Several scales including San Jose scale and Forbes scale may infest pears.
Control: Apply a 3% oil spray about January 15 to 20. To make a 3% oil spray, mix 3 1/3 gallons of 90% oil concentrate in 100 gallons of water. (½ cup in 1 gallon of water). Superior type oils (not mayonnaise or dormant type) also are available. Use according to directions on the label.
These make webs or tents over the twigs and foliage, and may attack pear trees. They feed in colonies on the leaves within the web. When they need additional food, they enlarge the web.
Control: Use the biological control, Bacillus thuringiensis, it is available under many brand names such as Dipel, LARVO-BT, Cutlass, Javelin WG and Biobit. Spray with 2 pounds of 50% Sevin wettable powder per 100 gallons of water or 2 tablespoons per gallon. Do not apply Sevin within 1 day of harvest.