298 



THE AGRICULTURAL NEWS. 



September 13, 1913. 



INSECT NOTES. 



THE USE OF FLOUR PASTE IN 



SPRAYING. 



Results of interesting experiments in the use of flour 

 -paste in connexion with spraying are described by W. ]> 

 Parker in Circular No. ICC recently issued by tbe Bureau of 

 Entomology of the I'nited States Department of Agriculture. 

 In the belief that the information will be likely to be 

 of interest to many of the readers of the AgrnuHural Xeivs 

 this circular is abstracted in the present article. 



FI.OUJ! AS A 'spreader'. 



rT" In the course of trials to find a suitable 'spreader' for 

 the lime-sulphur solutions used as a spray against the red 

 spider {IVtranyrlnis /jimaciilanis) on hops in California, it 

 was discovered that tlour paste not only answered that pur- 

 pose but also seemed to serve, to a certain extent, as an 

 active insecticide. 



As a spreader it was found that when flour paste has 

 "been added to the lime-sulphur solution, it has the ett'ect of 

 causing the spray to adhere to the leaves as a thin film; 

 whilst without the addition of the flour paste, the lime- 

 sulphur sprayed on the plants in the same way, collected in 

 drops or globules. 



For this purpose the flour paste is used at the rate of 

 4 gallons to 100 gallons of the lime sulphur solution, each 

 gallon of paste containing 1 fc. of flour. 



The beneficial efi"ect of the spreading was very consider- 

 able, for whereas the lime sulphur spray used without the 

 'spreader' gave a result of only 37 '5 per cent of the mites 

 (red spider) killed in a certain instance, it was found that 

 with the addition of the flour paste the same strength of 

 lime-sulphur gave results as high as 99 per cent, killed. 



VALUE AS AN IXSECTICIDE. 



A series of trials was made with nicotine-sulphate 

 against the hop aphis (Fhorodon hniiuili) in which Hour 

 paste at the rate of i gallons to 100 gallons of the nicotine- 

 sulphate solution at strengths of 1 in 2,000 and 1 in 3,000. 

 In these tri.ils from 99-100 per cent, of the aphides were 

 destroyed. 



During the trials it was observed that many ' of the 

 smaller aphides were pasted on to the leaves. Accordingly, 

 tlour paste used without any other insecticide was tried, and 

 it was found that when used at the rate of S gallons ( = 8 It), 

 flour) in 100 gallons of water or even stronger (say 10-100 or 

 even 12-100) most of the young and tender aphides (97 per 

 cent.) and of the red spiders were killed, and at the same 

 time, no damage was done to the hop plants even when in 

 lull bloom. 



The older and stronger aphides, and the eggs of the red 



spider, were not killed by the flour paste. In this latter case, 



it was found necessary to make a second application, seven to 



ten days later, in order to reach the mitea that emerge from 



-the eggs. 



COST. 



In a series of five experiments against red spiders on 

 "hops with flour paste at the rate of IS-IOO, it was found 

 that from 998 to 100 per cent, were killed. The solution 

 «08ts only 17-6c. per 100 gallons. 



Flour paste has been used successfully against red 

 spiders upon the following ])lant8: beans, chrysanthemums, 

 "lops, cucumber (in greenhouse and field), pumpkin, pear, 



prune, roses (in field), violets (in greenhouse and field). In 

 the case of chrysanthemums, the leaves may become spotted 

 if spraying is done too near the time of blossoming. Flour 

 paste was not found satisfactory when used upon greenhouse 

 roses, greenhouse carnations or field sweet peas. 



PREPARATION OF PASTE. 



'To piepare the Hour paste, mix a cheap grade of wheat 

 rtour with cold water, making a thin batter, without lumps; 

 or wash th? Hour through a wir-i screen with a stream of 

 cold water. Dilute until there is 1 lb. of Hour in each 

 gallon of mixture. Cook until a paste is formed, stirring 

 constantly to prevent caking or burning. Add sufficient 

 water to make up for evaporation. 



'Flour paste may also be prepared by stirring boiling 

 water into a moderately thin batter until there is 1 lb. 

 of Hour in each gallon of mixture, and allowing it to stand 

 until the starch is all broken down. 



'If the paste is not sufficiently cooked, the resulting 

 spray will not be efi'ective, and if overcooked the paste will 

 harden when thoroughly cool, and will not mix with water 

 very readily. Usually, however, the paste is used as it is 

 prepared, and overcooking is not a disadvantage. 



'When mixed in the spray tank. Hour paste has a tend- 

 ency to settle, and in order to do satisfactory work, agitation 

 is necessary. This is but a slight disadvantage, and is 

 necessary with most materials. 



'Flour paste appears to be a very effective spreader for 

 lime sulphur and nicoiine-sulphate sprays. Cheap Hour can 

 be purchased for less than half the cost of whale-oil soap. 

 It is always obtainable, and having no odour, it is less 

 ottonsive to use than the whale oil and fish oil soaps. When 

 used alone at the rate of 8 gallons (8 B). flour) to 100 

 gallons of water it is eflective against several leaf-feeding 

 mites and some very delicate aphides. The possibility of 

 its use as a spreader for lime-sulphur sprays for scale insects 

 and fungi and as a 'sticker'' for arsenicals has not yet been 

 worked out, but from observations during the past four 

 months it is believed that it may have some value along 

 these lines.' 



EMPLOYMENT IN ODNNEXION WITH CITRU.S FRUIT. 



The Monthly Bulletin of the California State Com- 

 mission of Horticulture, for June 1913, contains a brief 

 account of similar trials by J. P. Neiils of the I'nited States 

 Department of Agriculture in the use of the lime-sulphur 

 solution with Hour paste with check trials in which the 

 lime-sulphur was used without the flour paste added, against 

 the citrus red spider Ti-lraui/rhns inytilaxpidis. Check trials 

 were made with the spray without any flour. 



The objection to the lime-sulphur solution was that it 

 spotted the fruit, that is to say, the spray mixture collected 

 in drops on the fruit, and when the water evaporated, the 

 solids remained in conspicuous spots, which, in the case of 

 the fruit, had to be washed off before it was packed. 



The results of these trials showed that the addition of 

 the Hour paste greatly increased the efficiency of the spraying 

 and that there was no spotting of the fruit necessitating 

 washing. 



WEST INDIAN EXPERIENCE. 



As further evidence of the useful nature of flour paste 

 in spraying, it may be added that a correspondent of the 

 Imperial Department of Agriculture in Barbados has tried 

 Hour paste (8-100) against red spider on roses in the gardea 

 and reports good results from one application. 



