Crops
Main measures and methods of protection
limiting fruit receptivity
and the installation of microorganisms
Main methods limiting primary or secondary installations
microorganisms that cause rots on tomato fruits
pre- and post-harvest
| Possible methods | Expected effects |
| Before and during cultivation | |
| Use tolerant varieties. | Tomato varieties can exhibit several types of behavior with regard to fruit rots: - lower sensitivities, often non-specific, associated for example with less receptivity of the fruits (more grouped maturity, less fragile cuticle, less porosity of the stalk scar, better adaptation to stress ); - more or less high resistance, rather specific to Phytophthora nicotianae (partial polygenic resistance, monogenic resistance conferred by the gene, resistance derived Br from Lycopersicon esculentum var. 'cerasiforme' ), Rhizoctonia solani (several resistances involving at least 4 major genes one case or 2 genes in the other), Alternaria alternata (also derived from an accession of Lycopersicon esculentum var. ' cerasiforme '. |
| Grow the plants on mounds. Choose favorable planting densities to a good ventilation of the culture. Stake the plants or grow them on a grid. Orient the rows in order to favor maximum ventilation relative to the prevailing wind. Remove the lower axillary branches. |
Prevents the fruits from coming into contact with the ground, thus preventing certain contaminations ( Phytophthora nicotianae , Rhizoctonia solani , Sclerotium rolfsii , Pythium spp.). Promotes aeration of vegetation. |
| Control fertilization, especially nitrogen. | The larger fruits, from crops with high nitrogen fertilization, appear to be more susceptible to rots. |
| Manage irrigation in order to limit maximum wetting of plants (localized irrigation is preferable), and avoid water stress. |
The presence of water on the foliage and fruits promotes the dispersion of the inoculum and contamination. |
| Apply fungicides. | Several fungicides are recommended in the literature to fight against certain rotting agents (especially Alternaria alternata ) ( e-phy ). One to three applications are made in the weeks leading up to harvest, sometimes taking into account the trends defined by the Tom-Cast forecast model. |
| Apply natural substances. | Various preparations have been tested to limit the development of certain rotting agents: vapors of essential oils of lemon, extracts of Withania somnifera , garlic, onion, Dennettia tripetala , Azadirachta indica |
| Apply various microorganisms. | Some yeast-like fungi ( Pichia onychis, P. anomala, Debaryomyces hansenii ) or not ( Trichoderma hamatum, Gliocladium virens ) have been shown to be antagonists and competitors with regard to several rotting agents. |
| Remove spoiled and rotten fruit plots and destroy them or export them far from them. |
These fruits constitute an important potential inoculum, visited by vector insects and from which contaminations can take place through drafts and splashing water. |
| Clean and disinfect equipment and containers for harvesting and transport the fruits. |
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| After harvest | |
| Clean and disinfect equipment and premises used to store fruit. |
These measures contribute to the elimination of the nutritive bases allowing the microorganisms to be maintained, and thus to decrease the pressure of inoculum in the environment of the harvested fruits. |
| Add active chlorine to the wash water; this must be at a pH greater than 6.4. |
This product has a well-known disinfectant effect whose effectiveness is well established. Other treatments have been tested to eliminate the germs present on the fruits, this with more or less success: hot water, gamma rays or UV-C R |
| Do not leave the fruits submerged for more than 3 minutes. |
Beyond this period, infiltrations take place leading to more contamination. |
| Sort and eliminate rotten fruit. | This avoids storing tomatoes which will undoubtedly lead to contamination from rotten fruit to healthy fruit after harvest. |
Main methods of decreasing the receptivity of tomato fruits
microorganisms responsible for pre- and post-harvest rots.
| Possible methods | Expected effects |
| Before and during cultivation | |
| Do not choose a production schedule running fruit risk of cold damage or harvest them at an advanced stage of maturity. |
The effects of cold and advanced maturity allow many secondary microorganisms to invade the fruits. They should therefore be avoided. |
| Avoid various injuries related to production techniques, to their handling, their packaging, their storage (punctures, bursts, bruises, scratches ...). |
These wounds promote the penetration of many microorganisms that cause rotting, in the field as well as in the post-harvest. See specific information and / or apply the data recommendations for Slots growth , the microcracks , damage due to various pests ( caterpillars of moths , bugs ...), the damage caused by leaf blight , the necrosis apical and Cold. |
| Protect and maintain as much as possible vegetation in place. |
Maintaining a quality plant cover will protect the fruits from external aggressions (sun, water, etc.). |
| Harvest carefully and use equipment respecting the fruits as much as possible. |
This will avoid causing injuries, bruises, which would subsequently facilitate contamination by rotting agents. |
| After harvest | |
| Store fruits in warehouses rather cool but not at a temperature below 12 ° C. |
Storing fruits at high temperatures promotes the development of rots. |
| Avoid the presence of free water on the fruits, after washing or following condensation. Let them dry well. |
The free water on the fruit and the humidity promote both bacteria and fungi responsible for post-harvest rots. |