70 



should be turned away from the plants for this purpose. They pos- 

 sess the advantage of also acting as a stimulant to plant growth. 

 Stable manure is apt to induce infestation, as this species is well known 

 to develop in excrement and other decomposing material. As soon 

 as plants show signs of wilting and maggots are known to be present, 

 the injured plants should l)e promptly pulled and destroj^ed. 



The above methods have been used with success against onion mao'- 

 gots and similar root-feeding species, and may be all that is required 

 in the case of ordinaiy infestation of beets. 



One of the best remedies for root maggots is bisulphid of carbon. 

 It has been used with more or less success by Prof. A. J. Cook and' 

 others since 1880. In its application great care should be exercised 

 that the liquid shall not come in direct contact with the roots of the 

 affected plants. Directions for the treatment of plants affected b}" 

 root maggots are furnished on page li of Farmers' Bulletin 14.5. 

 a copy of which can 1je had upon application to the Secretary of 

 Agriculture. 



THE RED SPIDER. 



The common or two-spotted red spider {Tetranyc/uis Inmaculatus 

 Harv.) is usualh^ present in most fields of sugar beet east of the Rocky 

 Mountain range, but it is preeminently a greenhouse pest, and as a 

 rule does comparatively little injury to plants growing out of doors. 

 It is unique as a vegetable pest in that it is not a true insect, nor even a 

 spider, as the popular term M'ould imply, 1)ut a spinning mite. As the 

 word mite indicates, these creatures are extremely minute, and are 

 frequently not noticed until they become excessively numerous, as is 

 apt to happen during summer droughts. They do considerable dam- 

 age in flower and vegetable gardens, but attain their greatest destruc- 

 tiveness in connection with j)lants grown under glass. 



The general appearance of the common red spider is shown in figure 

 05, highly magnified. The length of a full-grown individual is only 

 about one-fiftieth of an inch. The ground color is reddish, usually 

 more or less tinged with yellowish or orange, and most individuals 

 have a dark spot on each side, due to the food contents of the body. 

 The young are similar to the adults, differing in having only three 

 pairs of legs, while the adults have four. This red spider spins threads, 

 but does not use them for climbing. The threads are frequentlj' so 

 numerous as to form a tissue visible at a little distance. Webs are 

 usually constructed on the under sides of leaves and within them the 

 mites feed and lay their eggs from which the 3'Oung develop. 



This red spider is quite likely of foreign origin, but its distribution 

 has not been carefulh' studied. 



It is inclined to be omnivorous, attacking a wide range of jjlants. 

 As the red spiders increase in number the leaves of an affected plant 



