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



granular form of calcium cyanide for 

 each 100 cubic feet of space. A temper- 

 ature of 60° to 70° F. should be main- 

 tained within the chamber during the 

 fumigation for best results. 



Caution. — Since this gas is a deadly 

 poison, the calcium cyanide should be 

 handled only by those thoroughly 

 familiar with its use. Where the 

 fumigation box is in a room, provision 

 should be made for adequate ventila- 

 tion. 



Should aphids appear on the foliage, 

 buds, or flowers, spray or dust them with 

 nicotine, pyrethrum. or derris, as recom- 

 mended for aphids on page 9. 



Prevention. — Examine all bulbs 

 carefully before they are placed in 

 storage; and if they are infested, use 

 either treatment recommended above. 



Green Peach Aphid 



The green peach aphid (p. 75) at 

 times attacks tulip and crocus bulbs 

 while in summer storage, causing damage 

 that results in weakened growth and 

 poor flowering. The aphids of this 

 species, and possibly others, also at- 

 tack the growing plants and may trans- 

 mit the virus of certain diseases from 

 infected to healthy plants. 



Treatment. — For bulbs in storage, 

 use the treatment for the tulip-bulb 

 aphid, discussed above. For aphids 

 on growing plants, see treatment for 

 aphids on page 9. 



Tulip Leaf Aphid 



The tulip leaf aphid (Rhopalosi- 

 phoninus tulipaella (Theo.)) feeds on the 

 foliage of both tulip and iris. The 

 aphids cluster on the leaves and shoots, 

 where they suck the sap. As a result 

 the leaves may fail to open or the plants 

 may be killed. This aphid winters 

 over on the dormant bulbs in the ground. 



Treatment. — Where the foliage is 

 infested, spray or dust with nicotine 

 sulfate, pyrethrum, or derris, as dis- 

 cussed under aphids (p. 9). Where 

 harvested bulbs are infested, use the 

 treatment recommended for the tulip- 

 bulb aphid (p. 87). 



Other Pests of Tulip 



Page 



Narcissus bulb fly 60 



Lesser bulb flies 54,61 



Bulb mite 61 



Red spiders ■ 11 



Wireworms 15 



Millipedes 17 



VERBENA 



Verbena Bud Moth 



The caterpillar of the verbena bud 

 moth (Endothenia hebesana (Walk.)) is 

 about Yz inch long, with a dull copper- 

 colored body and a black head. It has 

 many food plants, including verbena, 

 iris, snapdragon, gentian, tigerflower, 

 hedge nettle, mullein, and false fox- 

 glove. The caterpillars bore into the 

 flowers and feed on the contents of the 

 seed capsules (fig. 149). On iris, where 

 they are becoming of increasing im- 

 portance, the injury seems to be con- 

 fined to the seed pods. On verbena 

 they often web, tie together, and feed on 

 the flower heads. The insect over- 

 winters as larvae or pupae hidden in 

 the stems or seed pods of the plants. 

 The small, brown adult moths emerge 

 early the following spring. The species 

 is widely distributed. There are from 

 four to six generations annually. 



^m% 



Figure 149. — Seed pods of snapdragon 

 bored by caterpillars of the verbena 

 bud moth. Empty pupal skin pro- 

 truding from pod on right. Below, 

 caterpillars, or larvae; about twice 

 natural size. 



Treatment. — On the first sign of 

 injury the flowering buds and tender 

 growth should be sprayed or dusted with 

 lead arsenate and a second application 

 made a week later. Where only a few 

 caterpillars are present they may be 

 removed, or the infested parts picked off 

 and destroyed. 



Prevention. — Since the insect spends 

 the winter in the stems and seed pods 

 of its various host plants, it is essential 

 that all plant remains be gathered and 

 disposed of by burning, preferably late 

 in the fall. 



