9 



Spraying the plants with arsenate of lead or Paris green 

 would be likely to destroy many of the insects when starting 

 new mines. In some parts of the United States it is the prac- 

 tice to send labourers through the fields to crush the larvae in- 

 side the leaf tissue, but this is probably only done where the 

 leaves are used as cigar wrappers. 



' WIREWOEMS."- The insects which go under this name 

 in Southern Khodesia are not true wireworms as the word is 

 usually applied. The destructive wireworms of Europe and 

 America are the grubs of " click " beetles or " skipjacks," be- 

 longing to the family Elateridce. The grubs injurious to 

 tobacco in this territory are the young of a family of soberly 

 coloured beetles of the family T ' enebrionidte , which includes the 

 " tok-tokje " beetles amongst others. These grubs have not 

 yet been bred out to the adult stage, but there are probably 

 several species involved. The grubs are of a slightly flattened 

 sub-cylindrical form, light yellowish brown in colour, and may 

 reach a length of two and three-quarter inches. They are 

 ;armed with a formidable pair of jaws, with which they are able 

 to sever tobacco stems of some thickness, thus destroying the 

 plant. They are usually brought to light when the wilted 

 plant is noticed and dug up. They attack the plants as soon as 

 the field is planted, but are also reported to kill healthy plants 

 In full growth. 



The probability is that the eggs are laid in the natural veld, 

 and that the insects attack tobacco because it happens to be the 

 plant within their reach, and not because they have any natural 

 preference for it, but that they thrive upon the diet is shewn 

 by the fact that land is often found to be infested the second 

 year as well as the first. Probably the insect takes more than 

 one vear to mat u re- 

 in rare cases the injury to tobacco by this pest may be 

 severe, the crop being rendered altogether unprofitable. Usu- 

 ally, however, the insect is present in but small numbers, and 

 the percentage of plants destroyed is quite inconsiderable. 



So little is known about these insects, that it is not possible 

 to recommend remedial measures. It is probable, however, 

 that when other crops come to be grown in rotation with 

 tobacco, injury by these insects may become a thing of the 

 past. With the present system of growing tobacco for two 

 years on one piece of land , and then allowing it to lie fallow for 



