Silvery streaks

Snails and slugs feed on plants at night. They tear holes in foliage, fruits, and soft stems, using a rasp-like tongue. They may eat entire seedlings. As they move, snails and slugs leave a slime-like mucous trail which dries into silvery streaks. These streaks are undesirable on floral and ornamental crops and on those portions of crops to be sold for human food. 

Flowers deformed leaves and petals with white flecks. Cause Thrips. Gladiolus thrips are a very destructive common pest. These V25", yellow to black, flying insects feed by rasping petals and leaf surfaces, leaving silvery spots and streaks. They hide under leaf sheaths and inside flowers. Other symptoms are partial bloom, failure to bloom, and shriveling. Thrips wastes may appear as black spots on the undersides of leaves. Infested corms are dark, sticky, and rough. 

Damage Adults and nymphs suck contents of plant cells from a variety of garden plants, flowers, fruits, and shade trees. Their feeding leaves silvery speckling or streaks on leaves severe infestations stunt plants and damage flowers and developing fruit some species spread tomato spotted wilt irus. 

Burnt streaks are caused by thermal damage to the melt. The result can be a decrease of the length of the molecule chain (silvery discoloration) or a change of the maeromolecules (brownish discoloration). 

Top left Glass fibre streaks clearly visible weld line Top right Moulded part with rough silvery surface Bottom Glass fibre streak due to orientation near sprue... 

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