INJURIOUS AND BENEFICIAL INSECTS OF CALIFORNIA. 



15 



Life History. — The eggs are suspended upon minute stalks with 

 threads as supports. They hatch in from nine to twelve days, being 

 laid from May on throughout the warm summer months. The first 

 born are six-legged, but after the first molt acquire another pair, 

 making the usual number. In two weeks they are full grown and 

 begin egg-laying. They live from thirty to thirty-five days, thus 

 making the life cycle cover a period of about six Aveeks. By far the 

 greater numbers occur during the warm summer months, when most 

 of the damage is done, but much damage often occurs until late in 

 winter. On deciduous fruit trees the eggs are deposited at the bases 

 of the last year's shoots and do not hatch until the following spring. 



Nature of Work. — This mite besides producing the whitish mottled 

 effect upon the leaves also causes similar markings upon the fruit. 



Distribution.— The citrus red spider occurs throughout the State. 

 It is very common in the southern part and was taken in Humboldt 

 County in 1914 by Geo. P. Weldon. where he found it upon apple trees. 



Fig. 16. — The citrus red spider, Tetranychus mytilaspidis Riley. Greatly enlarged 

 to show tubercles at the bases of the spines on the back. (After Volck, Cal. Agrcl. 

 Exp. Sta.) 



Food Plants. — Though primarily a citrus pest, attacking the citron, 

 grapefruit, lemon, orange, tangerine, etc., it also feeds upon the foliage 

 of the apple, peach, pear, prune and other deciduous fruit trees. 



Control.— As in the case of other mites, much experimental work 

 has been directed against this species, particularly in the citrus 

 orchards of both the northern and southern parts of the State. A 

 1 wo and two and one half per cent solution of commercial lime-sulphur 

 have been used in the past with very good results, except in hot, dry 

 weather, when some burnings have resulted. The addition of four 

 gallons of flour paste to 100 gallons of the above spray has been found 

 by J. D. Neuls 8 to make this spray much more efficient by spreading it 

 more evenly upon the surface of the leaves and fruit and preventing 



'Mo. Bui. Cal. Hort. Com. II, 557, 1913. 



