154 



THE AGRICULTURAL NEWS. 



llw 



1904. 



INSECT NOTES. 



The Cotton Leaf-blister Mite. 



In a reiioit to the Iiiiperial Commissioner of Agriculture- 

 Mr. A. .1. .Ionian, the Curator of the Botanic .Station at 

 Moutserrat, gives some of the results of the experiments that 

 have been carried on for the purpose of controlling the leaf- 

 blister mite (Eriophyes </of.f:i//>ii) in that island. These 

 experiments were planned b}' the Entomologist on the staff 

 of the Inijierial Deiwrtnient of Agriculture at the time of his 

 visit to Montserrat in January last. Mr. C. Watson, the 

 Attorney for Dagenham estate, pro\ided land, labour, and 

 much of the material required, while ujjou Mr. Jordan 

 devolved the general supervision of the planting operations 

 and tlie application of the insecticides. 



For the experiment was used ^ acre of land near 

 Dagenham works, which had been cleared of a crop of cotton 

 just previous to the beginning of the experiment. This crop 

 had been badly attacked by the leaf-blister mite. The land 

 was divided into eight plots, and half of each was treated 

 with crude sulphur from the local Soufriere sown l.roadcast 

 at the rate of 100 It), jier acre. Xo effect was obser\ed from 

 this ap])lication. The plots which were not treated were the 

 first to show infestation and they grew .steadily worse. No 

 better results were obtained from the plot treated with the 

 crude Barbados oil and whale oil soap mixture. 



On the other hand, all the plots which received flowers 

 of sulphur, either sjirayed or dusted on the plants, gave the 

 best results. Up to the time of reporting, six applications had 

 been made on each plot, and the results appear to indicate 

 that suli)hur is the remedy to be emi)loyed for this pest. 



A series of box experiments with sterilized and unsteril- 

 ized soil, and with sterilized and unsterilized seeds was also 

 carried out. No effect was observable from the soil 

 sterilization, but it is recorded that none of the plants from 

 the sterilized .seeds developed the disease until it was 

 introduced intentionall}-. The soil used in these experiments 

 was taken from the com[iost hea|i at Grove Station. Had soil 

 from a field which had borne a badly infested crop of cotton 

 been used, it is probable that a difference would have been 

 noticed between the sterilized and the unsterilized .soils. 



Attempts to inoculate healthy cotton plants by bringing 

 them in contact with diseased Acacia leaves failed. This 

 confirms the ojiinion of Dr. A. Nalejia, of Vienna, Austria, to 

 whom specimens of affected cotton leaves and the leaf galls of 

 the Acacia were submitted. Dr. Nalepia was able to say that 

 the mites were different species. 



A brief account was given in the A (jri cultural Neva 

 (Vol. Ill, \>. 42) of experiments on a .small scale which 

 indicated that sulphur was likely to jirove a remedy for the 

 leaf-blister mite, and the results of this field experiment all 

 point in the same direction. The application of these 

 principles to a field crop will be neces.sary to show whether 

 they are practicable, and it is to be hoped tliat further 

 experiments may be carried on extending over the entire 

 growing season, in which the cost of the application of 

 remedies can be reckoned against the yield, so that data may 

 be obtainable for definite recommendations in the future. 



Sugar-cane Leaf Hopper in Hawaii. 



During the past two years considerable danjage has 

 been done to growing canes in Hawaii by a leaf hojiper 

 known as Perh'nsieita saccharicida. So serious has it 

 become that a bulletin has been publi.shed by the Hawaiian 

 Board of Commissioners of Agriculture and Forestry gi\ing 

 a comi)lete account of the pest, and references have been 

 made to it in new.spai>ers in the United States and in 

 Barl)ados. In view of the general interest taken in this pest 

 the following statements may not l)e out of i)lace at this 

 time : — 



The leaf hopper of the cane in Hawaii is very clo.sely 

 related to the cane fly {Ddjih'tx I'dcchaiivora) which is .so 

 common iji the West Indies. In Hawaii it is an imported 

 species, its original home being in Queensland, where it has 

 long been known; but as it has never been destructive there, 

 it probably has some powerful natural enemy which keejis its 

 nund)ers down. In Hawaii, however, it has no such check, 

 and it is attacking canes there with all the force common to 

 imported piests. Attempts are now being made by the 

 authorities to introduce lady-birds which will ])rey upon it. 

 The common lady-l)ird in Hawaii feeds very readily upon 

 the leaf hopper, but it is, in turn, kej)! in check by an enemy 

 which lays its egg in the body of the adult lady-bird beetle. 



There is probably no danger of this pest being introduced 

 into the West Indies, as no plant canes are being brought 

 from Australia, Java or Hawaii, where the leaf hopjier is 

 known ; and further, since planters are fully aware of the 

 serious nature of this pest, they are not likely to take the 

 chance of introducing it by importing canes from those 

 countries. 



A Beetle-borer of the Sugar-cane in Java. 



In the communication No. 70 of the Experiment 

 Station for Sugar Culture in West Java, is to be found 

 a descrijition of a beetle boring in the stem of the cane, with 

 its life-history and an account of its occurrence in that 

 island. 



This beetle {Holaniara picesccns, Fairm.) was first 

 recorded in West Java in 1897 by Dr. Went. Now its 

 distribution is (piite general. 



The eggs are small and are laid singly in the ground. 



The larva when first hatched makes its way into the 

 cane throngh the buds or eyes, frequently feeding first on the 

 young tender roots at the node or following around the line 

 of tender growing tissue just above the node. 



The larval st.age occupies two or three months. This is 

 passed inside the cane in the burrow eaten out by the larva 

 as it works down into the stem. 



The jiupal stage of six days is passed in the ground, and 

 although it is not known how .soon the female begins to lay 

 eggs after emerging from the puiwl stage and how long the 

 egg laying is continued, it is supi>osed that there are only 

 two generations per annum. The larva is about 10 mm. (f 

 inch), and the beetle -5 mm. (i inch). 



Plant Diseases in Hawaii. A jircss bulletin 

 (No. 9) recently pulilished by the Hawaii Agricultural 

 Experiment Station gives an account of two fungoid diseases- 

 of crops in that island. The first disease is the well-known 

 ' pine-ajiple ' disease of sugar-cane, which was reported from 

 one of the windward plantations in 1903. The treatment is 

 that recommended by the Imjierial De[iartment of Agri- 

 culture. The second disease is the • brown-eyed ' disease of 

 coffee, so-called from the brown spots jiroduced on the leaves ; 

 the fungus also occurs on the half-formed berries. 



