph a few centimeters deep. Therefore, in order to avoid major spinach maggot damage, it is important to practice crop rotation, so that the life cycle of the insect is interrupted, making its life more difficult. It should not be left to find the spinach in the same place the following spring, but it should always be moved.
During cultivation, it is recommended to treat with azadirachtin (neem oil) when the first mines appear on the foliage. It is obvious that it is important to keep the crop under surveillance in order to detect in time any attack by this leaf miner or other insects, because natural products such as azadirachtin have a less shock effect compared to the insecticides used in conventional farming.
South American mining fly
Also in this case, the insect is a dipteran, which makes numerous punctures in the leaves to feed on their tissues, leaving punctiform necrotic marks. The larvae of the South American leafminer, like those of the spinach fly, dig fine tunnels in the leaves and attacks are frequent, especially on late summer-autumn crops. Azadirachtin is also effective against this parasite, so the same precautions used against spinach maggot apply.
Some nematode species can damage spinach, for example the rather polyphagous Swiss chard nematode (Heterodera schactii). The problem is that this parasite is able to survive for years in the soil, and in the absence of host plants this is possible due to its transformation into cysts. The nematodes adhere to the root system (white cysts can be observed on the roots), leading to the vegetative decline of the plants. To avoid the presence and massive damage of nematodes, large rotations must be carried out and horseradish plants must be grown as bait to control their presence. Also, planting marigolds in the garden can help. Other species of polyphagous nematodes, which can also affect spinach, can be recognized by their attacks on the very wrinkled and misshapen appearance of the leaves and the general rotting of the plants.
Cutworms like Agrotis segetum and Agrotis ipsilon have 2 or 3 generations per year and cause very similar damage, killing plants. The larvae of these butterflies feed on the roots and remain in the soil. To be sure of their presence, walk around the spinach plants and see if they come out of the ground. Already in this way many of them can be removed manually, but for faster treatments you can try pyrethrum.
Spinach, as well as other vegetables, can also be compromised by voles which, with their root erosions, cause plants to wilt. You can’t do much against mice, but there are a few tricks to keep them away. For example, glass bottles can be buried in the ground halfway up and at an angle, so that the whistling of the wind disturbs them, as well as the underground vibrations produced by the periodic knocking of the metal poles planted in the ground which disturbs them. move away. There are also special tools that emit disturbing vibrations for mice, but in any case, the presence of cats is the most natural and effective solution.
Limits and snails
Slugs and snails are very happy to eat leafy vegetables and therefore also spinach. To counter the damage, some tricks should be applied, for example, setting up beer traps widely, which should be buried in the ground, spreading wood ash around the crop, and finally collecting the snails manually, even with l using bait such as boards or under overturned pots under which the snails can shelter during the day. There are also organic snails based on iron orthophosphate, to be sprayed in flowerbeds.
Bean aphid or green peach aphid can also affect spinach and, as in other crops, dense colonies of these small, sticky honeydew pests are noted.
Aphids are prevented by spraying fresh extracts of nettle, chilli and garlic, and eradicated by spraying the crop with an aqueous solution of natural Marseille soap at night. Afortunadamente, en la naturaleza los áfidos son presa de las mariquitas y otros insectos útiles menos conocidos, como las moscas volantes, los crisopas y las tijeras, por lo que es important evitar los insecticidas no selectivos y de efecto derribo para preservar la diversidad biológica en the environment.
Another form of prevention against aphids is balanced fertilization: a soil that is too rich in nitrogen causes the plant to absorb excess nitrogen and to have more spongy tissues that are more susceptible to aphid bites. Even with granulated manure, which is concentrated, care must be taken not to exceed the dosage.