158 MASS. EXPERIMENT STATION BULLETIN 206. 



Insects. 

 The Green Spanworm (Cymatophora sulphurea (Pack.)). 



This species was unusually prevalent in 1920, the moths appearing 

 abundantly on many bogs and the worms wiping out a fine crop promise 

 on several bogs in Duxbury. 



The moths were flying in clouds on the Duxbury bog on July 22 and also 

 on August 2. On the former date the males outnumbered the females 

 fully 200 to 1, while on the latter they seemed only slightly more numer- 

 ous. This indicates that the species is strongly protandrous in emerging 

 from the pupa. The males are more active than the females, but both 

 sexes rest much among the vines. The males fly much less than those of 

 Epelis truncataria, but they are flushed up easily. Several females reared 

 in confinement and dissected before they oviposited contained from 103 to 

 117 eggs. The greater egg capacity of Epelis^ may explain its greater 

 prevalence. Green span worms captured August 2 were found to be mostly 

 through lajdng. The greenish-white eggs are laid singly on the old fallen 

 leaves under the vines, and winter under the water (if the bog is flooded) , 

 hatching in the spring. 



The injury done on the Duxbury bog was much like the work of the 

 blossom worm - (or bud worm), the flowers being nipped off and dropped. 



The Broum Spamvorm {Epelis truncataria vaT.Jaxonii Minot). 



This species was found in great numbers on twelve different bogs in 

 1919, and the moths appeared abundantly on even more in 1920. It was 

 so much more prevalent than usual that it demanded as much attention 

 as any cranberry pest except the gypsy moth. The writer attended to 

 many requests for advice in checking infestations in 1920, and the insect 

 did little harm except on a few neglected bogs, lead arsenate (3 pounds of 

 powder to 50 gallons of water) being very effective wherever used. 



The worms began hatching June 30, 1919, and July 1, 1920, probably 

 being about normal in this respect both years. In 1919 they worked on 

 some bogs until into August. Uncounted hundreds over a thousand of 

 the small worms to 50 sweeps of an insect net were obtained on parts of one 

 bog two days after hatching began there. This bog was sprayed with lead 

 arsenate at once. It was examined again sixteen days later and 75 nearly 

 mature worms to 50 sweeps of the net were obtained on the area most in- 

 fested. These caterpillars were doing little harm, for the only notable 

 injury on the vines was the work of the multitude of small worms that 

 had been checked by the spraying soon after they began. The tips of the 

 \anes had made much new growth after the spraying. This was lighter 

 green than the earlier growth of the season and showed little worm-eating. 

 This and other observations have shown that an infestation of this insect 

 giving less than 50 worms to 50 sweeps of the net will not do much harm 



1 Mass. Agr. Expt. Sta., Bui. No. 150, 1914, p. 50. 



2 U. S. Dept. Agr., Farmers' Bui. No. 860, 1917, p. 23. 



