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A PANNIER HOPPER-DOZER. 

 By C. B. Williams, M.A., F.E.S., 



Department of Agriculture , Trinidad. 

 (Plate VI). 



In the course of my work on the froghopper {Tomaspis saccharina, Dist.) damaging 

 sugar-cane in Trinidad, it was found that the adult insects could be caught in very 

 large numbers at the time of their broods by drawing large nets over the cane plants- 

 in the late evening and early morning. A number of different types of net were 

 designed and experimented with, and the one described below has proved the most 

 satisfactory up to the present. 



Unfortunately, owing to the very hmited period of dayhght during which the 

 adults can be so caught, the use of these nets as a practical control has not so far 

 been a success. The account below is given entirely in the hope that it may contain 

 some new suggestions that might be appHed or adapted to the control of other pests 

 under other conditions. 



It was necessary to get a net of good width that could be moved rapidly over canes 

 of various heights, without damaging them, and mth the least expenditure of 

 labour. These results were obtained by having two nets in the form of panniers 

 on the sides of an animal (in this case a mule), the whole being wide enough to sweep 

 two rows of cane planted five feet apart when the animal walks between the rows. 



Very httle description is necessary if the figm'e and plate are examined carefully. y., 

 Most of the details are unimportant and could be varied to suit local conditions. 



Each net is hinged behind and is supported in front by a stout cord or wire that 

 is attached to the front supporting bar. This is loose in its bearings, and by rotating^ 

 it the front of the net can be raised or lowered, which can be done by the boy in the 

 saddle, \\dthout getting down, as the height of the canes changes. The nets in the 

 machine figured could be lowered so that the bottom edge was only a few inches 

 from the ground, when they could be used in long grass, or raised until there was 

 about three feet clearance. It was not found feasible to send mules through canes 

 requiring the nets higher than this. By removing the stop on the rear bar and 

 unhooking the front supporting cord, each pannier can be removed in less than a 

 minute. 



The nets are open in front and may be smeared inside with some sticky substance,, 

 or the opening could be fitted with a shutter arrangement of netting to prevent the 

 escape of the insects. In the present machine they are of wire mosquito netting, 

 but strong cloth or even thin wood might be used. The advantage of the net is 

 that it allows the air to pass through, and does not create a back-draught. 



The framework of the nets and saddle was constructed of wooden bars, one inch 

 by two inches, while the main supporting bars, rear and front, were one inch iron 

 tubing. The saddle should be well padded and securely strapped down with two 

 girths. 



