Protection methods

Although the incidence of Setophoma terrestris on melon crops is still poorly appreciated in France and probably limited, it may be advantageous to deal with its parasitism to implement the protection methods recommended to control Pyrenochaeta lycopsersici .

• During cultivation

If you observe symptoms of pink roots, it is unfortunately too late to intervene effectively on the crop. Indeed, there is no effective way to eliminate this pathogen present on the roots.

In order to try to keep the plants alive as long as possible, you should:
- to butter them in order to promote the emission of adventitious roots which can replace the old damaged roots;
- to bathe them during the hottest periods of the day to avoid excessive and uncompensated evaporation, leading to wilting, drying out and death of the plants;
- monitor carefully the irrigation . Indeed, if the plants wilt, it is not necessarily linked to a lack of water, but rather to root alterations due to S. terrestris . In some cases, growers tend to increase irrigation to respond to wilting, leading to amplification of root lesions through asphyxiation.

Note that no fungicide * is authorized for this use on melon.  

We also advise you to eliminate and destroy carefully diseased plants and their root systems, in progress, but especially at the end of cultivation. This will prevent them from being subsequently buried in the soil and from enriching the inoculum of S. terestris already present.

• Next crop

The crop rotations are interesting when performed preventively, before the soil is heavily contaminated. In the latter case, their effectiveness is relative because the fungus is stored there for a long time. In addition, it can multiply there thanks to various alternative hosts. Of course, sensitive plants should not be introduced into the rotations. The soil must be well worked, a good subsoil will allow the roots to access new layers.

Heavily contaminated soils should be disinfected . A fumigant may be used ( e-phy ) (dazomet). If this fumigant is more or less effective, however, it poses material problems and leads to a number of disadvantages:
- destruction of natural microorganisms antagonists of certain pathogenic agents;
- increased receptivity to parasites in disinfected soil;
- appearance of toxicity phenomena (excess of exchangeable manganese, excess ammonia following a complete or partial blockage of the nitrification ).

In sunny regions, solar disinfection of the soil (solarization or pasteurization) is increasingly used to control S. terrestris, in particular in onion crops. It consists of covering the floor to be disinfected, which will have been very well prepared and moistened beforehand, with a polyethylene film 35 to 50 µm thick. This is kept in place for at least a month at a very sunny time of the year. This method is economical, efficient, and makes it possible to control the colonizing fungi of the superficial zone of the soil. Steam disinfection is also effective.

Failure to disinfect the soil can delay attacks by S. terrestris by placing the plants in warmed soil and / or by increasing the volume of the clods which will be prepared with a healthy substrate.

On the other hand, grafting should be an effective solution if you use a hybrid squash between Cucurbita moscata rootstock and Cucurbita maxima as .


* Chemical control : As the number of pesticides available for a given use is constantly changing, we advise you to always confirm your choice by consulting the e-phy site of the Ministry of Agriculture and Fisheries which is an online catalog of plant protection products and their uses, fertilizers and growing media approved in France. This also applies to all biological products based on microorganisms or natural substances.