Crops
Colletotrichum coccodes (Root rot)
Responsible especially for Anthracnose of tomato fruits, Colletotrichum coccodes , a very cosmopolitan fungus and pathogenic on a wide range of hosts, also attacks its root system ( black dot ). Like P. lycopersici , it is present in many market garden soils in which rotations too often bring back sensitive crops such as peppers, potatoes and tomatoes especially. This situation contributes to gradually increasing the rate of inoculum in the soil. Its most significant damage to roots is observed in particular under shelter, both in soil and in soil-less cultivation.
The root systems are rather dull and have few rootlets and secondary roots (figure 1), these, atrophied or rotten, have disappeared. Lesions, greyish to brownish at first, more or less extensive are also visible on the cortex of large roots (Figure 2). This gradually takes on an increasingly brown color, decomposes and is partially covered with black microsclerotia (figure 3 to 5) sometimes bristling with black bristles (visible with a magnifying glass) (figures 6 and 7). Ultimately, the cortex, rotten and punctuated with sclerotia, easily detaches from the central cylinder; the latter is colonized at the end of the course of the disease, taking a blackish tint and being able to present numerous microsclerotia. Note that in soilless culture, the tissues tend to discolor.
This fungus is considered by some authors as a secondary invader of more or less decomposed old roots. It should be noted that they are frequently observed on roots in complexes with other pests that could favor its installation on them: P. lycopersici, R. solani, Fusarium oxysporum f. sp. l ycopersici, Pythium spp., Meloidogyne spp. ... We should add that the significant attacks observed in certain farms, both in soil and above ground, could sometimes encourage us to reconsider its parasitic status; the recent attacks observed in particular on several rootstocks in several countries of the Mediterranean basin, however, confirm its parasitism.
Colletotrichum coccodes thought to is be capable of causing brown circular lesions on leaflets, haloed with a yellow halo, and of infecting the stems.
For additional information on this fungus, you can consult the sheet Colletotrichum coccodes .
The root systems are rather dull and have few rootlets and secondary roots (figure 1), these, atrophied or rotten, have disappeared. Lesions, greyish to brownish at first, more or less extensive are also visible on the cortex of large roots (Figure 2). This gradually takes on an increasingly brown color, decomposes and is partially covered with black microsclerotia (figure 3 to 5) sometimes bristling with black bristles (visible with a magnifying glass) (figures 6 and 7). Ultimately, the cortex, rotten and punctuated with sclerotia, easily detaches from the central cylinder; the latter is colonized at the end of the course of the disease, taking a blackish tint and being able to present numerous microsclerotia. Note that in soilless culture, the tissues tend to discolor.
This fungus is considered by some authors as a secondary invader of more or less decomposed old roots. It should be noted that they are frequently observed on roots in complexes with other pests that could favor its installation on them: P. lycopersici, R. solani, Fusarium oxysporum f. sp. l ycopersici, Pythium spp., Meloidogyne spp. ... We should add that the significant attacks observed in certain farms, both in soil and above ground, could sometimes encourage us to reconsider its parasitic status; the recent attacks observed in particular on several rootstocks in several countries of the Mediterranean basin, however, confirm its parasitism.
Colletotrichum coccodes thought to is be capable of causing brown circular lesions on leaflets, haloed with a yellow halo, and of infecting the stems.
For additional information on this fungus, you can consult the sheet Colletotrichum coccodes .
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