250 



THE AGRICULTURAL NEWS. 



-1 1 i.v 31, 1915. 



-■ 



INSECT NOTES. 



THE PINK BOLL WORM. 



(GELECHIA 



5YPIELLA, SAUK DEES. ) 



In. i recent number of the Agricultural News (page 186 

 of this volume) attention was directed to the pink '"'II worm 

 nt cotton as a pest which lias proved to I >♦ ■ most serious 



irer n has occurred, and which would in .ill probability 

 pi ivi to be equally serious if it should occur in the West 

 [ndies. Foi the sake of emphasizing the importance of this 

 insect is a cotton pest, tie present, more extended account 

 li i- been prepared. 



A circular issued by the United States Depart nt of 



Agriculture entitled The Pink Boll Worm has recently been 



received. This gives a g I account of the insect and of its 



origin, f 1 plants, distribution, etc., and since it presents in 



convenient form a summary of the essentia] facts, it has been 

 largely drawn on in the preparation of these notes. 



DISTEIBl TI'iV 



For several years the pink boll worm has been reported as 

 i ing cotton indifferent countries, [n L906,Maxwell Lefroy 

 published in his Indian Insect Ve>U the distribution of the 

 pink boll worm as known at that time: it was Inilia. Ceylon, 

 Burrnah, and the Straits Settlements. Three years later 

 (1909) Indian Insect Lift bj tlie same author appeared 



In this work the pink boll worm was rec rded I i East 



Africa in addition to the previous known localities. In the 

 Circular ol the U. S. Department of Agriculture mentioned 

 above, the distribution of this insect in 191-1 is given as 

 follows: 'The pink boll worm was described originally from 



Imli i in 1843. Since that time it has I n found more or 



less generally widely spread in [ndia, Ceylon, Burnwh, 

 Straits Settlements, Egypt. British East Africa, German East 



\ jreria, Sierra I ie, and the Hawaiian Islands In 



! Hawaiian Islands it was undoubtedly introduced in 

 cotton seed from India. There is also a doubtful record of 

 the i ui rencc of th< in J ipan 



linw THE INSEi r -I'M: '. .>-. 



The moth, which is the adult form of the pink boll worm, 

 is a small fragile insect which cannot il\ far. [f this were 

 ,;, nly way r>i even the ordinary way in which the insect 

 , i from place I i place, it would be able to disperse only 

 lowly. It is, however, in the immature tage that the 

 spread of the pink boll worm ean bo accomplished. The 

 larvae live inside the cotton seed in the growing bolls, in seed 

 in old dried bolls, and in ei d in bulk shippi d for planting or 



, iction. It will be seen t this that the shipment of 



I is the means by which the pink In. II worm is 



introduced into one country from another, and when it is 

 known that the records shon that in Egypt, in one in tarn e it 

 least, i pink boll worm (the caterpillar or worm it eli 

 lived foi seven months, it will he seen how great thedangeris. 



The pink In. 11 worm may also be transported in baled 

 cotton. Cotl into the ginned lint either by the 



seed passing around the end ol the rollers in the gin, oi 

 :. the roller and the knife; and in one 

 instance at least a living pink boll worm has been found in 

 otton seed insidi the bale of cotton when this has reached 

 its destination al h factory where the cotton was to 1"' 

 spun. 



in i: HISTORY. 



The 2 ; of the pink boll worm, which 



hatch in about i deposited singly on various parts 



of the cotton plant. The larvae, which are very small when 



first hatched, feed i liort time mi the leaf surface, but 



soon penetrate to the interior of the cotton Lolls. 



The larval stage lasts about twenty days, at the end 

 of which time the full-grown worm is about i-inch long, 

 and somewhat pinkish in colour. It is in the larval stage 

 that the insect injures the cotton by feeding upon the seeds. 



The pupa is often formed inside the hull Or shell of the seed 

 from which the larva, has eaten out all the interior, 



The pupa stage lasts about fourteen days,after which 

 the insect becomes a moth. The moth of the pink boll 

 worm is about \ inch in expanse, the colour being of 

 a general greyish, lu-own with darker blotches. In this 

 stage the insect lives ten day- or longer, probably longer as 



a rule. Egg-laying begins about thn r four days after 



the moth emergi 



The figures representing the length ol tin several stage 

 are then, as follows: — 



Total 



a I days 



As it is in the larval stage that injury is done to the 

 cotton and that the insect i- most likely to be introduced 

 into new localities, SO also is it that in the larval stage the 



greatest variation in duration occur-. As already mentioned, 

 it has been shown in Egypt that it is possible for the larva, 

 that is the pink boll worm its. -If, to live for seven months in 

 tin- cotton seed. This time is sufficient for the transportation 

 of cotton seed to the most remote part- ol tin world. 



]■ i PL \\ I v 



All varieties of cotton are attacked bj the pink boll 

 worm, from the highly specialized Sea Island types to the 

 hardiest oi native varieties in all countries where the peal 

 occurs. In the II iwaiian Islands this insect has been reared 



from Thespesia popu nea, which is know the West Indies 



as Mahoe or Anodyne. Iii Egypl it has attacked Til (prob- 

 ably Sesaiuum indicum), and p granates. 



The fact that plants differing in their nature so much as 



these -hold. I i e attacked, indicate- that once established the 



pink I". II worm would continue to subsist SO lone as plants 



with oily seeds, not too well protected from attack, occurred 

 even in the absence of cotton and other favoured f 1-. 



FNJI l:\ T I I OS 



The pink boll worm injure- cotton by causing a loss of 

 many bolls, and by spoiling much cotton in the hulls thai 

 remain on the plant. 



In case- of heavy infestation, fully ">u per cent, of 

 the crop may be lost by the dropping oi young bolls which 

 are injured l<\ I he feeding ol the c iterpillar. 



