Psylla
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Psylla  Psylla are tiny sap-feeding pests that feed on flowers, young buds, and shoots of plants, sometimes resulting in distorted growth. These insects 1/10in (.3mm) long are red to green and resemble cicadas. They overwinter in tree crevices and ground litter and emerge in early spring to lay eggs in trees and shrubs/ For such a tiny insect pest, psylla can cause major damage. Also see pear psylla and boxwood psylla. Susceptible Plants- Pear, Boxwood, and a wide range of trees and shrubs. Symptoms- Leafs and blossom bud are damaged in the spring. Damage to fruit buds in late summer reduces the next years crop in fruit trees. In extreme cases, trees can die from "psylla-shock" caused by the buildup of a toxin injected into the plant as the psylla feed. Psylla also excrete a sweet liquid called honey-dew as they feed. Honey-dew is an excellent substrate for the growth of sooty mold which is the main problem associated with psylla feeding.
Prevention and Control- Prune off and burn infested shoots. Growing flowers such as corn marigold and cornflower attract natural predators. Smother overwintering adult psylla with dormant oil sprays such as Neem Oil Organic Pest Control
Later in the season, nymphs and adults prefer to feed on new succulent growth such as water sprouts. Pulling those sprouts from the trees helps with air flow, spray penetration, and light penetration, but it also takes out a large number of psylla nymphs. Leaving new shoots high in the trees is not wise as many nymphs and adults will congregate there and, in many cases, proper spray coverage does not occur at the tops of the trees. When psylla first become active in the spring, most egg-laying is done before buds open. Dormant oils kill some psylla outright, but more importantly, dormant oils keep female psylla from laying eggs early. When either the oil or the psylla's patience breaks down, spring eggs are laid in a short period of time and a more synchronous first generation of nymphs appears. The synchrony is important because a population mostly composed of early stage nymphs is easier to control than a mixed-stage population. The late stage "hard-shell" nymphs and adults are much harder to control with insecticides than the early stage nymph pyslla. Protectants- Surround Wp
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