August, 1909. J 



137 



Pla n t Sa nita Hon , 



Mr. Maxwell Lefroy (Entomologist to 

 the Government of India) informs me 

 that, in India, the larvae of the 1 Pink 

 Bolhvorm' hibernate in the cotton seed. 

 To guard against the recurrence of 

 the pest, the cotton seed is always 

 fumigated before being sown. This 

 habit of the bollworm may possibly 

 account for its sudden appearance 

 in the very first crop of cotton 

 grown on the Experiment Station 

 at Peradeniya, though it is difficult to 

 understand how it could have occurred 

 in such overwhelming numbers that 

 practically every pod of the first crop 

 was infested. There is no doubt that 

 other cotton pests are liable to be in- 

 troduced with imported seed, on which 

 account I have recommended to Govern- 

 ment the compulsory fumigation of all 

 imported cotton seed. 



Another bollworm, which is common 

 both in India and in Egypt, is the 

 caterpillar of the moth Earias insulana. 

 Though this moth occurs in Ceylon, it 

 has not hitherto been noticed here as a 

 cotton pest. But a single example of 

 what I believe to be this caterpillar was 

 recently found in a cotton boll on the 

 Peradeniya Experiment Station. Owing 

 to an injury during its extraction from 

 the boll, it failed to complete its trans- 

 formations, so I am unable to ddtermine 

 the specie? with certainty. 



The Vermorel acetylene lamp was 

 placed in position in the cotton plots for 

 one night, to see if the moths of the 

 ' pink bollworm ' (Gelechia gossypiella) 

 could be attracted to the light and 

 destroyed. But, though vast numbers 

 of other and harmless insects were 

 captured, not a single specimen of the 

 Gelechia could be recognized amongst 

 the victims. 



The Camphor plants on the Experiment 

 Station have been partially defoliated 

 by a species of 'bag-worm' (Clania 

 variegata). 



In a Report on "Rubber in Nyassalaud" 

 (from the Government Handbook, 1st 

 issue, 1909), mention is made of injury to 

 Para rubber plants by cockchafer grub. 

 " To get rid of the latter pest a mixture 

 consisting of one pound of Paris green 

 and three pounds of salt to 40 pounds of 

 donkey manure was used and proved 

 effectual, when dibbled in some little 

 distance from the roots at the time of 

 planting." This is the poisoned bait 

 used against locusts in Africa. It might 

 be tried (with the substitution of horse 

 for donkey manure), under similar circum- 

 stances, on our rubber clearings in Ceylon. 



The stems of a common climbing bean— 

 in frequent use as a native vegetable- 

 are sometimes attacked by the grubs of 

 » large black beetle with enormously 

 IS 



thicicenod, hind legs (Sagra sp.). The 

 presence of these grubs causes con- 

 spicuous tumour-like swellings on the 

 stems. As many as fifteen of these 

 white grubs have been found feeding 

 within one of these swellings. It is 

 astonishing that the plant shows such 

 little sign of inconvenience from the 

 presence of so many and such large 

 insects. 



In a recent number of ' Nature ' (May 

 13, 1909) is a letter describing a method 

 of killing house-flies by exposing dishes 

 containing formaldehyde (in the propor- 

 tion of two teaspoonfuls of the chemical 

 to a soup-plate full of water). The flies 

 are said to drink this mixture with 

 rapidly fatal results. 



MISCELLANEA. : CHIEFLY PATHO- 

 LOGICAL. 



By T. Pbtch. 



The death of tea and other seedlings 

 iu the nursery frequently results in 

 serious loss, not so much from the value 

 of the plants as from the delay it causes 

 in the establishment of new fields As 

 a rule the seedlings die out in patches, 

 but sometimes whole beds are destroyed. 

 In many instances this is due to eel- 

 worms, and the cause can then be readily 

 ascertained by examining the root, which 

 in such cases is distorted and tuberous. 

 When the plants are attacked by fungi, 

 the stem usually turns black at the 

 base, and the leaves fall off, but the 

 root is not swollen. It was pointed out 

 at the Rubber Exhibition of 1908, that 

 the health of nursery plants depended 

 chiefly on the care expended over the 

 selection and preparation of the nursery. 

 It often happens that, owing to diffi- 

 culties with regard to water supply or 

 the lay of the land, the same ground is 

 used for nurseries continuously. It is 

 quite true that the same patchcanbe used 

 repeatedly as a nursery, but in that 

 case it must be thoroughly worked be- 

 tween the sowings and preferably should 

 bear a crop of some other plant before 

 being used as a nursery again, Where 

 the seedlings have been destroyed by 

 any disease, it is useless to expect a 

 subsequent healthy growth on the same 

 ground without thorough and repeated 

 working of the soil and the application 

 of some method of disinfection. If pos- 

 sible, the site of the nursery should be 

 changed. 



In the case of tea seedlings, their death, 

 when due to fungi, is usually attributed 

 to Pythium, but this cannot be said to 

 have been definitely established, and 

 further investigation is necessary. An 

 instance of the death of Albizzia seed- 



