Bacteria affecting tomato and pepper on all continents, particularly serious in open fields, in tropical, subtropical and temperate zones.
Harsh mainly on tomato, chilli and pepper.
Several species of Xanthomonas spp. are responsible for bacterial scab: X. euvesicatoria and X. gardneri on tomato, pepper and pepper; X. vesicatoria and X. perforans on tomato; X. campestris pv. raphani rarely on tomato.
Mainly observed in the open field.
Susceptible botanical family(s):
Solanaceae
Biology
Conservation : keep in the ground on plant debris, several months to several on the seeds. Develop on the surface or infect several cultivated, weedy or wild nightshades: eggplant, Amaranthus retroflexus, Datura stramonium, Chenopodium album, Portulaca oleracea, Galinsoga parviflora, Hibiscus trionum, Hyoscyamus niger, Hyoscyamus aureus, Lycium chinense, Lycium halimifolium, Physalis minima, Solanum dulcamara, S. nigrum, Nicandra physaloides, Lycopersicon pimpinellifolium, Nicotiana rustica , etc.
Infection : enter the leaflets through natural openings (stomata and hydatodes), via various wounds (broken hairs, growth cracks, insect bites, etc.
Development - Dissemination : invade the tissues and multiply there in large quantities. Dispersed by splashing water during rainfall and sprinkler irrigation. Infested micro-droplets can be carried over longer distances by the wind. Workers working in crops with wet foliage contribute to its dispersal. Contaminated seeds and plants also ensure their dissemination.
Favorable conditions : appreciate hot and humid production areas and are fond of high humidity following rain, storms and dew, and sprinkler irrigation.
Protection
Disease very difficult to control once symptoms have appeared in the crop.
Use resistant varieties and/or seeds of irreproachable sanitary quality, if in doubt, treat them using one of the following methods: hot, dry air, water at 50°C for 25 minutes, fermentation of the pulp and seeds for 4-5 days, soaking in a solution (acetic acid or hydrochloric acid or sodium hypochlorite, etc.
Carry out rotations of 2 to 3 years with non-host plants, especially cereals.
Promote plot drainage and avoid excess soil moisture.
Eliminate weeds and also be wary of spontaneous sowing of Solanaceae cultivated in plots where sheaths have been preserved.
Preferably plant in fairly well-ventilated plots.
Avoid too high planting densities in order to favor the aeration of the foliage.
Crops
