The Colorado Beetle. 



The closely related tomato (Ly coper sicum), the thorn 

 apple (Datura)^ the henbane (Hyoscyamus), the tobacco- 

 plant (Nicotina), the apple of Peru (Nicandra), the ground 

 cherry (Phy satis), belladonna, and petunia have also been 

 recorded as harbouring this pest, but upon scarcely any 

 can it nourish except the tomato. 



Several specimens taken at Tilbury fed and matured on 

 the tomato. 



Various poppies, especially the Mexican or prickly 

 poppy [Argemone Mexicand\ also serve as food plants in 

 America. 



From the States it has also been recorded feeding on the 

 following : The pigweed (Amarantus retroflexus, L.), the 

 hedge mustard {Sisymbrium officinale), oats, smart-weed 

 (Polygomtm hydrosipei, L.), the red currant, various 

 thistles, goosefoot (Chenopodium hyhrtdum, L.), thorough- 

 wort (Ettpatorium perfoliatum, L.), the European black 

 henbane (Hyoscyamus ntger, L.), and the mullein ( Verbascum). 



Grasses and other weeds have been known to harbour 

 the larvae. At Tilbury they were observed feeding on 

 woody nightshade, cabbage, and thistles, whilst the eggs 

 were found in one case on the sowthistle (Sonchus). It 

 thus seems that although members of the genus Solanum 

 are its chief diet, especially the cultivated potato (where 

 its original food plant does not occur), both larvae and 

 adults can feed off a variety of other plants, preferably 

 devouring the young leaves. 



How the Pest Travels. 



The Colorado Beetle can only spread under natural 

 conditions in the adult or beetle stage. The beetle, with its 

 ample rose-coloured wings, is capable of considerable powers 

 of flight, but its enormously rapid advance in numbers in 

 America, sometimes at the rate of 100 miles a year, cannot be 

 attributed to its own locomotive powers, save under excep- 

 tional cases. That the beetles can keep alive a great time in 

 water is a factor which enables them to spread very rapidly ; 

 they may get drifted down stream a great many miles before 

 they would be destroyed ; similarly, they may fall into and get 

 drifted across large lakes. This potato pest may be found in 



