EUROPEAN RED MITE
It is a major fruit tree pest which attacks apples, pears and other stone fruits in Himachal Pradesh. The females are long and have eight legs. They are about 1/64 inch long and bright red in color. Males are smaller and lighter in color and have pointed abdomens. In winters eggs are rounded and bright red in color. In summers these eggs are pale yellow. In winters eggs are generally laid in the barks or the crevices of the apple tree and these eggs are hatched in spring when trees bloom. It can not be seen with naked eye as they are very small, so help of hand lens is needed. During growing season eggs are laid on the leaves. Each female is capable of laying 35 eggs during her average life span. There are about 8 to 10 generations of mites per year.
The European red mite causes injury to the tree by feeding on the leaves and hence removing the leaf tissue. It destroys the chlorophyll and increases respiration. Injury to the leaf takes place when mite put its mouth into the leaf cell to withdraw its contents. The mite prefers the lower leaf surface but can be seen on the upper surface when populations are high. The leaves turn to brown and in severe cases it turns into bronze color. When leaves are heavily infested trees produce fewer or less vigorous fruit buds and reduce the ability of the leaves to make enough food for the desirable sizing of the fruit. Mite can also affect the fruit color and can result in premature fruit drop. If neglected the mite can make the tree weak and hence lesser production of apples.
In dormant season monitoring can be done by collecting 5 spurs per tree on randomly selected 10 trees in each block of the orchard. Look out for the no. of eggs on each spur starting from the base of the bud with the help of hand lens. In summer monitoring is especially important if you have applied any broad spectrum insecticide like Chlorpyrifos. Application of such insecticides increases the risk of mite damage in current year. Examine leaves throughout the orchard to determine what average no of mites are present on each leaf. Inspections can be done with the help of hand lens.
It can be applied by encouraging natural enemies that feed on European red mite. With the help of natural enemies the cost of managing European red mite can be reduced.
- Avoid pesticides that are toxic to natural enemies,
- Do not try to eliminate the whole population of mite which can risk the killing of predatory mites
The natural enemies include
Mites can be controlled by application of dormant oil in dormant season. If dormant oil is not done, apply horticultural mineral oil in early spring to control it.
- Hexythiazox (kills eggs need to apply early)
- Dicofol (for use on late season mite out-breaks)
Rotate miticides within the same season. Do not use the same chemical over time.