SCORPIONS, SPIDERS, MITES AND TICKS 213 



spider, " often does much damage to fruit trees, particularly 

 on the Pacific Coast. The eggs are laid on the branches of 

 the tree, where they remain over winter, the young mites 

 issuing about the time the leaf buds open. They may be 

 controlled by spraying the eggs with the lime-sulphur wash 

 (see page 415) just before the eggs hatch in the spring, or by 

 spraying or dusting with sulphur. This same species is often 

 an important pest on clover and grasses and is then known as 

 the clover-mite. In the Mississippi Valley states they some- 

 times swarm into dwelling houses late in the fall. Dry sulphur 

 dusted around the windows and doors or other places where the 

 mites enter the house, or the free use of pyrethrum after they 

 have gained an entrance, will give relief. 



Two other red spiders, Tetranychus mytilaspidis, and 

 T. sexmaculatus, are serious pests of citrus trees. They are 

 controlled by dusting the trees thoroughly with finely powdered 

 sulphur. 



The blister-mites, Eriophyes, are minute whitish, grub-like 

 creatures that bore into the tissue of the leaves of many plants. 

 The pear-leaf blister-mite is perhaps the most important of 

 these. They spend the winter in the buds and as the leaves be- 

 gin to develop they make their way into the tissue, causing 

 green or reddish blisters. They may be controlled by spray- 

 ing during the late fall or early spring with kerosene emul- 

 sion diluted with five parts of water, or with the lime-sulphur 

 wash. 



Of the mites that attack man, the young harvest-mites, or 

 "jiggers", are probably the most familiar. Normally these 

 little mites live on plants, but when opportunity offers they will 

 crawl on man or any other animal and burrow into the skin, 

 causing intolerable itching. Where these mites are trouble- 

 some, one should avoid sitting or lying on the grass or in 

 other places where they may occur. Harvest men and others 

 whose work exposes them to these pests may get some relief 

 by dusting sulphur in the underclothing and shoes, and 

 by bathing, using a strong carbolic or tar soap, as soon as they 

 return from the fields. Sulphur ointments are also used. 



The minute, almost round, whitish mites, Sarcoptes scabiei, 



