It may be signs of bacterial leaf spot (
http://www.apsnet.org/edcenter/intropp/lessons/prokaryotes/Pages/Bacterialspot.aspx), but i am not 100% sure, someone else maybe be able to confirm it.
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from the website
Because the most obvious symptoms occur on leaves, the disease is often referred to as "bacterial leaf spot." Symptoms begin as small, yellow-green lesions on young leaves which usually appear deformed and twisted (Figure 8), or as dark, water soaked, greasy-appearing lesions on older foliage (Figure 9). Lesions develop rapidly to a size of 0.25 to 0.5 cm (0.1 to 0.2 in.) wide and become tan to brownish-red. Lesion shape is defined by leaf veinlets, so the shape is angular rather than the round shape that is more typical of fungal leaf spots or injury caused by some pesticides or other chemical sprays.
Lesions often are more numerous at the tip and margin of the leaf where moisture such as dew is retained (Figure 10). Under dry conditions, diseased leaves can develop a tattered appearance as the leaf margin and lesion centers become necrotic, dry up and disintegrate. Lesion size is often larger and symptoms are more severe when extended periods (> 12 hours) of moisture-saturated tissue occur.
