The symptoms of wilt virus disease of tomato ( Tomato spotted wilt virus , TSWV) on tomato are very varied.
The leaflets and leaves may present a mosaic more or less marked . Small can also be distinguished chlorotic to necrotic brown spots , more or less scattered over the entire blade (Figures 1 to 4). Brown rings are sometimes visible on the latter (Figures 5 and 6). Red to brown patches tend to concentrate and coalesce at the base of the leaflets. In some cases the leaves turn anthocyanin colouration. Occasionally, elongated necrotic lesions are visible on the petioles.
Subsequently, the affected areas spread and the leaflets, rather chlorotic, take on a tan tint which is the origin of the name "bronzed tomato disease" (figure 7). The same is true for necrotic spots which merge and cause necrosis and drying out of entire leaflets. Of necrotic lesions (streak) may appear on the petioles and stems . After several weeks, the diseased feet may be completely necrotic. Sometimes wilting is observed.
It should be noted that the growth of plants is strongly affected. When it is not blocked, it does not always happen symmetrically; in this case, we can observe an apical curvature (called " vira cabeça " by the Brazilians). Note that plants can also be chlorotic.
When the infection occurs before the appearance of the first bunch, no fruit develops. If fruits are already present, they undergo deformation and see their growth reduced . Large arabesques and rings, sometimes concentric (figures 8 and 9), discolored areas sometimes tanned, dry and cracked necrotic spots (figures 10 and 11) are then also visible. Ripe fruits are also distorted and poorly colored, showing internal browning. It is obvious that these various alterations make the fruits unmarketable.