Bitterroot Restoration

The Litchi erinose mite (Eriophyes litchii) is a tiny pest (1/200 inch [0.13 millimeter] long) that cannot be seen without a microscope, but its damage on lychee is distinctive and often extensive. Leaflets become curled and distorted and have a velvety brown appearance. The mites begin their attack on new leaves at the onset of growth flushes. Early indications of their damage are small, wartlike swellings about 1/16 inch (1.6 millimeters) in diameter on the upper surface of leaflets and light yellow spots on the corresponding sites on the lower surface. Erinose mite damage seldom kills lychee trees, but is unsightly. Yield loss as a result of erinose mite damage has not been demonstrated.

Besides the erinose mite, the most common insect pests of lychee are the Cryptophlebia spp. (damaging fruits) and thrips and scales (affecting foliage).

The active stages and eggs are very small and may be difficult to find even with a X10 magnification hand-lens.

Young leaves are infested by adult mites that migrate from older infested leaves. They lay eggs on these leaves and the young hatch in 3 to 4 days. The life cycle is completed in 13 days under favourable conditions. The adults live in the velvety erinose produced on leaves as a reaction to their feeding. As trees produce new leaf and flower flushes, the mites migrate to these where they establish new pockets of erinose in which to feed and shelter.

Control:

• Satisfactory control can be achieved with a strict program of three successive sprays of dimethoate or wettable sulphur, targeting the growth flushes.
• Prune as much of the infested foliage from the tree as possible and destroy it. The mite is easily spread on nursery plants especially marcots taken from infested trees. Use only clean, mite free planting material. Spread can also occur by wind and bees.
• Several predatory mites and a fly larva prey on the erinose mite. However, none of these native Australian predators is able to control the pest.