VEGETABLE INSECTS. 



80 



riVo 



OTHER OKRA PESTS. 



Aulacaspis pentagona, the West Indian peach scale, occasionally 

 attacks the stalks and branches; tire ant, feeds on the flowers and 

 young growth (see Eggplant, page 296); plant lice occur on the 

 undersides ot the leaves (for control see Cabbage Plant louse, 

 page 283). 



ONION. 



THE oxiux THRiPs {Thvips tohaci). 



The drying up and withering of the tips of the onion leaves, so 

 commonly seen in onion patches, is caused chiefly by the activities 



5)f this little in- 



L^'-^-itB^ 



i;ect called the 

 onion thrips. 



It is one of 

 the most de- 

 structive of the 

 vegetable- feed- 

 ing thrips and 

 attacks a wide 

 variety of 

 plants. The 

 adult insect is a 

 slender elongate 

 little creature, 

 about one twen- 

 ty-fifth of an 

 inch long, and 



Fig. .57! — Mustard I'dd P>()i(M-. Adult nidth and larva on pod. 



two pairs of del- 

 icate wings fringed with hairs. It is pale yellow^ in color. 



This insect causes (laniagc hy ]-asping or chafing the leaf surface, 

 causing the atTected p(n'tion to die and shrivel up. 



The very ininnte eggs are inserted singly within the leaf tissue 

 and hatcli in about iom- (htys. The young are wingless and almost 

 trajisparent ;it tirs1. hut hiter change to a greenish-yellow. They 

 feed togetlier in groups, and i)ass through a number of changes in 

 form before becoming adults. 



Control. — These thrips are rather difficult to control owing to the 

 difficulty of liitting them with a spray solution. Good results may 



