October, 1909.] 



319 



Plant Sanitation, 



open to ensure a supply of air. Infested 

 pods can be recognized by the presence 

 of this circular hole, visually situated 

 near the base. The fully grown cater- 

 pillar may either spin its cocoon amongst 

 the lint, or it may desert the boll 

 ami descend to the ground, where it 

 pupates amongst the loose earth. It 

 finally emerges as a small dull-coloured 

 grayish-brown moth with narrow wings, 

 having an expanse of from f to f of an 

 inch. Lefroy states that, in India, there 

 are six broods in the year, and that— 

 in the colder districts — the caterpillar 

 hibernates in the seed. Bolls tnat have 

 been attacked by the insect usually 

 open prematurely and do not ripen their 

 lint, which remains in a more or less 

 matted condition. The premature split- 

 ting of the bolls also makes way for the 

 entrance of cotton-stainers (described 

 below) which complete the mischief. 



2. The ' Hairy Boll-worm ' (Earias 

 fabia). This is a rather larger caterpillar, 

 very pale green, with some yellow spots 

 and darker markings on each side- The 

 hairs are sparsely scattered over the 

 body. It tunnels not only into the 

 young bolls but also into the tender 

 stems of the plant. Like the ' pink boll- 

 worm ' it may pupate either inside its 

 tunnel or on the surface of the ground. 

 The moth is a very pretty little insect ; 

 the front wings creamy white, with a 

 bright green wedge-shaped band extend- 

 ing through the middle of the wing from 

 the body to the outer margin. It is a 

 more thick-set moth than that of the 

 previous species, and has an expanse of 

 I of an inch. This species of boll- worm 

 has been recognized only recently in 

 Ceylon, but is a well known pest of 

 cotton in India where, according to 

 Lefroy, it has about eight broods in the 

 year. The resulting damage is similar 

 to that caused by the pink boll- 

 worm. 



For remedial treatment, these two 

 species may be considered together. The 

 collection and destruction of the wormy 

 bolls which — after a little practice — are 

 easily recognized by the presence of 

 the small circular entrance to the 

 tunnel, or by the premature splitting of 

 the pod, will greatly reduce the later 

 broods and so lessen damage to subse- 

 quent crops. But this will not save the 

 existing crop which has already been 

 damaged. The similarity of the mode of 

 attack to that of the Codliu moth of the 

 apple, suggests the possibility of a 

 similar preventive treatment, namely, 

 by spraying with Lead Arsenate as soon 

 as the fruit begins to swell. The young 

 caterpillars, in attempting to tunnel 

 into the boll, will be poisoned by the 

 superficial layer of arsenic. 



As already mentioned, Mr. Lefroy 

 records the hibernation of the pink boll- 

 worm in the cotton seed in the colder 

 parts of the plains of India. It is doubt- 

 ful if any hibernation would occur in the 

 warmer districts, or in Ceylon. And yet 

 it is difficult to account otherwise for 

 the sudden appearance of the pest in 

 newly-planted and isolated fields. Mr. 

 Lefroy informs me that— as a pre- 

 caution — he recommends the fumigation 

 of the seed before planting. Imported 

 cotton seed is now being fumigated at 

 Colombo before delivery ; but if hiber- 

 nation in the seed is of more genera- 

 occurrence, it would be equally advisl 

 able to fumigate local seed, or to dis- 

 infect it in some other manner. 



Next iu importance to the ' boll-worms 

 are the ' cotton-stainers.' These belong 

 to the bug tribe (the Hemiptera) and are 

 armed with sharp sucking proboscis. 

 The cotton-stainers earn their name 

 through the frequent discoloration of 

 the lint either from their excreta or by 

 the juices of their bodies when acci- 

 dentally crushed. The following four 

 species attack our cotton in Ceylon. 



3. The 'Dusky Cotton-Stainer ' (Oxy- 

 carenus Icetus). This is a very small 

 dingy little insect, scarcely more than 

 one-eighth of an inch in length ; the 

 body and legs dull black ; the wings 

 semi-transparent and folded close across 

 the back. This bug swarms in the 

 cotton bolls after they have opened, 

 and is, I believe, itself responsible for 

 the premature opening of many of the 

 bolls. It also punctures the green pods, 

 causing them to dry up and split. It 

 occurs in countless thousands in the cot- 

 ton fields. As many as a hundred indi- 

 viduals may occupy a single infested 

 boll. I have not seen the eggs, but Mr. 

 Lefory states that they are laid amongst 

 the lint, close to the seed, in batches 

 of six to ten. He describes the eggs as 

 cigar-shaped, about one-thirtieth of an 

 inch long, of a bright yellow colour at 

 first, but turning bright orange shortly 

 before hatching. The young insects are 

 miniature editions of the parent, but 

 lighter in colour and wingless. 



4. The ' Ceylonese Cotton-Stainer 

 (Oxycarenus lugubris) is very similar to 

 the preceding species, but may be dis- 

 tinguished by its black wings, each with 

 a creamy white triangular spot near its 

 base. The young insect is of a brick-red 

 colour, with a white band across the 

 base of the abdomen. It occurs only in 

 Ceylon. Its habits are similar to those 

 of its ' dusky ' relative. 



5. The 'Banded Cotton-Stainer ' (Dys- 

 derciis cingulatus). This is a larger in- 

 sect, more than half an inch long. The 

 general colour varies from grayish- 



