128 



PESTS OF CANE, MAIZE, AND SORGHUM. 



Fig. 149. 



Motli-l)orer Caterpillar, in hibernafinij eondHion. 



{Magnified three times.) 



The withered 

 '' deadheart ') . 

 killed in this 



takes about six weeks, one week for the egg-s, four weeks for the 

 caterpillar, one week for the chrysalis, and a couple of days for the moth 

 to lay eggs. 



In November the caterpillar often ceases feeding, and rests ; it does 

 not change to the chrysalis, 

 biit simply lies in its bur- 

 row hibernating. It may 

 remain in this state imtil the 

 end of May, when it turns 

 into a chrysalis and comes 

 out as a moth in June. It 

 may also come out and rest 

 as a moth before this time ; if there is irrigated cane or maize growing 

 during the cold weather or dry weather, the moth may emerge as it does 

 in the warm weather and never hibernate. This depends upon local 

 circumstances, though the rule is that the caterpillar hibernates during 

 the cold and dry weather, especially if it is in sorghum. 



The caterpillar is often very destructive to young cane, 

 leaves show that the caterpillar has killed the shoot 

 During the first five months many young cane shoots are 

 way, the plants thus becoming weak and sickly. When the cane becomes 

 larger, the caterpillar attacks the stem, boring into the growing canes. 

 If it can find other food, such as maize or sorghum, it will often leave the 



cane, but if only cane is 

 grown it may continue to 

 attack and damage the cane. 

 In sorghum, the caterpillar 

 attacks the young shoots just 

 as it does in cane ; it also 

 bores in the stems, being 

 usually very abundant as 

 the sorghum ripens. Where 

 there are many caterpillars and each stem contains several, the crops may 

 be seriously damaged. After the grain is harvested, the caterpillar 

 remains in the dry stems and especially in the stumps, which are left in 

 the field. ^ 



In maize the caterpillar lives in all parts of the plant, except 

 the roots. It bores in the stems, feeds upon the tassel and is 

 particularly fond of the cob. Many young caterpillars are often 

 found in the ripening maize, eating the grain so that the harm is 

 very apparent, 



Fig. 150. 



Moth-horer Caterpillar, in hihernating condition. 



{Maffnijled three times.) 



