Plant Sanitation. 



222 



[September, 1910. 



have all disappeared; apparently quite 

 independently of the borer. The bark 

 of the tap root was still in a healthy 

 condition. 



But whether the borer is or is not 

 responsible for the death of the trde, it 

 is distinctly a dangerous pest, and should 

 be treated as sucn. The difficulty with 

 these root borers is, that their presence 

 cannot be detected until the mischief 

 has been accomplished. The only practi- 

 cable means of checking the increase of 

 the pest is to collect and destroy the 

 adult beetles. We may expect to find 

 these resting upon the stems of the 

 trees when they come to lay their 

 eggs. Any large beetle with elongated 

 jointed horns, that may be found loiter- 

 ing on the premises, should be looked 

 upon with suspicion. The particular 

 species that is responsible for this 

 damage is nob yet known ; but the 

 accompanying figure (2) will give an idea 

 of what should be expected. 



Mealy Bug on Cotton Plants. 

 The improved Upland Cotton, on the 

 Cotton Experiment Station at Maha 

 Iluppalama, has been virulently attacked 

 by a 'mealy-bug ' {Dactylopiusvirgatus). 

 It increases with extraordinary rapidity 

 and appears to kill back the branches 

 upon which it congregates. This is a 

 pest that should receive attention at its 

 earliest appearance. When it has be- 

 come widespread it is difficult to check. 

 It is distributed by the coolies working 

 in the fields, the young insects attaching 

 themselves to the labourers' clothing. 

 Soapy insecticides are the best for 

 mealy-bug, 



Nettle Grub on Tea. 



An outbreak of ' nettle-grub' has been 

 reported from the Rattota district. The 

 species is Natada nararia. The Superin- 

 tendent writes that it " was first noticed 

 in June last, when it confined itself 

 to one portion of one field. That 

 portion which was first attacked is now 

 free from it and the bushes are in leaf 

 again. But in another part of the same 

 field the caterpillars are in full force. 

 They first attack the large coarse leaves 

 at the bottom of the bush and gradually 

 make their way upwards till they reach 

 the young flush ; but they play most 

 havoc with the old leaves." 



Arsenical sprays are the proper 

 treatment for leaf-eating caterpillars ; 

 but they are considerd dangerous in 

 connection with tea. Mr. Lef'roy credits 

 the Indian insecticide ' Vermisapon' with 

 the property of killing small caterpillars. 

 It might be tried against nettle grub. 

 As an accessory measure, the fallen 

 leaves and rubbish from below the 



bushes .should be swept up and burnt. 

 This particular caterpillar frequently 

 pupates in such material. Cocoons will 

 also be found in the angles of the 

 branches. By destroying as many of the 

 cocoons as possible, a repetition of 

 the attack may be to a large extent 

 prevented. Dusting with lime or sulphur 

 has no appreciable effect upon these 

 caterpillars and is pure waste of time 

 and money. 



Another Scale-Bug Pest op 

 Castilloa. 



In " The Planters' Chronicle," (Vol. V., 

 No. 29, August 6), Mr. Anstead reports 

 that Lecanium olece is attacking 

 Castilloa trees in Southern India. It is 

 also found on Erythrina lithosperma 

 (Dadap), and is said to be rapidly spread- 

 ing on Coffee. This species is scarce in 

 Ceylon, and has never ranked as a pest 

 with us. 



Poisoned Bait for Fruit-Flies. 

 I have had frequent complaints of 

 injury to orange fruit by small maggots. 

 Mangoes and several other fruits, and 

 marrows, cucumbers and pumpkins are 

 subject to a similar pest. These maggots 

 are the laiva3 of several species of 

 ' fruit-fly ' belonging to the genus Dacus. 

 It is very annoying to find a promising 

 crop of fruit ruined by these little pests. 



Recent experiments in South Africa 

 have proved the efficacy of poisoned 

 baits in checking these flies. A note in 

 the "Natal Agricultural Journal" (July, 

 1910, p. 84), by the Government Ento- 

 mologist, reports that " Fruit-fly is being 

 successfully controlled by the appli- 

 cation of « Mally's bait.' " The bait in 

 question consists of syrup and Arsenate 

 of Lead which is sprayed or syringed on 

 to the foliage of the trees when the fruit 

 is commencing to ripen. The formula 

 is :— Sugar 3 lbs., Arsenate of Lead 4 oz., 

 and water 5 gallons. 



A somewhat similar mixture has been 

 employed in Italy to combax the Olive 

 fly. In this case the bait consisted of 

 Molasses 65 parts, Honey 31 parts, 

 Glycerine 2 parts, and Arsenate of Soda 

 2 parts. The flies are apparently very 

 found of sweets, and take their refresh- 

 ment before they transact their business. 



The Mango Weevil. 



The Mango Weevil (Cryptorhynchus 

 mangiferce) appears to be unusually 

 prevalent this season, The natives say 

 that there is one in every mango stone. 

 But the presence of the insect does not 

 seem to affect either the size or flavour 

 of the fiuit. The larva feeds only on 

 the kernel of the stone, and the beetle 



