EBRUARY, 1910.] 



121 



Plant Sanitation! 



to 1,000 pounds of dry rubber per acre, 

 which is good enough for most rubber 

 planters. 



I have recently found examples of the 

 1 Shot-hole Borer ' (Xyleborus jornicatus) 

 in cankered branches of Hevea rubber. 

 The pest was prevalent in the surround- 

 ing tea and had found a suitable nidus 

 in the diseased rubber branches in which 

 there was no latex. This occurrence 

 need cause no alarm. A healthy rubber 

 tree is amply protected from boring 

 insects. In this particular case, it was 

 interesting to observe that several of 

 the beetles, having ventured upon 

 operations too close to the healthy area, 

 had been entrapped in the consequent 

 flow of latex. 



Another extremely interesting occur- 

 rence was the discovery of numerous 

 minute Staphylinid beetles in the 

 galleries of the borer. These beetles are 

 known to be carnivorous and predatory. 

 The presumption is that they were prey- 

 ing upon the defenceless grubs of the 

 borer. This discovery was considered of 

 such importance that a special visit was 

 made to the estate to ascertain whether 

 the friendly Staphylinids were fre- 

 quenting the galleries of the borer in 

 the neighbouring tea. But in this hope 

 I was disappointed. Still, the fact of 

 their association with the borer even in 

 the limited area of a diseased rubber 

 branch is encouraging. Having dis- 

 covered the edible properties of the 

 larvse in one situation, they may pos- 

 sibly extend their range. 



The leaves and young stems of Hevea 

 rubber are very frequently infested by 

 ' Black Bug ' (Lecanium nigrum). The 

 older trees do not appear to suffer from 

 the pest — to any great extent ; but when 

 the insect occurs thickly on small plants, 

 it checks their growth. Such plants 

 should be washed with MacDougall's 

 Solution. The older scales may first be 

 crushed by hand. 



'Brown Borer' (Arbela quadrinotata) 

 has been observed on Para rubber; in 

 the Ruanwella district. lu this instance, 

 it bad evidently strayed from the 

 Albizzia trees growing amongst the 

 rubber. The borer makes its entrance 

 at the angle of a branch or in the fork 

 between two stems. When observed, 

 the hole should be plugged with tow 

 soaked in coal tar. I do not think that 

 there is much likelihood of serious 

 trouble from this pest. 



I have received, from the Passara 

 district, a branch of Hevea from which 

 were suspended numerous cases of the 

 ' Bag-worm ' (Psyche vitrea). Tiiis insect 

 occurs commonly upon the tea, and it is 

 16 



probable that these individuals had 

 ascended the rubber tree solely for the 

 purpose of pupation. There were no 

 signs of defoliation of the rubber. 



'Kikxia' (Funtumia elastica) trees, 

 on the Experiment Station, have been 

 completely defoliated by caterpillai's of 

 thePyralid moth (Caprinia conchylalis). 

 This pest constantly^occurs in the months 

 of December and January, and has re- 

 sisted all attempts at treatment. At 

 the commencement of the present attack, 

 the trees were thoroughly sprayed with 

 Lead Arsenate, but without any bene- 

 ficial result. The caterpillar appears 

 to be restricted to a very limited range 

 of food-plants and is consequently un- 

 likely to become a general pest. The 

 only plant— other than Funtumia — upon 

 which I have seen it feeding is Port- 

 landia grandiflora (a shrub imported 

 from Jamaica), It must, however, have 

 some native food-plant, as the insect 

 occurs only in the Indian region. It 

 refuses to feed (even under pressure of 

 starvation) upon the leaves of either 

 Hevea or tea. 



The caterpillars of Lymantria Ampla 

 and Psyche albipes have been found 

 feeding upon the foliage of Manihot 

 dichotoma. The females of both these 

 moths are wingless and lay their eggs 

 in a mass in one spot. The resulting 

 larvse would naturally spread them- 

 selves over the plant upon which the 

 eggs had been deposited, and might 

 occasion serious defoliation. The ad- 

 vantage of destroying the original 

 caterpillars is obvious. 



I have received, through Messrs. Freu- 

 denberg & Co., specimens of a scale-insect 

 that is reported to be destructive to 

 Coconut Palms in the South Sea Islands. 

 I at first believed it to be a new and un- 

 described species, but 1 now find that 

 it has quite recently been described by 

 Dr. Lindinger, of Hamburg, under the 

 name of Furcaspis oceanica. It covers 

 the surface of the palm fronds with a 

 mass of small circular reddish-brown 

 scales. Though the first report desig- 

 nates the pest as a menace to coconut 

 cultivation in the Caroline Islands, Dr. 

 Lindinger writes me that— in his opinion 

 —the part played by the insect has 

 been exaggerated, and that the injury 

 to the young palms is more truly at- 

 tributable to excessive drought. 



A corner of the rice field, on the 

 Experiment Station, has been badly at- 

 tacked by caterpillars of a Pyralid 

 moth (Marasmia bilinealis). I do not 

 know of any previous record of this 

 insect as a rice pest. The attack is 

 confined to three or four plots at one 

 end of the field. These particular plots 



