346 



THE AGRICULTURAL NEWS. 



OOTOBEK 26, 1912. 



INSECT NOTES. 



A SUGAR-CANE PEST IN ST. CROIX. 



Dr. Longfield Smith. Fh D., Director of Agiijullure, 

 St. Croix, Danish West Indies, in corrospnndence with the 

 Imperial Commissioner of Agriculture, ha.s given a brief 

 account of an insect which occurs in that island as a pist of 

 .-sugar-cane. 



The insect is a large, biown beetle the name of which 

 Dr. Smith gives as Sfrafegus titantis; it belongs to the same 

 family as the common hardback {Ligi/ms tid/iulosus). 

 The larva of Strategus titanas is in shape and general 

 appearance similar to the typical larvae of insects in this 

 group, but it is much larger than the common hardback 

 larva, attaining a length of over 2 inches, while it is about 

 .|-inch in thickness. 



The insects of this group, Dynastides, are more often 

 scavengers, feeding on decaying organic matter, than actual 

 pests feeding on the living tissues of plants of economic 

 importance. When however, they do occur as pests the 

 injury to plants is usually the result of the feeding of the 

 grubs on the fine roots after the manner of the related insects 

 of the Melolonthid group, of which the brown hardback 

 (Phi/talus sinithi) and the .\tay beetles {Lachnosterna ixUens' 

 in St. Vincent and L. jMtrnelis in St. Kitts) are examples. 

 In the case of the sugar-cane beetle {Ligiirua rugiceps) of the 

 United States, however, the injury is reported to be due to 

 the adults tunnelling into the base of the stem The 

 injury to canes in St. Croix by Strategus titanus is different 

 from both these. The habits of this in.sect are stated by Dr. 

 Smith to be as follows: 'It occurs very abundantly, much to 

 our disadvantage. It [the larva] eats the roots of canes, 

 sweet potatoes and other plants, and burrows into the basrs 

 of the cane shoots, eating its way upward, and turning the 

 cane into a hollow tube. The insect is saprophytic as well 

 as parasitic. I have found it living in decaying megass 

 heaps. At present (September 18) the grubs do not seem to 

 be so abundant as they were, probably because many have 

 turned to beetles, which are now busy laying eggs.' 



There would seem to be no doubt that Strategus titanus 

 is capable of becoming a very serious pest, and it is obvious 

 that every efi'ort should be made to prevent the introduction 

 of this insect into any colony where it does not at present 

 exist. 



A Coco-Dut Pest in the Philippines.— In the 



Philippine Agrictdtural Journal for ^larch last an article 

 appeared which gave an account of a new coco-nut pest in 

 those islands. 



This insect has been described as Alegrodicns destructor, 

 <.Juaintance. It is one of the white flies, closely related to 

 the white tly (A. cocois) of coco-nuts and other palms 

 in the West Indies, and although it differs from the 

 latter somewhat in the appearance of the adults and of the 

 masses of wax filaments among which, on the surface of the 

 leaf, the eggs, larvae and adults are to lie found, the nature 

 of the injury inflicted on the tree is the same in the case of 

 both species. It is probable therefore that the newly dis- 

 covered white fly may become as serious a pest in the coco- 

 <nut growing district? of the East as its relative has been in 

 the American tropics. 



THE CORN EAR WORM. 



The corn ear worm appears to be causing a very consid- 

 erable amount of damage in the Southern States, and it 

 would seem from a report of the Entomologist of tha 

 Trinidad Board of Agriculture, in .Inly last, that this insect 

 was also unusually abundant in Trinidad. 



Fii4. 13. TiiK Corn Ear Worm. 



a, UKith, plain t;ray fcrin; b, forewing of more ornamental 

 form; c, larva extendeil; rf, abdominal .segment of larva, lateral 

 view; i\ pupa, latf)-al view; d, twici- natural .size; others enlarged 

 one-fourth. 



(From I' S. Dept. Agric.) 



Dr. W. E. Hinds, in a letter to the Entomologist on 

 the Staff of the Imperial Department of Agriculture, states 

 that the boll vrorm (Heliothis ohsoleta) is usually the more 

 common worm attacking corn in Alabama, but that this year 

 (1912) the corn ear worm {Laphygma fvugiperda) is the 

 more abundant, and that it does not seem possible to main- 

 tain an efficient control over this insect, when it occurs ia 

 such enormous numbers in fields of Indian corn, even by the 

 use of such insecticides as arsenate of lead and Paris green. Ia 

 fact Dr. Hinds states that some of the farmers assert that 

 this insect is not killed by these poisons, even when it eats 

 them. In Trinidad, however, good results in its control oa 

 Indian corn are reported to have been obtained by the 

 use of arsenate of lead. 



It is of interest to note that the corn ear worm ia 

 usually much the more abundant of these two insects, in the 

 West Indies. Roth species attack corn generally, and cottoa 

 but rately. In the attacks on cotton, also, the corn ear worm 

 appears to occur more frequently than the boll worm in the 

 West Indies, and this also is in contrast to the conditions ia 

 the Southern States where the boll worm is in most seasons 

 a serious pest on cotton, and the corn ear worm is very 

 seldom recorded as a pest of this crop. 



A note in Dei- Tropi:npflat):i:r for August shows that 

 the production of camphor and camphor oil (to the nearest 

 1,000 lb.) in Formosa during 1911 was 5,200,000 and 

 7,467,000 B).; in 1910 it was 7,067,000 and 7,733,000 1b, 

 and in 1909. 4,667,000 and 5,067,000 R). Similarly the 

 output of these products in Japan, in the same order, was 

 for 1911, 1910 and 1909, 1,467,000 and 2,400,000 ft, 

 1,333,000 and 2,133,000 lb., and 1,067,000 and 1,467,000 »» 



