Why Does My Pear Look Unhealthy?

Does the fruit have olive-brown, corky spots that turn dark brown?

Does the fruit have holes surrounded by brown, crumbly excrement?

Is the fruit covered with a shiny, sticky coating that turns black?

Did the leaves suddenly blacken and the tips of growing shoots bend over?

Did the leaves suddenly blacken during fall?

Do the leaves have small, round, dark spots with purple margins?

Are the leaves covered with lacy brown patches?

Do the leaves have small brown blisters on undersides?

Fungal disease called Pear scab often causes problems for pear fruits. It also causes dark, velvety patches on leaves. It overwinters on fallen leaf litter and infected twigs and spreads to the tree in the spring. To control pear scab, remove old leaves from beneath trees and compost or bury them. Prune out infected twigs that bear small, blister-like pustules. Lime-sulfur applied early in the growing season also helps control the disease.

Codling moth larvae are the most likely culprits. These fat, white-pinkish caterpillars tunnel through the fruit. For light infestations, kill eggs by spraying superior oil on leaves and twigs within 2-6 weeks of blossoming. For heavy infestations, kill larvae before they tunnel into fruit by spraying the tree canopy with pyrethrin at petal fall and again 10-14 days later.

These symptoms usually indicate the activity of Pear psylla. These tiny red or green, winged insects overwinter in tree crevices and ground litter and emerge in early spring to lay eggs. To control psylla, spray overwintering adults with dormant oil in late winter before spring growth begins. During the growing season, kill eggs and insects with superior oil spray or insecticidal soap.

These symptoms indicate the bacterial disease fire blight. Control fire blight during the growing season by pruning off branches a foot below infected sections. Between each cut, dip pruning shears into isopropyl alcohol or a 10 percent bleach solution to prevent the disease from spreading as you prune.

The bacterial disease Pseudomonas blight appears during cool fall weather and creates oozing cankers. Control pseudomonas blight during the growing season by pruning off branches a foot below infected sections. Between each cut, dip pruning shears into isopropyl alcohol or a 10 percent bleach solution to prevent the disease from spreading as you prune.

These symptoms usually indicate the fungal disease Fabraea leaf spot. This disease may cause leaves to turn yellow and drop, weakening the tree. Since the disease overwinters in twig cankers as well as fallen leaves, garden sanitation does little to control the disease. Copper spray, applied when leaves are half out and then once or twice again at 2-week intervals, offers some control.

Pear slugs cause lacy brown patches on pear leaves. These green-black, slimy creatures are not true slugs; they’re the larvae of the pear sawfly, a black-and-yellow insect slightly larger than a housefly. Remove them by handpicking or with blasts of water. For severe infestations, use insecticidal soap spray.

These symptoms usually indicate the activity of Pearleaf blister mites. You can find them inside the blisters if you use a magnifying glass. Damage usually is cosmetic and can be ignored, but if control is necessary, spray lime-sulfur before buds open or superior oil as buds swell.

If the leaves have turned yellow and limbs have died back you might need to face a San Jose Scale. Clusters of these sucking insects cling to the bark and appear as small gray bumps that can be easily scraped off with a fingernail. Control them with late winter application of dormant oil spray.