1956 



ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 



The larv^ are decidedly flattened, more 

 or less oval, with lateral spines or pro- 

 cesses from the margins, and at the end 

 of the hody is a fork which, in some 

 species, holds all the excrement voided 

 during life, and sometimes the cast skins 

 as well, often making a mass nearly as 

 large as the larva itself. 



Bemedial Measures 



The same measures suggested for pois- 

 oning the flea beetle will answer for these 

 tortoise beetles as well. Dip the plants 

 before they are set out in a mixture of 

 one pound arsenate of lead in from six 

 to ten gallons of water, to kill off the 

 adult beetles as soon as they begin to 

 feed. In the forcing bed, plants can be 

 sprayed with the weaker mixture with 

 good efEect because, as the insects eat the 

 entire leaf tissue, they will be poisoned 

 whether they eat from the upper or under 

 side. So, in the field, should the "ped- 

 dlers" become numerous enough to be 

 harmful, spraying may be resorted to 

 with good effect, as these also eat the 

 entire leaf tissue. 



Sweet Potato Plea Beetle 



Ghaetocnema confinis Lee. 



This is a small, bronzed, or brassy- 

 brown shining beetle, about one-sixteenth 

 of an inch in length, very active, some- 

 what chunky, with deeply ridged or stri- 

 ated wing covers. AIL these characters, 

 except the general shape and bronze color, 

 requiring a magnifying glass to make out 

 clearly. 



These beetles live through the winter 

 in rubbish, under logs, stones or among 

 masses of leaves and other vegetation. 



Early in May, when the weather be- 

 comes really warm, •'these beetles leave 

 their winter quarters and seek food. 

 Their eating is peculiar in character and 

 easily recognized. On either upper or 

 under side they chew out narrow grooves 

 or channels, at first close to and parallel 

 with some of the principal -veins; later, 

 when the leaf has been pretty well eaten 

 into, the channels may run any way. 

 Early in June the beetles begin to de- 

 crease in number, and, as the bindweeds 



are by this time growing vigorously, the 

 tendency on their part is to forsake the 

 cultivated for the wild plants. 



Bemedial Measures 



These may be direct or indirect, and 

 may consist of applications of an arsenic- 

 al poison, or a modification of cultural 

 methods. The simplest plan is to dip 

 the plants, before setting, into a mixture 

 of one pound arsenate of lead in ten gal- 

 lons of water. Use a good grade arsenate 

 of lead, running 14 per cent or more of 

 arsenic, or if a 12 per cent material is 

 used, make it one pound in six gallons 

 of water. Spraying will not answer the 

 same purpose as dipping, because it is 

 simply impossible to coat the leaves on 

 both sides as thoroughly. But in the 

 forcing bed the plants may be sprayed to 

 good advantage should the insects at any 

 time become sufficiently abundant to 

 make it desirable. 



The second method consists in delaying 

 the setting until the latest possible mo- 

 ment, so that the beetles may be forced 

 to the bindweeds and other natural food- 

 plants before the sweet potato plants get 

 into the field. 



Sweet Potato Stem Borer 



Omvfiisa anastomosaUs Guen. 

 Fbedeeick Maskew 



The sweet potato stem borer is Oriental 

 in origin, having been recorded as being 

 more or less general throughout the Indo- 

 Malayan region. So far it has not yet 

 become established in this country. 



There is but little hope of relief from 

 the application of remedies in localities 

 where this pest has become established. 

 During the most vulnerable stage it 

 works in secret, protected from interfer- 

 ence by the tissues of the plant it has 

 attacked. Those who by reason of ex- 

 perience in dealing with this pest are 

 the most competent to advise, offer as 

 the only practical course to pursue, a 

 complete change of location. The work 

 upon the mature potatoes is very insid- 

 ious and not to be detected until tht^ 

 potatoes are cut open. 



