THE SEMTTROPTCAL ARMY WOEM. 69 



Analj/fiis o/ }.5.;/ Misc. 



Per cent. 



Moisture 4. 85 



Total arsonioiis oxid 40.42 



Total copper oxid 24.87 



Gum aud dextrin (approximate) 20.00 



Acetlcacid and other uiuiclcrniined 9.86 



Total S- 100. 00 



Soluble arsenious oxid 11.36 



(10 (lay water ext. method.) 



From the above analysis the sample evidently consists of about 20 per cent 

 gum and dextrin and SO per cent Taris green. The amount of soluble arsenic is 

 very high and would undoubtedly give rise to serious trouble. 



SUMMARY. 



The semitropical army worm is a smooth or hairless noctuid 

 caterpilhir, Prodenia eridania Cram. It feeds normally on Aveeds, 

 such as the pokeweed and spin}- amaranth or '* careless weed "' of the 

 South, and is confined to semitropical America as a pest. "Wlien it 

 becomes unduly abundant it attacks the foliage and, in some cases, 

 the stems and fruits of all forms of garden truck growing in its 

 habitat, the list of known food plants including tomato, potato, sweet 

 potato, eggplant, pepper, okra, collards, and cowpeas. In its habits 

 it is similar to the cutworms, having also the climbing habit, and 

 when extremely abundant it migrates in armies like the common army 

 worm, wlience the name. 



Experiments show that the egg period may be passed in a min- 

 inunn of 4 days, the larval period in 17 days, and that the entire life 

 cA^cle, in an outdoor sunnner temperature, wotdd be about 35 days or 

 5 weeks; also, that there are four generations and possibly five pro- 

 duced in a year, the insect breeding practically continuotisly during 

 the warm season. Li ordinary 3'ears the species is largely controlled 

 by natural enemies, of which seven are parasitic and six predaceous. 



A series of fifteen experiments was conducted against this species 

 in Florida during 1907, which shows conclusively that a spray of 

 arsenate of lead is the best remedy, being much superior to Paris 

 green when applied under local conditions. It is in every way more 

 eifective, chiefly because less likely to be washed away by the frequent 

 rains of the wet season in that region. It is best applied at the rate 

 of "2 or 3 pounds in ."iO gallons of water, and applications must be 

 renewed when the insects again l)ecome numerous, as the latter are 

 apt to spread from unsprayed plants. 



