Foliar nematodes occur in temperate regions, have a wide host range, and may be expected to occur in any region on susceptible plants. Infected but asymptomatic plants are probably the main source of infection. Adult foliar nematodes easily survive dessication in plant tissue and may remain viable in dead leaves for up to three years. They have a short life-cycle allowing a very rapid population increase. Affected plants should be removed and destroyed (do not compost). Hot water treatment at 50º C for 5-10 minutes may eliminate nematodes, but may also injure plant tissue. Weed control in greenhouse is important as many common weeds may become infected. There are no chemicals registered for postplant control in the United States. Note patch-like appearance of the injury with a distinct margin as the small nematodes cannot move through the leaf veins. Injury can be confused with insect feeding, fungal or bacterial diseases.