The Tobacco Biidworm. 5 



Abbot * wrote as follows : " [This species] eats the bud and blossoms 

 of Rhexia, as well as of tobacco ; to the latter it is very pernicious in 

 Virfjinia and other places, as it destroys the main shoot." 



In Georgia in 1886 it was reported by a planter to have been more 

 injurious to tobacco than the hornworms.^ 



SEASONAL HISTORY. 



Eggs and larvae are present in tobacco fields in Florida and 

 Georgia throughout the growing season. Moths often appear early 

 enough in the spring to infest seed beds, and by setting-out time 

 eggs are being deposited in large numbers. From the end of the 

 growing season until the middle of August, larvae are abundant 

 upon stalks and suckers left standing in the fields. From this 

 time on their numbers decline very rapidly, although they have 

 been observed as late as November 23 at Quincy, Fla. 



Eggs are deposited singly on the leaves, usually on the under- 

 side. In Florida, during the growing season of tobacco, they hatch 

 in from three to five days. Newly hatched larvae first feed sparingly 

 on the shells of eggs from which they have issued and then eat small 

 areas about the size of a pinhead from the leaf surface. These 

 minute budworms then begin a migration and reach the bud of the 

 plant in about 2'4 hours. They often stop to feed two or three 

 times, but eat only one or two layers of the leaf cells and do no ap- 

 preciable injury until they reach the bud. 



AVhen the bud is reached the characteristic injury is wrought. The 

 young budworms conceal themselves between the immature, unfold- 

 ing leaves and begin to feed very greedily. They are so small and so 

 well concealed that they can be detected only by the very closest 

 scrutiny, and if a dose of poison mixture has not been placed in the 

 bud before their arrival extensive injury will have been done before 

 any remedial measure can be made effective. 



The larva or worm stage has been found to cover a period of from 

 18 to 31 days during May and June, at the end of which the mature 

 larvae burrow into the soil and pupate. The length of the pupa stage 

 may vary during the summer, covering a period of from 13 to 21 

 days. The emergence of adults from the ground is affected materi- 

 ally by moisture conditions, for it has been observed that a great 

 many moths often appear at the expiration of a dry period. 



After the moths emerge a period of from four to five days may 

 elapse before egg laying begins. Moths kept in captivity laid an 

 average of 334 eggs. From observations during May and June of 

 1916 the average duration of the life cycle was determined to be 

 37^ days. 



FOOD PLANTS. 



Besides feeding on tobacco, the budworm has been recorded in the 

 United States as attacking okra, deer grass,'"' geranium, and agera- 

 tum. It has been reported as feeding upon wild solanaceous plants, 

 including ground cherry' and another species of the same genus. 



* Smith. Sir James Edward. The Natural History of the Rarer Lepidopterous Insects 

 of Georgia. 1797. 



^ Protbparoe scjcta Joh. and P. quinquemaoulata Haw. 



* Rhexia viryinica. 

 '' PhysaJtis vinoosa. 



15667°— 23 2 



