A.Slugs
Hostas seem to be pest free. However, Deer, slugs do enjoy eating in the leaves of hostas.
The significant problem that is occurring on occasion is crown rot. In the South this rot will become a problem in the summer when the extreme heat, humidity, and moisture cause the crown to rot and the leaves to pull off the plant. In the North, this problem is visible in the early spring because water has sat on the Hosta crown during the winter and the plant fails to start growing.

B.Foliar nematodes
A problem that is becoming more widespread every year. In cases of nematode attack, the microscopic worm feeds on the leaf tissues between the veins of mature leaves, eventually causing the entire leaf to die. Sanitation is the best control.Foliarnematodes Foliar nematodes (Aphelenchoides fragariae) are microscopic roundworms (0.5-1.0 mm long can’t see by eye), they live, feed and reproduce inside the tender tissue of hosta leaves. Foliar nematodes spread by contact between plants in the presence of water. FoliarnematodesThey can enter through leaf pores or stomates or by puncturing the leaf surface with their stylet, a needle like organ used for piercing and feeding. As it moves within the leaf, it kills cells causing them to brown leaf like burning. These nematodes can survive on soil fungi and overwinter in the soil as well as in plant debris. When moisture becomes available again They are not killed by winter’s cold unless the plant is killed. There are few chemical controls. With nematicides labeled for nursery use, these products are EXTREMELY toxic, especially to fish and wildlife, So,sanitation and use good hygiene in the garden is very important to prevent them when found in your garden kill and burn your plant is good recommend.

C.Hosta Virus X
A new pest that causes the leaves to become mottled and twisted. This deformity has no cure. If your plants contact this virus, also called HVX, the plant must be destroyed. Fortunately, it does not easily spread to other hostas in your garden.

D. Southern bright
A fungal disease that causes the base of the leaves to rot, it turn causes leaves to turn yellow, collapse, and die in finally. Usually notice in you garden, remove it ASAP when you found, burn or deeply bury disease plant. Dig out and replace the soil. Do not forget to sterilize all tools to reduce spreading of disease.

E. Voles and Moles
Voles are like mice that have short tails and burrow in the soil like moles.voles prefer to eat fleshy roots such as those found on Hostas. Voles can kill an entire hosta garden over winter. Control it by baits and traps.

Moles are about 7 inches long with distinct paddle shaped feet and long claws. They live underground and can tunnel up to 18 feet in one hour
Moles are about 7 inches long with distinct paddle shaped feet and long claws. They live underground and can tunnel up to 18 feet in one hour

F. Deer
Hostas also appeals to deer. In areas where people and deer must coincide, hostas are often sought out by deer as browse. Many homeowners resort to repellents to drive deer away from their landscaping.
Milorganite is an organic nitrogen fertilizer derived from heat-dried microbes that have digested the organic material in wastewater. The odor from milorganite is effective at keeping deer away from your gardens.

G.other case that cause leaf damage
Hail damage / frost damage / sun burn or heat stress

Hail damage

Damage will destroy lave of plant if you garden was beat by hail storm the best way to cut off all hosta leave to the ground and waiting for new re growing leave.