46 



MISC. PUBLICATION 62 6, U. S. DEPT. OF AGRICULTURE 



or field plantings, spray when the first 

 sign of injury appears. Spray with a 

 solution made up of 1 ounce (6M> level 

 teaspoonfuls) of tartar emetic, 2 ounces 

 {Yi cup) of brown sugar, and 3 gallons of 

 water. Repeat the application weekly 

 until flowering begins. Apply the spray 

 as a fine mist and repeat if heavy rains 

 occur within 12 to 24 hours after the 

 application. If it is necessary to con- 

 tinue spraying during the flowering 

 period, all spikes showing color should 

 be cut for use before each application. If 

 tartar emetic is not available, the paris 

 green formula (p. 96) may be used. 



Prevention. — Plant only thrips-free 

 corms. At harvesttime avoid shaking 

 thrips-infested tops over the corms. The 

 corms should be removed from the 

 garden as soon as possible to prevent 

 thrips from reaching them. 



Note: Several other species of thrips 

 may often attack gladiolus along with 

 the gladiolus thrips, but the spraying 

 program outlined above will control 

 these also. 



Grape Mcalybus 



Gladiolus corms are often attacked, 

 especially while in storage, by the 

 grape mealybug (Pseudococcus mariti- 

 mus (Ehrh.)). These insects cluster 

 around tender shoots and root buds, 

 where they suck the plant juices. This 

 results in a weakening and stunting of 

 the subsequent growth. When the 

 corms are heavily infested they are 

 literally covered with these insects. 

 This mealybug is similar in habits and 

 appearance to the citrus mealybug 

 (p. 31), except that it does not have the 

 body so heavily coated with the white 

 waxy or mealy covering. It feeds on a 

 wide range of food plants in addition to 

 gladiolus. These include, among others, 

 California poppy, columbine, carnation, 

 grevillea, English ivy, Japanese quince, 

 Japanese yew, palm, and poinsettia. 



Treatment. — For bulbs, same as 

 recommended for the control of root 

 aphids on tulip bulbs (p. 87). On 

 growing plants use the remedies given 

 for mealybugs (p. 31). 



Other Pests of Gladiolus 



Page 



Red spiders 11 



Corn earworm 29 



Yellow woolly bear 3 



Blister beetles 7 



Asiatic garden beetle 21 



Tarnished plant bug 35 



Stalk borer 34 



European corn borer 36 



Flea beetles 8 



Aphids _ 9 



Tulip-bulb aphid 87 



Bulb mite... 61 



GOLDENGLOW 

 Goldenslow Aphid 



Goldenglow, or rudbeckia, is often at- 

 tacked by the goldenglow aphid (Macro- 

 siphum rudbeckiae (Fitch)), a large, 

 shining, red or dark-brown plant louse. 

 The aphids gather in large colonies on 

 the tender shoots, leaves, and flowers 

 and cause injury similar to that done by 

 other plant lice. Chrysanthemum, let- 

 tuce, goldenrod, ragweed, sunflower, and 

 Fuller's teasel are among the other 

 plants which it attacks. 



Treatment. — Same as for aphids 

 (p. 9). 



Other Pests of Goldenglow 



Page 



Asiatic garden beetle 21 



Stalk borer 34 



Tarnished plant bug 35 



Four-lined plant bug . 91 



Fuller's rose beetle 44 



Red spiders 11 



HAWTHORN 

 Thorn-Leaf Aphid 



The thorn-leaf aphid (Anuraphis 

 crataegifoliae (Fitch)) attacks the young 

 leaves of hawthorn early in the spring. 

 The sucking of the plant juices causes 

 the young leaves to curl and the older 

 leaves to become crinkled. This aphid is 

 usually pinkish or yellowish green. 

 Many of the winged forms migrate to 

 clover and similar plants about mid- 

 summer. They return to hawthorn in 

 the fall to deposit the overwintering 

 eggs. Several other species of aphids 

 may at times also infest hawthorn. 



Treatment. — See treatment under 

 Aphids (p. 9). To protect the young 

 foliage, control measures should be ap- 

 plied about the time the new leaves 

 start growing. 



Hawthorn lacebugs 



Several species of lacebugs belonging 

 to the genus Corythucha commonly at- 

 tack the foliage of hawthorn. These 

 very small sucking insects feed on the 

 under sides of the leaves, where they 

 deposit small spots of dark excrement. 

 When numerous they cause the badly 

 infested foliage to become discolored and 

 fall prematurely. These lacebugs re- 

 semble the chrysanthemum lacebug 

 (p. 28) in appearance. 



Treatment. — Same as for the chrys- 

 anthemum lacebug (p. 28). 



