What causes the brown spots on pears?


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Post by CoolJay221 » Wed Feb 15, 2006 4:13 pm

OVERALL APPEARANCE Symptoms: Cause: Solution:
Numerous small holes are found in stem and branches. Ambrosia Beetles (see above). Simply click on the pest for more information and controls.
Fruit and leaves have a blackened appearance. Mature insects are winged, green to black in colour and jump from leaves when disturbed. Immature very small, flattened yellow to black insects usually found in a drop of honeydew on the underside of leaves. Pear Psylla. There are several generations per year. Spray Diazinon during pink bud stage but before any blossoms have opened. During the growing season spray when honeydew drops are noticed and repeat at 12-day intervals. Use Diazinon or Sevin.

on LEAVES, BRANCHES and STEMS Symptoms: Cause: Solution:
Rolled leaves and green worms (12 mm) with brown or black heads are found hiding inside. Leafrollers Simply click on the pest for more information and controls.
Small reddish-brown spots on bark develop into cracked, sunken and shriveled cankers (5 - 10 cm or longer). Eventually thye canker falls out leaving fiberous material. Anthracnose Canker (fungus) In March, prune out and burn infected branches. Spray Fruit-Guard before or after blossoms will help control this disease. After harvest apply Copper Spray.
Dark brown spots and dead areas develop on bark. Eventually they will girdle twigs, branches and limbs. Open cankers have concentric rings of raised tissue. Red, round fungal fruiting structures can be found on the cankers during the second winter and spring. European Canker (fungus) Prune off and burn branches. Cankers should be cut out and burned as well. Spray Copper Spray before fall rains and again when leaves are falling off the trees.
Whitish, grey substance on leaves, branches and fruit. Powdery Mildew (see above). Simply click on the pest for more information and controls.
Leaves are skeletonized (lacy) and turn brown. Slimy, slug-like green to black worms (7 mm) can be found on the leaves. Pearslugs. The larvae of Sawflies. In Spring if problem is severe spray with Diazinon or Methoxychlor.
Leaves and branches darken, wilt and die. Discoloured areas develop on twigs and branches. Fire Blight (bacterium). Not a problem in coastal areas. Prune off and burn infected branches. Cankers should be cut out and burned as well. Disinfect pruning tools (dip in solution of 1 part bleach / 10 parts water) before every cut to prevent spreading the disease. Spray Copper Spray in late May to June. Do NOT use this on ANJOU pears.
Orange spots appear on leaves. Pear Trellis Rust. This disease also affects Junipers. Do NOT plant Junipers close to Pear trees. Destroy, old infested Junpers before April and pick off infected Pear leaves before August to prevent infection.
Small brown blisters and dead spots on the undersides of leaves. Pearleaf Blister Mites. Lime Sulphur before buds open.
Very small, hard and round bumps with dull-yellow centers on bark. Red to purple spots may be visible on fruit and new shoots. San Jose Scale (see Scale Insects above) Spray bark and limbs with Dormant Oil before buds open or Diazinon or Malathion when crawlers are present.
Leaves have small, brown spots with tan centers. Frog-eye Leaf Spot (fungus). See also Black Rot on fruit. Use Fruit Guard after blossoms and repeat in 2 weeks and again after heavy rainfall.
Use a dormant spray in the dormant season.
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