266 



THE AGKICULTUKAL NEWS. 



Ai(;usT 12, 1916. 



INSECT NOTES. 



ATTEMPTS AT THE CONTROL OF 



PLANT BUGS. 



The many efforts that have been and are being made in 

 the West Indies to evolve a satisfactory means of control of 

 the cotton stainer, lend a special interest to an account given 

 of work on the closely comparable problem afforded by the 

 tarnished plant bug, Lyjus f^riftenms, in North America. 



The following particulars are abstracted from the section 

 dealing with means of control to be found in bulletin No. 346 

 of the Cornell University Agricultural Experiment Station, 

 entitled 'The Tarnished Plant Bug', by C. E. Crossby and 

 M. I). Leonard. Although the results of the different 

 attempts at the control of this plant bug have been largely 

 negative, they are nevertheless of value as a guide, while 

 there is some possibility that although unsuccessful in regard 

 to the tarnished plant bug, some of the attempts might 

 prove helpful in regard to cotton stainer control. 



It is admitted that the control of the tarnished plant 

 bug is still an unsolved problem. Most of the remedies 

 suggested are either inadequate to meet the demands of 

 pratical growers, unsuited to the conditions under which the 

 crop is grown, or impracticable in other ways As regards 

 the experiments made with contact insecticides, it is stated 

 first that very indifferent results were obtained with kerosene, 

 even under laboratory conditions In the field, the greater 

 part of the injury is done to the plant by the adidt bugs, 

 which are particularly hard to hit and difficult to kill even 

 when struck with the spray. 



i'yrethrum is unsatisfactory for the same reason as 

 kerosene emulsion, and furthermore, it is too expensive to be 

 used on a large scale. 



8oap solutions have not been used successfully. Simil- 

 arly, tobacco decoctions have given negative results as a rule. 

 Deterrents like unslaked lime, sulphur, and ashes have proved 

 of little benefit. 



Many writers, realizing the inefficiency of both contact 

 insecticides and deterrents, have recommended catching the 

 insects in various ways. Jarring has been tried and with 

 success, but only on a small scale. By this method the insects 

 are shaken into pans containing soap or kerosene. In a large 

 field, a fresh sui)[)ly of bugs will soon take the place of tliose 

 captured. 



The insect net and the u.se of sticky shields have proved 

 unsuccessful. 



The Bulletin under review then goes on to consider 

 certain experiments made in New York. This work showed 

 first of all, that the use of insecticides like soap, nicotine 

 and kerosene emulsion for killing the tarnished plant bug 



is entirely out of the question. It is added that it 

 would doubtless be feasible to kill the nymphs in this way, 

 but they do practically none of the damage 



Thinking that a substance with an obnoxious smell might 

 have a deterrent effect, plants were sprayed with a "20- 

 per cent, solution of tincture of asafi.etida diluted 1 oz. in 

 50 oz. of water. On the next day there was no appreciable 

 odour left on the plants, and thei-e were apparently as many 

 bugs present as before. 



Dusting experiments were next tried, and many diffi- 

 culties weie met- with. It was found ultimately, that the 

 cheapest and simplest method was the best, namely, the u.se of 

 tinned quart milk cans, with the bottom perforated with 

 a large number of nail holes to form a kind of pepper pot. 

 Plants were dusted by means of this with flowers o( sulphur 

 and hydrated lime in equal parts: flowers of sulphur and land 

 plaster in equal parts; and land plaster alone. The dusting 

 was discontinued owing to the fact that after a short time 

 praeti;-all_v all the terminals showid some inji.iry on both 

 the dusted and undusted rows. 



In experiments with sticky shields, smeared with 'tree 

 tanglefoot', it was found that the device was not sufliciently 

 efticient to make its use worth while. In an attempt to 

 increase the efficiency of the screen, small branches were 

 tacked on the ends so as to stir up the bugs and cause them 

 to take flight. The result was not successftil, and the 

 device was ultimately discarded. 



Thinking that some sort of suction machine corres- 

 ponding in principle to the well known house vacuum 

 cleaner might be used for Batching plant bugs, a blower was 

 used having a 30-inch fan attached to a 4 h. p. gasoline 

 engine. With this machine, it was not found possible to get 

 enough suction over an opening 8 inches in diameter to 

 draw in bugs resting on the hand and held at the mouth 

 of the pipe. Even if it were possible to construct 

 a suction machine that would draw in adult bugs from the 

 trees, such a machine would necessarily be so heavy that it 

 would lie very ilifficult to mount it so that it could be drawn 

 through the nursery rows. The proximity of the rows to one 

 another would also give rise to difficulties. In the face of 

 these facts it was concluded that this method of catching the 

 bugs is impracticable. 



An experiment with molasses as a trap, showed that this 

 substance otters no attractions to the tarni.shed plant bug. 



The Bulletin under consideration concludes with 

 suggestions for future experimental work in the control of 

 the tarnished plant bug. As this insect flies low it was 

 thought that wire fencing of a small mesh might be used to 

 protect nurseries from infestation. It appears that the bugs 

 will not fly over the fence but they will crawl up it, and 

 once they reach the top, fly down on the other side. It is 

 suggested that a band of sticky substance like tanglefoot 

 might be run around the top of the fence, and such a device is 

 thought to be worthy of trial, and the writers of the Bulletin 

 under notice express their intention of proceeding further in 

 this direction. 



The last suggestion is that bagging might be useful in 

 the case of peach seedling.s, to protect the leaders from injury. 

 It is pointed out that the damage to the tips of the laterals 

 does not atiect the commercial value of the tree. This 

 method therefore is not impracticable, considering that nnly 

 a limited amount of bagging would have to be done. 



