18 



BULLETIN 513^ U. S, DEPARTMENT OF AGRICULTURE. 



Table I. — Plants and insects fumigated tvith liydrocyanic-acid gas in green- 

 houses — Continued. 



Name of plant. 



Primula chinensis.. . 



Do 



Do 



Primula malacoides . 

 Primula obconica . . . 



Do 



Psidium guajava 



Do 



Rhododendron 



Rhyncospermum, sp . 



Rosemary 



Do 



Rose 



Do. 



Do 



Sage, scarlet.. . 



Do 



Do 



ScMzanthus sp . 



Do 



Scilla nutans. . . 

 Smilax 



Do 



Snapdragon... 



Do 



Spiraea cantoniensis.. . . 



Spiraea latifolia 



Spiraea thunbergii 



Spiraea vanJiouttei 



Spiraea sp 



Stephanandra flexuosa. 

 StenJianotis floribunda. 



Stevia sp 



Stocks 



Sweet peas 



Thunhergia erecta . 



Do 



Tulip 



Verbena 



Do 



Verbena (lemon) . 



Vinca major variegata.. 



Do 



Do 



Vinca rosea 



Do 



Wandering Jew 



Yucca 



Rate in 



ounces 



per 1,000 



cubic 



feet. 



.5 "a 



p-l 



5* 



60 



Infestation. 



Greenhouse 

 white fly. 



Long scale . 



Rose leafhop- 

 per. 



Aphids. 



do., 



do.. 



do.. 



Aphids. 



Aphids . 



Results of treatment. 



On plants. 



No burning... 



....do 



....do 



....do 



....do 



....do 



....do 



do 



....do 



....do 



do 



do 



Tender growth 



biuned. 

 ....do 



do 



No burning 



do 



do 



do 



do 



do 



do 



Severe burning. 



Tender tips 



burned. 

 do 



No burning . . . 



do 



do 



do 



do 



do 



do 



do 



do 



Tips and blos- 

 soms burned. 



No burning . . . 



do 



do 



do 



do 



Tender growth 

 burned. 



No burning . . . 



do 



do 



do 



do 



Severebuming 



No burning . . . 



On insects. 



All stages except eggs 

 and late pupae killed. 



Immature stages kiUed. 



100 per cent killed. 



Do. 

 Do. 

 Do. 

 Do. 



Do. 



Do. 



PLANTS AND INSECTS FUMIGATED IN FUMIGATION BOX. 



To determine the susceptibility of the plants listed in Table II, 

 these plants were fumigated in an air-tight box under favorable con- 

 ditions. Not only were they fumigated in an inclosure much tighter 

 than a greenhouse, but they also received dosages much in excess of 

 those commonly used in greenhouse work. 



