1496 



ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 



(iraiii or Stni» ln-rrj Tlirips 

 Eutttrips tritici Fitch 

 General Appenraiice 



Very minute, beini; Irom 0.0-9 to 0.031 

 of an inch in length. The color is yellow, 

 with orange-tinted thorax. 



Life History 



The eggs are very minute, globular in 

 shape and red in color. They are insert- 

 ed within the tissues of the host and 

 hatch within a few days. The nymphs or 

 young greatly resemble the adults, and 

 begin to feed at once. The principal dam- 

 age is done to the blossoms of the host. 

 Strawberries especially suffer from their 

 attacks. Accordin.g to Professor Quaint- 

 ance, the pistil is the portion of the blos- 

 som destroyed. The winter is probably 

 passed in the soil, as in the case of the 

 l)ear thrips iEitihripa pyri). 



Food Plants 



Strawberry, orange, rose, lilac, grass. 



Control 



This insect is seldom destructive 

 enough to warrant control. The sprays 

 used for pear thrips (except whitewash 1 

 are effective in controlling this pest. 



Ghkenhou.se Mealy Buc. See Citrms 

 Mealy Bug. this section. 



Greenhouse Thrips 



Heliothripn har^mnnhiiidiilis Bouche 



General Appearance 



The adult insect is characterized by 

 having the antennae eight-segmented and 

 twice as long as the head, while the sur- 

 face of the body is distinctly reticulated. 

 The abdomen is yellowish brown, with 

 head and thorax dark brown and an- 

 tennae, legs and wings colorless. 



Life History 



The very minute, bean-shaped, color- 

 less eggs are inserted in the leaf tissues 

 of the food plants, usually on the under- 

 side. They hatch in about ten days. Each 

 female lays from 10 to 20 eggs. 



Food Plants 



Citrus, azalea. Aspidium, crotons, dah- 

 lias, phlox, verbena, pink, ferns, vines, 

 cherry, laurel, laurestinus, palms, Ficus 

 sp., Pp.Uaca hastata, Liliacaeae, fuchsia. 



mango, begonia, cattleya, grape, Norfolk 

 Island pine, smilax. On citrus the fruit 

 as well as the foliage is scarred. 



Control 



S|)rays recommended for pear thrips 

 (Euthrips pyri) are also applicable for 

 this pest, but in spraying tender green- 

 house plants these should be weakened to 

 two-thirds normal strength. In spraying 

 for the greenhouse thrips on citrus trees, 

 use the formulae recommended for citrus 

 thrips (Euthrips citri). 



Fumigating may be employed if the 

 greenhouses can be made reasonably tight, 

 using one-third to one-half of an ounce 

 of potassium cyanide to every 100 cubic 

 feet of space, proceeding as directed for 

 orchard fumigation work. 



Natural Enemies 



Mites prey upon this species to a con- 

 siderable extent, but render little reliable 

 aid. 



Green Peach Aphid. See Peach Pests. 

 HEMispHEniCAL ScALE. See Peach Pests. 



Ivy Scale. See Apple Pests. 

 Japanese Wax Scale. See Okra Pests. 

 Long Scale. See Glover's Scale, this 

 section. 



Melon Aphis. See Aphids. 



Orange Cliionaspis 



Chiomispis citri Comst. 

 General Appearance 



The female scales are elongated, black- 

 ish-brown in color, with gray margins 

 and dark-yellow exuviae. The male scales 

 are very smali, long and narrow, white 

 with exuviae yellow. They are often 

 grouped so thickly as to almost hide the 

 females and make the branches appear 

 white. 



Life History 



Practically the same as that of C. 

 riioin/nii. 



Food Plants 



Its favorite food plant is the orange, 

 though other species of citrus trees are 

 attacked as well as holly, palm. 



Control 



Fumigation as for red or purple scales 

 will easily control this ]icst. 



E. O. E.SSIG 



