Pests and diseases

 In market gardening, any serious discussion of phytoprotection should recognize that the use of chemicals intended to destroy organisms (animals, plants, fungi) harmful to crops is a disaster for ecology and human health. The use of these products continue to be promoted despite overwhelming evidence of their harmfulness, which proves although we cannot rely on industrial agriculture for our food. It's a fundamental subject, but I prefer to leave it to others to discuss it. We know that in organic farming, these products are not acceptable, while some "biopesticides" are. But are these really ecological?

It is also common to hear or read than a biological (versus chemical) approach to agriculture reduces infestations parasitic; that attention to biology, to the physical structure and mineral balance of a soil helps grow healthy vegetables that are naturally resistant to disease and pests. Should we conclude that the presence of harmful insects and diseases is the result of bad practices in his market garden?

I have no certainty on these big questions. On the other hand, I know that certain pests and plant diseases occur. every season in our garden and that, if no preventive action is taken, these problems cause significant damage. Growing zucchini, for example, has no chance of living in striped cucumber leaf beetle if it is not protected. Moreover, it is wrong to imagine that customers will accept pitted radishes or tomatoes surrounded by black under the pretext that they are "organic". The success in your garden therefore implies good management of insects and diseases.

Several books dealing with biological solutions to insect problems describe the benefits of biodiversity. The presence of different plants, insects, birds and same amphibians on the same site reduced indeed the impact of pests on crops. The best way to achieve such biodiversity is to provide suitable habitat for living species that we want to welcome. Thus, the development of a windbreak or pond can include shrubs and other plants popular with insectivorous birds.
The arrangement of floral spaces inside and garden borders can be designed to attract predatory insects. Stone walls, bos quets and other small shelters can benefit many insects beneficial to crops. This kind of ideas deserve to be studied when design a market garden.

In our firm, we have made a lot of efforts in this direction; we have beehives to bring more pollinators and a water garden that home to frogs, insects and birds of all kinds. This body of water and the presence of a wooded area at the edge of our gardens benefit the toads who patrol our gardens at night to eat gray worms. We have built several nesting boxes that attract bluebirds and troglodytes, two insectivorous birds that hunt on the ground.

Since we settled on an ancient meadow and that we are surrounded from monocultures, we started from afar. However, including each year different small niches ecological benefits for several species, our site is today a place welcoming a diversity animal and plant species. Ladybugs, praying mantises and lacewings are insects formidable predators that we regularly observe in our gardens. Essentially, it was enough to make ecological services available to us.

But it is difficult to measure the result of our efforts and we often had to take other measures to avoid losses in our crops. At over time (and the damage incurred), we have learned how to prevent the onset of several diseases vegetables through targeted interventions at the right times. We also came from get to know most pests and have found a specific solution for each of them.
In general, we prefer control measures physical (floating openings, picking at pest hand, pheromone traps, sticky traps, etc.) and we only use natural insecticides as a last resort. These practices particulars are described in detail in the notes crops that are in the appendix, but let's say that overall, the effectiveness of our measures goes through a rapid diagnosis of problems. This is the key to good pest management and diseases in gardens.

A screening

Almost all of the "remedies" used in biological phytoprotection are effective in prevention, that is, they act on a situation before that the problems don't get too big. The fungicidal products allowed in organic farming will, for example, make it possible to protect new leaves of a plant on which a pathogenic fungus' is established, but not to suppress it. Natural insecticides, on the other hand, work best when used at specific times cycle of a pest. Spinosad, for example, is effective against leek moth, but only when its larvae descend from the plant.
When it comes to fungicides and / or insecticides, the timing is critical, as the success of the operation depends on it. Establish a good diagnosis of pests and diseases that are found in its cultures is therefore important. It is the role of screening, which involves daily observation cultures and changing risks.

 At our farm we have got into the habit of doing tour of the gardens before the start of each day of work. Given the proximity to all our plots, this short walk is not long. It allows us to detect anomalies that could be on the vegetables and to observe the most pressing maintenance needs. But still do you need to know what to look for ... to assist us in this task we use a service phytosanitary alert that informs us by email of diseases and insects to watch out for. It's a free service, offered by region and based on the know-how of professional researchers and scouts. Considering the quantity of vegetables that we cultivate, this service seems essential to me.

 We also have several manuals which deal with the main pests of crops, their cycles and the different spotting techniques. These are reference books that we let's keep it handy. Suggestions for books can be found in the bibliography.


 Rainy weather and the absence of sun for several consecutive weeks are often heralds of diseases in the gardens. Solanaceae and cucurbits are particularly susceptible to the arrival of harmful pathogens, but other vegetables like onions, beans and salads can also be achieved when the conditions climatic conditions are unfavorable to them for too long.

 Depending on the strain of infection, these diseases cause dysfunctions on the plants which slowly lead a crop to its loss. When a disease of vegetables appears, we first seek to determine the pathogen. In most cases, the foliage of the crop will show symptoms (stain, wilting, burning, yellowing, necrosis, etc.) that we will identify with the help of a guide. This is not always obvious, because several diseases can be simultaneously on the same foliage and certain symptoms can be confused with physiological disorders (deficiencies, water stress, etc.). In this case, the alert phytosanitary is particularly useful for us help to make a correct diagnosis, because, unlike in the books, it takes into account the current climatic conditions. Vegetable diseases can be viral, bacterial or fungal in nature. here are the main things to know about them:

Viral diseases are by far the least common and, to date, we have never had any in our gardens (I touch wood!). This type of disease is mainly spread by seed, hence the impossibility of purchasing good quality seeds. Garlic seed is particularly at risk, as everything such as commercial greenhouse tomato transplants. This is also one of the reasons that motivate us to make our own seedlings.

In case of bacterial disease, it is necessary to act quickly, because its virulence is sometimes surprising. This type of disease usually occurs in rainy weather and affected plants are usually found in groups because the bacteria are spread by contact. This is the reason for which we must get rid of by eradicating the diseased plants from the soil, taking care that they do not come into contact with other plants.
We then throw them in the trash, and after this work we even change our clothes. One of common symptoms of a bacterial disease is a rot that quickly turns into "Melting" of culture. Bacterial wilt that affects our cucurbit crops is probably the only bacterial disease that we encounter every year in our gardens.

Fungal diseases are, on the other hand, more common. To avoid them, the first precaution to take is to take care not to create lesions. Plants during harvest (from weeding to staking), because mushrooms need entry pmte to manifest. When comes the time to prune, it is really important to work on sunny days, because contact with water with an open wound creates the ideal conditions for the onset of diseases such as mildew.

When a fungal disease appears all of even, we carry out a weekly spraying of copper and sulfur, alternately. These applications are not curative, but when they are done on time, they allow the plants to continue their growth. These treatments are effective, but we are aware that they have reverse: copper can accumulate in soils and interfere with biological activity while sulfur has harmful effects on garden insects. We therefore want to turn to biological fungicides that introduce bacteria to fight against certain pathogenic fungi. We also seek to inoculate the planks of vulnerable vegetables with beneficial microbes that will protect plants from pathogens present in the soil. Unlike fungicides of mineral origin, these two methods strengthen the life of the soil rather than harming it.

With experience we have learned to do better look at seed catalogs to choose cultivars that are resistant to the diseases we have encountered in our gardens. These seeds are often more expensive, but they usually prevent the problem at the source. In greenhouses and tunnels, the choice of varieties of tomatoes and cucumbers resistant to viruses and diseases is especially important, given the humid climatic conditions and the lack of rotation of species.