202 



THE AGRICULTURAL NEWS. 



June 26, 1909. 



INSECT NOTES. 



Parasitic Fungi. 

 In the last iiuinber of the Aijricidf aval Newti, 

 a short account was given of the valuable assistance 

 rendered to planters by the natural enemies of the 

 scale insects which occur as blights on limes, oranges, 

 and many other economic plants. 



In Florida, more e.\tcn.sive trials have been made perhaps 

 than anywhere else, in the use of fungi for the control of 

 scale insects, and the whole subject has been given careful 

 -study, with the result that several species of fungi arc now 

 recognized as being parasitic on scale insects. 



".Methods have been devfsed for distributing these 

 fungi throughout scale-infested orchards. One of these 

 is known as the spore-spraying method. The parasitized 

 scale insects are collected on leaves, twigs, or bark, and 

 are carefully scraped oft" into clean, fresh water. The 

 Avater mixture should be thoroughly stirred to separate 

 as far as possible the fungus from the coar.ser part of the 

 aicale insects, and then poured through coarse muslin to 

 remove any particles that might clog the si)ray nozzle 



This water mixture would contain the spores and broken 

 jtarticles of the fungus, which under favourable conditions 

 -would grow. It should be immediately applied to scale- 

 infested trees from a new sprayer, or syringe : or even 

 .sprinkled on by means of a brush or wisp of bush. No 

 sprayer should ever be chosen for this purpose which has been 

 -used for applying Bordeaux or similar mixtures, and it 

 ■would be better not to use the sprayers witli which the 

 ■ordinary scale insect spraying mixtures have been applied. 



The spraying should be very light, the greatest care 

 being taken that the leaves and branches are thoroughly 

 <lamped ; but there should be no dripping from the leaves. 



Another method is the leaf-tying method. Leave.s, 



'twigs, or strips of bark covered with scales that are known 



"to be parasitized, or that have been taken from trees where 



-the ])arasitic fungi are known to be abundant, are distributed 



■throughout trees infested with the same kinds of scales, in 



such a way that the .spores of the fungi may easily find scale 



in.sects on which to grow. 'J'he parasitized .scales should be 



placed fairly high in the tree.s, and in contact as far as 



possible with the healthy scales. This may be done by 



tying or pinning the collected material on to a leaf ol' branch 



of the trees. 



These trials arc, of course, best made at the beginning of 

 the rainy .season, .so that the fungi may have the benefit of 

 the moist conditions which are favourable to their growth. 

 If a dry spell should follow iniinediately after the application 

 of the fungi, it would be useful to spray with clean water, in 

 order that they might not be dried up. 



It is also likely that in those orchards where the fungi 

 arc known to be piescnt, but where scale insects are not being 

 held well in check, a few sprayings with clean fresh water 

 (luiing the dry .season would jirove very useful. It is in the 

 dry sea.son that scale insects make their most rapid develop- 

 ment, and at that time the fungi grow .slowly — if at all — .so 



that the provision oPa small amount of moisture might prove- 

 of great benefit. 



This method of control is worthy of careful trial on the 

 j)art of lime growers and others. Trees that are very badly 

 attacked by scale i||sects might perhaps be sprayed with 

 contact I insecticides during the dry sea.son to reduce the- 

 numbers somewhat, and then at the beginning of the rainy 

 season the -systematic distribution of parasitic fungi would 

 probably result in keeping the scales in check through the 

 year. 



All who are interested in the subject of scale insects 

 would do well to become familiar with their parasitic fungi. 



The local agricultural officers will give all information 

 in their power, and will forward specimens to the Head Office^ 

 where they will be examined and reported upon. 



The Loss Occasioned by Insects that Carry- 

 Disease. 

 The United States Depaitinent of Agriculture has- 

 recently issued Bulletin No. 78 of the Bureau of 

 Entomology, entitled £'('o/(o*;(/c Loss fo the Feople of 

 fill' I'nitcil States iliroiiifli Insfrfs that Carri/ Disease. 

 This bulletin is written by Dr. L. (). Howard, Chief of 

 the Bureau of Entomology. 



The introduction to Bulletin No. 78 is given here- 

 with : — 



It has been definitely proven, and is now generally 

 accepted, th.it malaria in its iliti'erent forms is di.sseminated 

 among the individuals of the human species by the mosquitos 

 of the genus Anopheles, and that the malarial organism gains 

 entrance to the human system, so far as is known, only by 

 the bite of mo.squitos of this genus. It has been proven with 

 equal detiniteness, and has also become generally accepted, 

 that yellow fever is disseminated liy the bite of a mosquito- 

 known as Steiioinijid. calopus (possibly by the bites of other 

 mosquitos of the same genus), and, .so far as has been 

 discovered, this disease is disseminated only in this way. 

 Further, it has been scientifically demonstrated that the 

 common house-fly is an active agent in the dissemination of 

 typhoid fever, Asiatic cholera, and other intestinal diseases,, 

 by carrying the causative organisms of these diseases from 

 the excreta of patients to the food supply of healthy indi- 

 viduals ; and that certain species of fleas are the active 

 ac'cnts in the convej-ance of bubonic plague, iforeover, the 

 tropical disease known as filariasis is transmitted by a species 

 of mosquito. Furthermore, it is known that the so-called 

 ' spotted fever ' of the northern llocky Mountain region is 

 carried by a species of tick, audit has been demonstrated 

 that certain blood diseases may be carried by several specie.s^ 

 of biting insects. The purulent o[ithalmia of the Nile ba,sin 

 is carried by the hou.sc-fiy. A sic.ilar disease on the Fiji 

 Islands is conveyed by the same in.sect. I'ink eye in the 

 southern United States is carried by minute flies of the genus 

 ilippclates. The house-fly has been shown to be a minor 

 f'actm' in the spread of tuberculosis. The bed bug has been ■ 

 connected with the dissemination of .several disea.ses. Certain 

 biting Hies carry the sleeping sickness in Africa. A number 

 of dangerous diseases of domestic animals are conveyed by 

 insects. The literature of the whole subject has grown 

 enorniou.sly during the past few years, and the economic loss 

 to the human species tlirough those insects is tremendous. 

 At the same tiu:e, this loss is entirely unnecessary : the 

 diseases in question can be controlled, and the suppression 

 of the conveying insects, so absoiutely vital with certain of 

 these diseases, and so im[ioitant in the others, can be brought 

 about. 



