.' .; -5r4lEPN0RT OF THE SOGIETV 5^ 14 1 



Family— ^Tetranycbidae (Red Spiders) 



''Red Spider '' (Tetranychus bimaculatus Hars'^ey) 



(Consult Bui. 416, U.S. Dep. Agr., 1917) 



A common pest in greenhouses on roses, violets, carnations, in the veg- 

 etable garden, and on many outdoor perennials, and a serious pest in, Western 

 Colorado on fruit trees, in Central California on hops, and in the Southern 

 States on cotton. 



Adult. — -Color of female variable — rusty green, amber, yellowish, 

 but more often brick red, with pigment blotches in the sides; legs pale 

 amber; palpi pale salmon; body oval, pear-shaped, 1/50 inch long; color 

 of male rusty salmon, body 1 /70 inch long. 



-Egg-s- — Spherical; clear becoming opaque; 50-100 eggs laid by each 

 female over a period of 7 to 12 days. Incubation period varies with the 

 temperature — 3 to 17 days. Laid singly on the under side of the leaves. 



Larval stage. — Six-legged, round and colourless; duration 2 to 17 days. 



First Nymphal Stage. — Eight-legged, oval, darker in colour; duration 

 2 to 4 days. 



Second Nymphal Stage. — Females only have this stage, elongate; dura- 

 tion 1| to 13 days. 



Feeding is done by means of sharp, slender, lance-like mouth-parts 

 thrust into the leaf, producing spotting. Fine webs are spun on the under 

 surface of the leaf, and these are probably protective. Reproduction is 

 both sexual and parthogenetic. 



Control. — Spraying with water, with lime-sulphur, nicotine sulphate 

 or miscible oil, or fishoil soap, potassium sulphide or kerosene emulsion; 

 dusting with finely resublimed sulphur. 



Clover Mite. (Bryobia pratensis Garman) 



This is a small red mite about 3/100 inch long which injures the leaves 

 of clover, apple and other orchard and forest trees by puncturing the tissues, 

 causing them to become yellowish and sickly. The winter is passed in the 

 egg stage, and the small round red eggs can be readily recognized in the 

 crotches of fruit-trees. There are several generations in a season. In 

 autumn it sometimes invades houses. 



